Fossil Grasses

433 ORDINARY

MEETING.

F RIDAY, A PRIL 2ND, 1886. W . TOPLEY, E sq., F.G.S ., Assoc. Inst. C.E., President , in t he Chair. The donations t o t he Library sinc e the previ ous m eeting wer e announced , and t he t hanks of the Association accor de d to the don ors. The following were elec te d Members of the Asso ciation :-C. J . Alford, }~.G .S .; E. Edwards; W . H oe; Mi ss M. C. Mond y ; Mark Stirrup, F .G.S . ; E . H . Winst one, M.A. It wa s then put t o t he vot e whether July or Augu st wer e the m ore convenient month for the L ong Excursion, and car r ied in fa vour of the latter. The following paper was then r ead : , On Grasses,' by J. Starkie Gardner , F.L.S., F.G.S. Dr. Henry Woodward , F .R.S ., &c., Keeper of the Geological D ep ar tment, British Mu seum , exh ibited and explai ned a ser ies of fossiliferous n odul es from the P enny-Stone Ironst one of the Coal-Measures near Dudl ey, and Mr. Gardner exhibited spec imen s in illustration of his paper.

F OSSIL G RASSES. B y J . STARKI E GARDNER, F.L.S., F.G.S.

It will doubtless appear r ather bold on my par t t o endeavour t o engage your attention to -night in t he det ail s of a group of pl an t s that are r ar ely found fossil , and whose r emai ns are at best of a nature little calc ulated t o arres t the at t ent ion of the geolog is t. It is impro bable that any large number of the Member s of our Association have ever heard of a fossil grass. At first sight it woul d appear difficult, from our stand point , t o h av e select ed a m ore barren and unprofitable subj ect for discussion. Nevertheless, I h ope t o sh ow that the grasses yi eld t o none, even in their ge ologi cal inte r est , when we take into consi derat ion the profound changes in almost every kind of t errest rial life that their appearance on the earth's surface has effect ed . The Glumacem, or gr eat Glumal alliance, to which grasses

434

J. STARKIE GARDNER ON F OSS I L GRA SSE S.

belong, com pr ises five gr eat or ders , in cluding all t hat mass or veg etation known as se dges, rushes, an d r eeds, b esides t he true grasses ; an all iance that combine d furnishes, according to Lindley , at least nine-tenths of the i ndividuals com posin g the present vegetation of the world. W e shall, however, limit ourselves to-ni ght t o a consider at ion of the t r ue Graminece, and t he qu est ion r equiring so lution is, When did t h e Grnminco: or true grasses first m ake t heir a ppearance? The impor t ance of t his qu esti on will be under st ood whe n it is stated t hat t he Gra minece are by far t he m ost imp or tant ord er of t he Glumal all ian ce, and are se cond only, amo ng Monocotyledons, in t he number of t heir sp eci es to the Orchi dacete. They are classified by B entham into t h irteen families, con taining 298 g enem , an d between 3,100 and 3,200 species, t he ir r evi sion for Bentham and Hooker's 'Genera Plantarum' h aving occupied the for mer author for over twelve m onths' hard an d continuous work. Their distribution is univer sal , for they eve r ywhe re r each to the confin es of p erpetual snow, an d occur under t he Equat or. They are equ all y at h ome in sa n d or in t he m ost ar id was tes, and in wat er. The extra-tro pic al spec ies are sm all and greg arious, an d cro wd t oge ther to for m turf, but t he t r opica l grasses are of larg er size, and even assum e t h e ap pear anc e of trees over 100 feet in h eight . The grasses include all the British cer eals, as well as ri ce, maize, an d millet. Our imports of these am ounted even five years ago to the value of ab out £60,000,000, an d in 1883 stood at 40s p er h ead for the entire populati on. It is n o ex aggeration t o say that our bread is bak ed and our bee r brewed from grass; but t his is not all, for we import between 20 an d 30 million p ounds' worth of the pr odu ct s of another grass, the sug ar- can e, and when we add t he v alue of fibr es an d other pr oduct s, t h e t ot al impor t s of grasses, in even our own sma ll countr y, is li ttle short of 100 million s. In E ngl an d two -t hi rds of our area is under cu ltivat ion an d pastur e, and m ore t ha n three-fourths of t h is is occupied by grasses. In Europe, exclu sive of minor States, out of a t otal acreage of 1,863,000,000, the qu antity reported under cereal s and grass is 548,000,000 acres. If we exc ept Russia , one -t hir d of the en t ire area, includin g lak es, river s, and mountains, is devot ed t o t he g ro wth of var ious species of grass. 1Ve h ave but t o vie w our meadows

435

J . ST AR K IE GARDN ER ON F OSSIL GRAS SES .

an d pastures, and our br oad fields of cor n, to r eali se t he para. moun t importance to man of t his or der of pl ant s. M ead ows, it is true, ar e riot entir ely fin ed wi th grass, though the proportion of alien pl an t s is very sma ll. Sinc lair* giv es a t abl e showing the number of distinct r oot ed pl an ts of various specie's found in one sq ua r e foot in nine separate localities. 'I'h e number var ied from 1,798 to 634. The former number ap pear ed in a square foot of well- m an aged wat er-me ad ow, and of t hese 1,702 wer e grasses, and only 96 clover and ot he r plants. Of 910 pl ants in a foot sq uare of old pasture in W oburn P ark, 880 were grasses, 30 clover an d ot her plants, thc numb er of separate species bein g only 12.t When such facts are brought home to us, it be comes difficult indeed to imagine a world without grassy jungles, prairies, and savannas, with no meadows or undulating downs of greenswar d, and deprived of the belts of verdure which extend

* •R ortus Gramineus

Woburnousis ' (1824), p. 244, 8th edition.

t Drs. Oemler and F uchs (' Die Lan dw irth Versuchs-Stat., Bd , xv ii, 211) g ive the follow ing table showing the number of plants growing in one squa re foot of meadow land in Sc hleswi g : No. of P la n ts . Fes tu ea pra tensis 100 H olcus la nai li S 66 P oa pra tensis 64 Phleum pratense ... 59 Avena elatior 41 D acf!Jlis g lome ra /a 32 L olium p erenne (fine ) 24 L oli urn p erenlle . .. 22 A lopecurus protens is 14 * Rllmex A cetosa '" 4 -R a nUJlClll u8 rep ens

P oa allnua

3

2

.. . 431 Per square foot (All of which are grasse s exce pt 7 marked !t). These exa mp le s, fro m La wes , Gilbe r t, and Mast ers's report on t he Mi xed H erbage of Perman ent Mead ows, ' P hil. 'I'rans.,' 1882, p. 1207, s how the enormous pre po nd orance of th e grasses in indi viduals. On tho ot he r hand, of 81l specie s f ound in the experimental plots at Messr s. Law es an d Gil be r t' s, only 20 were Gramin eai. Some of these were only infinit esi, m a lly r epresented, and th e gra sses. as elsewher e, constitute by f ar th e larg er prop ortion of the plants foun d on th e plots. Their greater or less prevalence is very much an affa ir of seas on, enconr a ging or discouragi ng , a s the case may be, the growth of the ir corupe t.itors . The strng g le betwee n g rasses a nd the Lrg1l1l1 ill o.' aJ is esp ecia lly severe, and Dnreau de Lamall e recor ds t hat he ob serv ed in some iso lated plateaux, nev er ma n ured or irrig ated, grasses and L equ mi nosai lose a nd r ega in a r elative ascendency one over th e other five or six t imes in th e course of 30 years.

436

J. STARKIE GARDNER ON FOSSlI, GRASSES.

between the limits of trees and of snow on mountain chains. Yet for countless ages the world rolled on, and animals lived and died, without so much as one blade of grass being present on its surface. Before proceeding further it will be as well, perhaps, to define what a grass really is. The literature of the subject is very voluminous, for special works have appeared upon the grasses of civilised as well as uncivilised countries. A brief account must suffice here. Their flowers, it is well known, are green, and in little clusters, attached to a common axis and arranged either in a spike, a raceme, or a panicle. Wheat is a familiar example of the first, and oats or rice of the last-named. The spikelets composing the spike each have three or more concave scales or bracts, called glumes, the two lowest of which are nearly opposite to each other, and empty. There may be one or more florets in the spikelet, and these are formed variously; but the most usual arrangement is for the floret to be composed of an outer valve formed of the flowering glume, rough and keeled exteriorly, whose mid-rib is frequently prolonged into a spike called an awn, and an inner valve of a thinner,' light, and transparent character, fringed with hairs. These together form a chamber in which three or more bulky stamens, and the ovary, surmounted by two feathery or hairy stigmas, are contained. This chamber is so completely closed in some grasses which have bisexual flowers that no foreign body can gain access, a matter of some importance, as we shall see, in the fertilisation of the plant. There are often in addition two or three minnte scales at the base of the ovary, thought by many to represent the petals, while the pales form the calyx.* Sachs gives diagrams showing how the flowers might have been derived from the ordinary monocotyledonous type through the successive abortion of parts, and Grant Allen states in one of his popular works that they are actually degenerate descendants of showy petaliferous and entomophilous flowers. The latter view, at least, is not quite supported by the few facts known regarding

* Though the flowering glume, or outer pale, and the two-nerved inner pale were thonght by Robert Brown and others to represent the three sepals of a calyx, the flowering glnme is, in fact, inserted lower down, encircling the floral axis as a bract, whilst the inner pale consists apparently of two united braoteoles.c-En,

J. STARKIE GARDNER ON FOSSIL GRASSES.

437

their ancestry. The flowers of bamboo and other more tropical and arborescent grasses are, however, far more perfect, possessing an inner perianth and six stamens. Pariana has large polyandrous flowers which look as if they might belong to a palm rather than to a grass. The stem above ground, called the culm, is cylindrical and jointed, and in the great majority of cases hollow with solid articulations. It is developed with great rapidity, the tissue of the articulations retaining for a long time its power of growth. Thus when the stem is bent and prostrated to the ground by wind, the re-elevation into an erect position is brought about by the surface of the node which faces the ground growing rapidly and strongly until a kneeshaped bend is formed by which the upper part of the culm is raised up. Iu some there is but one stem, and in others the culms are numerous and tufted. Many of the species have creeping underground stems, which descend vertically, or at various angles, or lie but slightly beneath the surface of the soil. Some have dilated and tuberous rhizomes; and the roots of others are tufted as in the hummocky grasses, and of others creeping. Some root abundantly and others but sparingly. The leaves are narrow, parallel-veined, and alternate, with a split sheath, and a membranous expansion at the junction ofthe petiole and blade, called a ligule. In the tropical forms the leaves are broader, and approach more nearly to tbose of other plants. The geologist, however, has to examine their characters far more minutely if he hopes to recognise them in a fossil state. Unlike most other Monocotyledons with leaves resembling them, the blades of grasses are always constricted at the base into more or less of a petiole or foot-stalk before sheathing round the stem, so that the leaf is imperfectly separated into sheath, foot-stalk, and lamina or blade. It presents in this respect a higher degree of development, or greatcr approach to Dicotyledons, than plants which have preserved a more primitive type of leaf with simple amplexicaul or sheathing base. In the next place, the leaf frequently possesses some kind of midrib, often very definite indeed. The parallel veins usually all proceed from the base, but sometimes many of them start from the mid-rib, so that the leaf is partially feather-veined. Its parallel veins may be of equal strength, or certain regularlyspaced ones may be stronger than the rest, and the intervening

438

J. STARKIE GARDNER ON FOSSIL GRASSES.

ones all similar. More rarely every alternate one of the intervening veins is weaker, and the transverse connecting veinlets may in these cases cross the most feeble. Often there are no transverse veins, and the parallel veins are then sometimes incredibly fine and closely set; but, when present, the connecting veins always form a more or less rectangular network. They rarely cross even the most subordinate of the longitudinal veins, and two never meet at the same point; so that the transverse veining is irregular, and in contrast to the other. Sometimes the principal veins are hairy, and sometimes they are closer together at the margins. The transverse veins, again, may be widely spaced or close together, and may be altogether regardless of symmetry, or in a certain order. Altogether, unlikely as it might appear to attempt to distinguish specifically one blade of grass from another, it is by no means improbable that the general plan of the leaf may be susceptible of such endless modification in detail as to render it possible to distinguish the species. The improbability has in any case wholly vanished with regard to the seeds, for Mr. Carruthers's vast experience as Botanist to the Agricultural Society has enabled him to distinguish without trouble the seed of any of the innumerable species of grass now grown in this country. The leaves of grasses always have a hard and stringy, drawn-out look, contrasting with those of plants which store up food in bulbs and tubers, and therefore develop fleshy leaves, with veins within the mesophyll. Another peculiarity shared by few Monocotyledons is the ligule, a small expansion proceeding at right angles from the inner face of the base of the blade. An extraordinary and fundamental change in the conditions of vegetation seems to have been brought about with the advent of grasses. It is quite possible that, until they appeared, no herbaceous vegetation at all existed, except such as grew in the shade of trees or in swampy places. The surface of the earth, as we see it now, even in new and wholly uncultivated regions, is diversified into wood and prairie; yet there seems nothing to prevent much of the latter from immediately reverting to forest, except that the dense covering and matting of grass, and the destructive mammalia attracted by it, renders it difficult for the seeds of forest trees to struggle to maturity. One of the great causes of the ascendancy of grasses seems to

J. STARKI E GAR DN E R ON F OSSIL GRA SSE S .

439

lie in t he fa ct t hat t hey alone among vege t at ion, except as sociated plants that h ave t aken on t he same habit, can be browsed and trampled upon with r elative impunity." More over, the innumerable sp ecies of grass have diverged and varied in every direction, so as to overcome ever y possible comp etition and antagonism, and every vicissitude of station and climate. A change, such as drought or very low t emperature, may kill off surface-roo t ing species; but others , wi th deeply-, p enetrating ro ot s, are at hand t o quickly spre ad in their place.t The humbler grasses are thus enabled t o hold their own against shrubs ·a nd trees, bu t it is very doubtful whether the as sociated herbage, deprived of t he shelter and aid of grasses, would be abl e t o maintain it s exi stence. Most of the associated meadowflowers seem to be designed, in fact, expr essly to compet e with grasses . Thus the P lantain, the Dandelion, the Hawkweed, Daisy, and many others have the form of flat ro set tes, closely pressed to the soil, quite preventing t he gr owt h of other plants, and secur ing space and light for their flower- sp ike s. In some, • The in fluences which hav e led to count r ies , even under th e tropics, being divided in to t ra c ts of g rass, called prairi e or sava nna, and tracts of fores t, have heen hotl y di scussed. Th ere can be no doubt t hat pover ty of soil and ab sence of mois ture may hav e orig inally fav oured grasses in t he struggle for as cenda ucy ; whil e the recurrence of prairie-fires and t he ac tion of browsing a ni mals h ave been impor tant factor s in maintaining tracts, already under g rass, free from th e inv asion of trees. t There can he no doubt th at their ha bit and direction, whether erect or de cumbent and creeping, their number and t exture powerfully influence the terms on which they compete wi t h other plants. Some grasses seem to disregard completely t he nature of the soil and all external conditions, and if left to t hemselves largely monopolise t he gr ound, wh ether sand, loam, or li me, drain ed or und rained . Even the sha de of trees does not suffice t o banish th em, and th eir powerful underground runners assure them a supremacy e veryw he re. 'I'h ey form a ne twork of ro ots mor e or less dense, and to a gr eater 01' less depth, accord ing to the particular species, and ex tend or ramify at differ ent angles and in different directions and to varying dep ths, according to the mech an ical, chemical, a nd hygroscopic qu alities of the soil. "Just beneath the surface are th e root-stocks , firm and mor e or less woody, jostling their neighb ours, pushing t he m aside, or e mitting sle nder, creeping stolons t o tw ine t he ir devi ous co nrs e among other pla nt s. Or the competit ion may be chiefly above ground. Th e dense tufts of some grasses occupy the surface, and prevent the growth of nei gh bour ing species. In other cases the creeping ste ms , the offsets, the runners-a hundred differ ent forms and adaptations, provid ed fo r the benefit of the in d ividual plan t, a s weap ons of offence or defence, or as store-h ous es for nutrimen t-contribute t o the result. So agai n, also, is it with the form, the arra ngement, the de ve lopme nt of leaves, an d also of the flowers and seeds."- La wes, Gilbert, and Masters, "Phil. Trans.," 1882, p. 1226. Som e cereals ha ve been profoundly modifi ed by man ; thus all the varieties of Zea, or Maize, have been pro du ced f r om a single Brazilian form, itself perhaps modifi ed frOID a wild parent.

440

J. STARKIE GARDNER ON FOSSIL GRASSES.

as the Buttercup, the foot-stalks elongate as soon as the plant starts into growth in the spring-time, and make room thereby for the encroachments of grass. " In plants like Conopodium denudatum, the leaf in its initial stage is packed into very small compass, almost like a furled flag. In this state it is thrust up amid other leaves till it gets space to unfold. In other cases, as in the clovers, the two halves of the young leaves are folded like a sheet of note-paper, and remain so till, by the lengthening of the stalks, they grow beyond the obstruction. . . . In fine, there are endless adaptations, such as those cited, wellknown to the botanist, and familiar to the most superficial observer of plants." (Lawes, Gilbert, and Masters, "On the Mixed Herbage of Permanent Meadow," 'Phil. Trans.,' 1882, P: 1219.) It is likely, therefore, that these, and probably nearly all our meadow herbs, were developed subsequently to grasses, and perhaps the origin of entire tribes of plants must be postdated to them. If we take up any list of Eocene plants we shall see that the genera are precisely those which are not fitted to exist socially with grasses. The Bracken is an apparent exception, but it may, like the Gorse, have been but recently adapted to new conditions. Soon after grasses were well-established, however, meadow plants became associated with them. In the uppermost Eocene of Aix we have, among others, the Clover. In Miocenes we find the Strawberry, Meadowsweet, Rose, Liquorice, Lucerne, and Trigonella; and finally, at Oeningen, 21 species of Composites, compared to Thistles, Dandelions, etc. The absence of any such plants in the older Eocenes must, I think, be regarded as something more than a coincidence. The earliest supposed English fossil grasses have been described as Poacites, a genus to which doubtful grass-like leaves are by common consent referred. Two were recorded in Lindley .and Hutton's 'Fossil Flora of Great Britain,' from the Lancashire Coal-Measures, but they have been allowed to drop out of their position since 1865. Few, indeed, would now question the truth of Brongniart's assertion, made in his last and most exhaustive work on the silicified fruits of the Carbonirerons or St. Etienne, that Angiosperms were completely wanting at that period. There are, in fact, as he affirms, no definite traces of them until Jurassic Rocks are reached, when

441

J. STARK IE GARDNER ON FOSSIL GRASSES.

several apparently true Monocotyledons make their appearance. The next oldest supposititious grass is, I believe, from the Lias, Bambusium liasinum of Heer," a name attached to some exc eedingly problematical remains; and then we have Culmites of Ettingshausen from the Wealden, and Bambusium neocomiense of Heel'; but as these, from their imperfect state, might b elong to almost any monocotyledonous genera, we cannot accept them as evidence of the presence of true grasses in these remote times. I must not omit to mention the occurrencet of a very Bamboo-like, and undoubtedly monocotyledonous stem in the Jurassic of Yorkshire. With the Cretaceous, remains attributable, if not to the grasses themselves, to the great Glumal Alliance, become more numerous; but almost all these come, be it remarked, from the Upper Cretaceous Beds with Dicotyledons.I of uncertain age, and not from the series as we know it in Great Britain and W estern France. There are some remains from North America and others from Europe pl aced in the genus Phragmite s, but it is scarcely safe to say more about them than that they are parts of Monocotyledonous pl ants. In the oldest Cretaceous of Greenland, the Kome-sohichtcn, a mere fragment of a leaf is placed by Heer§ in the widely comprehensive genus Poa cites. From the Upper Cretaceous of the same regions a hollow-jointed ste m and leaves are placed in the genus Arundo, as well as similar and more perfect stems from the still newer Cretaceou s of Patoot. The evidence is inconclusive, but it is, perhaps, safe to agree with Schimper II that the great Glumal Alliance entered on the scene towards the close of the Cretaceous period. Setting aside the doubtful fragments previously alluded to, one of the earliest genera of Gluanacece, at all definitely known, is the Rhizocaulon of Saporta,' from the lignites below the gypseous series of Aix. This unites, in the opinion of that author, the characters of three now separate orders, and

* , Flora

Helvetioo,' p. 138, pl . 55.

t Communicated by Prof. Williamson.

See also 'Quart. Jonrn, Geol, Soc.,' Vol. vii, p. 189. :t Such as Aix-Ia Chapelle, Niderscbona, etc. § 'Flora fossilis Arctica.' II 'Paleontologie Vegetale.' , , f:tudes sur la vegetation tertiaire du Sud-est de la France,' Vol. i, YOL o

IX., No.6.

31

442

J. STARKIE GARDNER ON FOSSIL GRASSES.

tends to show that the Glumal Alliance was at that time in an imperfectly-developed state. Their pronounced characters should render the determination of grasses in the fossil state relatively easy. Judged by these tests, there are none in any of our older Eocenes, nor even in the Bournemouth and Bovey Beds. There are certainly a few seeds and large jointed stems, particularly at Bournemouth and Hordle, which would be claimed as Bamboos by many writers, though it is not even certain that they are Monocotyledons. There are in the same beds parts of large sword-shaped leaves, with reticulated venation, and similar remains occur at Studland and in the Eocenes of the north of Britain; but there is so far no reliable evidence referring them to grasses, and they more probably belong' to the Typhacece or some other Monocotyledons. The same may be said of 'certain jointed rhizomes from Ballypalady. (See Plate V). There are, of course, innumerable obscure fragments of vegetable matter in all these beds that look as if they might belong to the Graminece, but I have never yet seen either a stem, leaf, flower or seed, in them that can be definitely identified as that of a grass. In the equivalent beds abroad we meet with nothing beyond sword-shaped leaves and jointed rhisomes until the Middle Eocenes are passed. The oldest grass leaf, possibly a Bamboo, known to me is the Poaciies Roginei, Watelet,* from one of the Upper Beds of the Paris Basin Eocene (Sables superiours aux lignites), though its supposed flower-spikes are only coniferous branches. But grasses are quite abundant in the Gypseous series of Aix, of Upper Eocene age, and comprise, according to Saporta, perfectly recognisable remains of Arundo and spikes analogous to those of Brachypodiwrn or Barley-Grass. There are also many appearances suggestive of grass remains in the Bembridge Marls of Gurnet Bay. (See Plate IV). With regard to their absence in the Lower, and even Middle Eocenes, we may suppose either that their remains are there, but have been overlooked; or that their habits rendered it difficult for them to become imbedded in such deposits, or that the climate was unfavourably hot; or, lastly, that grasses had not come into existence, or, at least, were exceedingly rare in our area. With regard to the first supposition I can only say that I have worked without intermission for three months at a time at

* 'Plantes fossiles

du bassin de Paris,' p. 61.

PLATE

IV.

GRASS-LIKE REMAINS FROM THE BEll BRIDGE MARLS, GURNET BAY.

r"ig. 1.

Hollow-jointed culm and flower spikes, probably of a grass. la, a spike magnified. Fig. 2. Fragments of a spike, suggesting Briza. 2a, the same mag"nified. Figs. 3 and 4. Flower spikes, probably of grasses. 3a and 4a, the same magnified. Fig. 5. Small fragments of leaves and flowers, and seeds, probably of grasses. 5a and 5b, the same magnified. Fig. 6. Parts of l\ similar flower spike. 6a, the same magnified. Fig. 7. A tract. 8, a fluwer spike; 9, the remains of a spike with tract. Sa, 9a, the same magnified, prubably belonging to the Restiaoees, and resembling Elegia. Fig. 10. Fragment of a hollow-jointed culm. Fig. 11. A ribbon-Iike stem, with scars of rootlets. Fig. 12. A root of reed or grass. 12a, the scars magnified. Fig. 13. A flower, indeterminable. Fig. 14. Part of a Monocotyledonous leaf. Fig. 15. Fragments, probably of Typha. Fig. 16. Stem and leaves, probably of Eriucaulon. Fig". 17. Fragment, probably of Typha. Fig. IS. Frag'ment, apparently of a moss. 18a, the same magnified. The originals lent by E. A'COUl't Smith, Esq. PI.ATE

V.

REED-LIKE REMAINS ntOM THE EOCENE.

Fig. 1. need or Typha-like leaf from Bournemouth. la, part magnified. Fig. 2. A compressed stem from Ballypalady. Fig. 3. Part of-a narrow reed-like leaf from Ballypalady. Figs. 4 and 5. Base and blade of sword-like leaf from Ballypalady. Fig. 0. Part of large Monocotyledonous leaf from Ardtem Head. Fig. 7. lleed or perhaps Sparganium from Bournemouth. 7a, magnified. The originals in the British Museum.

Proe. Geol.Assoc.Vol. IX. Pl.1V

"'2"

J

:>....

.. a.

s

~

8 Go.

S"

1

5"

8

10

12"-

11

18

18 0.

18 West,Newman, &.G9i.mp

Grass -like remains fr-om the Oligocene, Gurnet Bay.

Pr-oc.G eol.Ass ocVoL IX.Pl.V

2

6

Ree d-like r-e'rri arn s from th e E o cene.

W£st$ewm.a.n.-.t C~ intp .

J. STARKTE GARDNER ON FOSSIL GRASSES.

443

Bournemouth at a single plant-bed, during which thousands upon thousands of fragments of plants have been exposed to view without any trace of a genuine grass being discovered. The beds are full of the remains of other herbaceous plants, such as ferns, and it is to the last degree improbable that if grasses had existed in the neighbourhood they could have escaped becoming imbedded and discovered. N or has anything resembling a grass stem been discovered among the thousands of specimens collected at Sheppey, though Prof. Moseley relates that stems of a large cane grass were conspicuous among the drifted fruits and vegetable matter off New Guinea.* The same remark applies in a less degree to the leaf-beds at Studland, Alum Bay, and Reading. With regard to the second supposition, it is perfectly true that the majority of grasses are herbaceous plants, shedding no leaves and decaying where they grow. Their tiny bracts and seeds are blown by the winds and would form inconspicuous objects when imbedded in the clays, marls, and limestones in which plant-remains are mostly found, while their leaves and stems decay down where they have lived. Yet notwithstanding this, as soon as the Oligoceues and Miacenes are reached, the remains of unmistakable grasses are by no means rare. They, in fact, abound in the Oligocene basins of Aix and Marseilles, in that of the Wetterau in Germany, Bilin in Austria, Sinigaglia in Italy, but above all at Oeningen in Switzer-land.'] It is impossible to suppose that all the older Tertiary Beds were deposited under conditions unfavourable to the preservation of grasses, if any such existed, because every description of plant is associated together in most of them, and it would indeed be a. singular coincidence if all the beds above a certain horizon were favourable to their inclusion, and all below it were unfavourable. Many species of grasses habitually grow close to the water, and still more in meadows liable to inundation, and we may safely assume that nothing short of a combination of circumstances of an extraordinary nature would suffice to exclude all traces of them from any fluviatile or lacustrine

*

'Notes of a Naturalist on board the" Challenger," , p. 432. t This evidence negatives the idea put forward by Lindley and Hutton that grasses would not be preserved in fossil floras. They decay. however, more rapidly than Ferns and Gymnosperms.

{'14

J. STARKIE GARDNER ON FOSSIL GRASSES.

deposit now forming, in which great assemblages of plantremains were becoming preserved. With regard to tbe high temperature of the Eocenes excluding grasses, I wrote to Dr. W. T. Blanford, whose long residence in India qualifies him to speak authoritatively on the subject, He has obliged me with the following reply to my inquiry:" So far as my experience goes, grasses of all kinds, from the smallest herbaceous forms to the largest Bamboos, abound in those tropical countries that I have visited, and are common in low-lying grounds, on the banks of rivers, and around marshes. The Indian and Burmese river-plains, those of the Ganges. Brahmaputra and Irawadi, for instance, where quite uncultivated, are mostly covered with gigantic grasses from 5 or 6 to 20 feet high, but this may partly be due to the circumstance that in such tracts great £res take place almost year-ly, and snch fires destroy trees but do not injure the roots of the grasses, Quantities of grass-stems are usually carried down by river floods in the tropical rivers of India, and I think I have heard that the same thing happens elsewhere." Dr. Spruce (' Journ. of the Roy. Horticu1. Soc.,' New Series, Vol. iii, p. 4) shows that in the deposits of South American rivers, at all events, grasses could hardly be absent at the present day :-" In gently flowing rivers of Tropical America grow many fine aquatic grasses, species of Lueiola; Oryza, Leersia, etc. The following note is from my journal, under date December, 1849, when threading in my canoe among the islands of the Trombetas :-' This channel was Ened on both sides by a beautiful grass (a species of L1lziola) growing in deep water, and standing out of it two or three feet. The large male flowers, of the most delicate pink, streaked with deep purple, and -with six long yellow stamens hanging out of them, were disposed in a lax terminal panicle; while the slender green female flowers grew on the bristle-Eke branches of much smaller panicles springing from the inflated sheaths of the leaves that clothed the stem. . . . Gyner'ium sagittatum, the great Arrow-cane (a Pampas grass), clothes the beaches of the Amazon and springy hillsides in the lower Andes with its graceful stems (20 or more feet high), that bear upwards a fan of distichous sword-like leaves, and are topped by an immense panicle of silver-andpurple flowers, which are truly dioicous. ,"Vhen the summer winds sweep up the Amazon, or the squalls of the rain)" season

J.

STARKIE GARDNER ON FOSSIL GRASSES.

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burst upon it, the Arrow-canes bend like osiers, and intermingle their feathery heads, male and female." We shall thus probably not be far out in assuming that grasses did not appear in any numbers in our area until the time of the Upper Eocene. Whether they were abundant anywhere else at that epoch it is impossible to say, but no floras of similar age, with probably one exception, are any more provided with them than our own. That exception is Spitzbergen, where an enormous series of plant-beds, no less than 3,000 feet thick, are preserved. Whether the fossil remains of grasses which have been brought home are scattered throughout, or whether they appear at any definite horizon, and how, are secrets locked, with who knows what others, in the rocks of that inhospitable land. Dr. N athorst informs me that they occur from the base of the Tertiaries, but this is at present an exceedingly vague term as applied to Arctic deposits. Most of the fossil grasses are imperfectly known, and have been placed, to the number of over 40 species, in the provisional genus Poacites. Heel' believed it possible to come to more definite determinations in some instances, and we find species assigned to several existing genera. Panicum, the millet-grass. is found at Oeningen,* and has been also recorded hom other deposits. Its fruit is stated by Saporta t to be enormously abundant in the fissile limestone of Manosque in the South of France. Most of the species are compared to Brazilian forlll-s, many of which grow to a height of six or seven feet, but that from Oeningen is said to resemble closely the cultivated "Wanse" of India. Another species from Oeningen t is said to agree exactly with 01'yza satira, the common rice, except in the smaller size of the grain. This is a plant supposed to be indigenous to Asia, though travellers have reported it as growing apparently wild Oll the banks of South American rivers. It is only cultivated successfully where the ground is liable to inundation, and feeds more human beings than any other plant. The Festucea: are represented by two genera. A jointed stem, and also leaves like those of Aruiulo have been described from the Upper Cretaceous of Atane in Greenland, and others from

* Reer, 'Flora Tert. llelv.,' Vol. i, pp.

66-7.

top. cit., Vol. i, p. 219.

t

Beer, , Flora Tert. Helv.,' Vol. i, P: 63.

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J. STARKIE GARDNE R

ON

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the still n ew er beds of P a toot by H eer," an d from t he Cretaceous of N ebraska by L esquereu x.f Several species of t he sa me ge n us h ave b een r ecorded from t he 'l'erti a ri es of German y , A ustr ia, Ital y , S witze r la n d, an d France, w hils t ot h ers are pl a ced in a pr ovi si onal genus A'rundinil es by Saporta. On e of t he se seem s indisti nguishabl-e fr om t he h an dsom e Anm do Donax , which even in English gar de ns attains a h eight of eight or ten f eet, and is else where fa shioned into fishing-r ods, canes, a n d musi cal inst rumen t s. Species of another ge n us , Ph raqmites, often accompany A ru ndo in Eur ope, an d a fragment is r ecorded by H eel' fr om Alask a .t These n early r esemble our in d igenous P. commumis, the largest of Br iti sh gr asses, which also ranges t o Western Asia, and whose r oot s are seen binding t he river-banks together. A leaf determined by Ettingshausen as Uniola is recorded from Bilin.§ Many of the foregoing were orig in all y referred to Bambusium, but only one fossil sp eci es from the Pliocene of M cximieu x , II where it seems very abundant, n ow remains in that f amily. The species is remarkable among grasses on account of it s gigan t ic size. In both the East an d W est Indi es spe cies freq uen tl y grow to 50 an d 60 fee t , an d even 150 feet in h eight , with a ste m 18 inches in diameter, and t hey h a ve be en known in palm-hous es in this country to make a growth of 40 feet in one season . There are thus no definite fossil r epresentativ es, unless it b e from S pitz bergen, of t h e enorm ous ly valuable g ro ups, t he PIIALARIDE.E, including t he Mai ze ; the AGROSTIDEN., in cl uding the " Be nt-Grasses;" t he AVEKACE.E, or Oa t f am il y ; t he H ORDE..E, including Wheat , Barley, and R ye; an d t h e A NDROPOGONE..E, which in clude t he Sugar Cane. S om e d eg ree of collateral evi de nce as to t he r ela ti vely r ecent origin of grasses is perhaps t o be found in the enor mous number of existing ge nera and sp ecies whi ch t he or de r contains . It m ay be almost ac cep t ed as an axiom that t he larg est ge ne r a have their species t he m ost ill-defin ed and the m ost li able to variation. This appears t o m ean that they are so new ge ologically that the connect ing links have not di ed out . In such genera of the (lramin ece as Eragrostis, Panicusn; Pa sp alam.

*

Fl ora fossilis Arctica.' American Jonrn. Sci. a nd Arts,' Vol. xlvi, p. 92. t 'Flora foss. Ala sk .,' p, 24.. § ' F lora of Hilin ' (1860), p. 22. II • Bull. de la Soc. Geol. de F ranco,' 2nd ser ., Vol. xxvi , p. 760.

t

C C

J . ST ARKIE GAR D NER ON FOSSIL GRASIlES.

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there are mu ltitudes of forms which p ass int o eac h ot her and puzzle t he b otanist , who is at a loss h ow t o classify t he m in order to obtain goo d species. Even the m ost experienced botanists fin d difficulty in separating th e limit s of t he families of t his extens ive order. Their world-wide di str ibution-for t he y are found on eve n t h e most r em ot e islands-is doub tless du e t o th e enor mous number of individual s, t he h ard nature of their se eds, an d t he avidity with which mi grat ory and ot her b irds feed upon them . Their h ardiness, cap abi lity of resisting immersion in salt water , and power of v egetative r eproduction, would greatly assis t t heir spread. Darwin has proved t hat t he seeds of var io us Graminece which have farinaceous albumen, will bear two or three months immersion in sea water wit h out losing their germinative p ower. " Hence we may assume that the seeds of many almost ubiquit ous sand-binding grasses may be reckoned among those which ar e cast ashore in a vital condition, and we may also a ssume that these grasses are am ong the very first flowering plants to obtain a footing." >II< T hough some spec ies seem t o occupy a relatively r estrict ed area, t he re is n o r eason to suppose t hat an y are geo logicall y ancient. On the ot he r h an d , id en tical spec ies are commo n t o America and Australia. Sporobolus in dicus, R. Br., is one of t hese, " be ing extremely commo n all over Tropi cal an d Su bt r opi cal A sia, Africa, Amer ica, an d Australia, and exten ding to man y islands, including New Z eal and, and to some of t he r em ot e islets, including t he Bermudas. Anoth er species, the S . vir ginicus, is almost universall y spread in maritime districts, in tropi cal and sub-t ro pical r egi ons, an d was one of the few pl ants found in South Trinidad by Si r J oseph Hook er. The grain of these grasses is exceedingly sma ll, that of Sporobolus indicus being about "2"\ th of an inch long and -loth of an inch broad, h ence the me ans by w hich the y may be convey ed from place to plac e are almost in finite." t It is scarcely po ssible t o estimate the influence on the progress and development of t errestrial life that the ap pear ance of grasses was destined to effect . Until they had commen ced to assu me that overwhelming position which they n ow h old in the veget ab le world, scarcely an y progress in the ev olut ion of

*

Hemsley, ' Bot. Chall. Expe d. Introd.,' p. 46. t Hemsley, op. cit. , Pa.rt II, p. 89.

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J. STARKIE GARDNER ON FOSSIL GRASsES.

the Mammalia was possible. Throughout the long agefl of the Trias, the Lias, and Jurassic, the Wealden and the N eocomian, until in fact, the reign of Gymnosperms began definitely to yield before the rising tide of Phanerogams, the diminutive Microlesfes and other probably insectivorous marsupials alone represented the Mammalia. From the Jurassic period until the Eocene, the history of the Mammalia in our European area is a blank, but in America large numbers of them have been described from the late Cretaceous and early Tertiary rocks. They are of a generalised type, with teeth indicating omnivorous habits. Few mammalia are known from the lower Eocenes, and in none, either from the lowest or any stage of the Eocene, are the teeth highly specialised. Vegetable feeders, which, like the hog, tapir, hippopotamus, elephant, rhinoceros, sloth, and members of the ape tribe, find their food in forest and jungle, where there is a mixed vegetation, require very different dentition to those which browse entirely on herbage. Fruits have to be gathered, or picked up, and ground and broken, twigs have to be snapped or wrenched from the trees, roots to be grubbed IIp; and the teeth must be more or less adapted to these varied requirements. The teeth of graminivorous animals, on the other hand, need only to be adapted to the function of cropping and masticating soft herbage. The question is a highly important one, which cannot be properly discussed here. I will only say that I have consulted Prof. Boyd Dawkins and Mr. E. T. Newton, both well-knowu investigators of fossil Mammalia, and they confirm my own impression that there are no Eocene mammals with teeth specialised for grass eating, such as vast numbers of animals are furnished with at the present day, but that in succeeding Tertiary ages they become increasingly modified in this direction. Such evidence as this does ,not, of course, imply that there were no grasses in existence, but it is.at least strongly confirmatory of the view that there were no extensive plains of herbage on which animals could browse. It is, perhaps, hardly necessary to observe that the development of vast numbers of more or less defenceless migratory animals must have given an overwhelming impetus to that of the Carnivora which prey upon them. We are thus brought face to face with a very peculiar condition of things existing to a late stage in the Eocene-an

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FOSSIL GRASSES.

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earth that is either barren, or where verdant, clothed with forest. Such is the conclusion we are irresistibly led to by a study of fossil plants. There were always doubtless patches of swamp and more or less aquatic vegetation, where horse-tails and ferns flourished, and these were joined in due course by rushes and other Monocotyledons. The beds at Bournemouth which I have called" Fern Beds" seem to present such a patch, being apparently a group of herbaceous plants composed of ferns and Monocotyledons, but quite destitute of grasses and dicotyledonous herbs, such as we should expect to meet with under similar circumstances at the present day. For this reason the influence on the habits and development of insect life exerted by the first appearance of grasses must have been prodigious. Until there were grassy glades and flowery meadows, butterflies, the brightest coloured of the beetles, the grasshoppers and bees, in fact all that is most beautiful and charming in insect life, could not have existed. A sudden and brilliant transformation must have taken place when the dull-hued scorpions, spiders, cockroaches, Phasmidca and the many large Ephemera and dragon-flies, the crickets and wood-beetles which infested the weird old cryptogamic forests, ceased to occupy the front rank. This plunges us into the consideration of a subject which could not be done justice to in an entire evening, and to which, indeed, the study of a life might well be devoted. It is one with which I do not feel competent to deal, and I have therefore consulted Mr. Scudder, the Rev. P. B. Brodie, Mr. R. McLachlan, and Mr. Goss, to whom I am greatly indebted for much information. The species of insects that feed wholly or partially on grasses are so numerous that it would be next to impossible to give a list of them. These include, however, definite sections of most of the orders, and it is to the first appearance of genera comprised in these that our attention must be confined. The subject can only be treated very imperfectly here, and it will be impossible to consider how far previously existing genera may have adapted themselves to the new condition of things brought about by the spread of grasses, without undergoing that amount of modification which would confer on them the rank of a new genus; and how far members of families introduced as grass-feeders may have diverged in habit through selecting other kinds of food. It is obvious that the greatest VOL. IX., No.6. 32

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J. STARKIE GARDNER ON FOSSIL GlUSSES.

caution is needed in drawing inferences, but that, with caution, the study of insect life in the past may go far to settle the periods at which the different orders of vegetation respectively made their first appearance in any given area. There is a general agreement that there are no distinct remains of any flower-haunting insects in the Paleeozoic rocks, and their presence would indeed be inexplicable at a period when the entire vegetation was cryptogamic and gymnospermic. The examination that has to be made would be very simple were we able to confine our inquiry to the ancestry of such insects as generally frequent the wind-fertilised Graminero. These are, according to letters I have received from Mr. Scudder, only Thripsidro, Sipphidro, and occasionally some Halidus-like Hymenoptera, of the occurrence of which, in pre-Tertiary times, there are no authenticated instances. But in order to sustain the contention that there could have been no meadows previous to the appearance of grasses, a much more extended examination is necessary. The appearance of no order is more interesting in connection with this subject than that of the Lepidoptera. These may be divided roughly into Moths and Butterflies. The former are adapted to a much wider range of circumstances than butterflies, and many have their habitat in woods and forests, and could exist without any open spaces. Even the most distinctly woodland butterflies, on the other hand, frequent rather the open glades or the tree-tops than the shades of the forest. The celebrated Stonesfield butterfly has been shown by Mr. Scudder* to be a Oicada, and there is now no evidence of the occurrence of that section of Lepidoptera prior to the Eocene. In a paper by Oppenheim, just published in the 'Berliner Entomologische Zeitschrift,' VoL xxix, there isa figure (pI. 11, fig. 7) of an insect from the Jurassic of Solenhofen with the coiled, tubular flower-probing, sucking apparatus of the Sphingidro. It has been known for some time, and perhaps presents, on the whole, the clearest direct evidence we have of the presence of definite angiosperms at that date. t It and its allies are the only known Mesozoic Lepidoptera, and form a remarkable exception to the rule that flower-visiting insects are either absent or very poorly represented in pre-Tertiary deposits (Scudder, in litt.). Butter• "Fossil Butterflies," 'Mem. Amer. Assoc. for the Advane- of Sci.,' 1875, p.90. t At least one species of Sphinx is said to live on Pines, so that the evidence is not perhaps so definite as could be desired.

J. STARKIE GARDNER ON FOSSIL GRASSES.

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flies form one of the clearest possible tests as to whether flowery meadows existed, and we find them wholly absent until the Upper Eocene beds of Aix, in Provence, are reached. Always rare, and absent from some of the most extensive series of insects of even later age, it is not a little remarkable that three of the five species from Aix belong to genera whose larvte are almost exclusively graminivorous, so much so that Mr. Scudder entertains no doubt that they lived upon the grasses with which they are associated. Mr. A'Court Smith, in letters to me, claims to have many specimens of butterflies from Gurnet Bay. The presence of Lepidoptera is to be inferred, even where their remains have not been met with, in some other deposits, from the occurrenee of HemiteZes and other caterpillar-eating ichneumon-flies. The Hymenoptera are less distinctly anthophilous. Mr. Brodie thinks there may be traces of them in the Lias, among his undescribed specimens. One figured by Heel', of this age, must be dismissed as more than doubtful, and it is again the Upper Oolite of Solenhofen that contributes the earliest definite examples. Mr. Scudder says: "One may speak even more confidently of the Hymenoptera. The only Mesozoic forms known are some very obscure objects, upon which it would be rash to base any definite oonolusions, with the exception of three fragments of clearly defined wings, which have been considered, and probably are, ants-a group in only a narrow sense anthophilous " (in Zitt.). They do not reappear till the Middle Eocene. Mr. Brodie tells me that both Bees and Ants are very abundant in the Gurnet Bay Beds. The Anthophorites of Oeningen, Radaboj, and Anvergne are Bees whose habits would presuppose the existence of meadows. Among the Hemiptera, Mr. Scudder informs me that he believes only the Thripsidre, the Capsidre, and some of the smaller LygacidCE are found abundantly on flowers, " and all these groups are absent from rocks earlier than the Tertiaries, unless we include in the last-mentioned two or three imperfect and obscure wings from the English Purbeck which have been referred to them." Mr. Scudder's remarks on Diptera are also of especial interest. " The SyrphidCE, the EmpidCE, and the Muscidce are distinctively the anthophilous families of Diptera, and of these we have not one clear instance, since the Hasmona Leo of Giebel is certainly not a true Empis, and the two or three others which have been referred to these groups can only remain in them out of

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J. STARKIE GARDNER ON FOSSIL GRASSES.

courtesy, for they are too obscure to warrant any confidence of statement whatever. The same may be said of the other groups of Diptera which frequent flowers to a less extent, such as oneor two Asilidos. Most of the Mesozoic Diptera were Nemaiocera. With regard to the Orthoptera, very many are Palseozoic, including the cockroaches, crickets, and Phasmas. True locusts occur in the Lias and Purbeck, and a large number of Orthoptera have recently been described by Mr. Scudder from the Rev. P. B. Brodie's collection. Magnificent species have been met with at Solenhofen, N early all grasshoppers are grass-feeders, but it is doubtful whether their remains in the fossil state can be separated from the Locusta, which eat everything in the form of vegetation that lies in the course of their migrations. Mr. A'Court Smith relates the discovery of a mass of stone about 5 feet long, 9 inches wide, and afoot thick, which he describes as composed of Locusts, except a thin band of vegetable remains resembling willow catkins, the stone merely cementing them together. It is a matter of the greatest regret that the specimen was not preserved entire, only a few fragments in fact having been saved. Grasshoppers or Locusts are frequently represented associated with plants in Unger's works on the Austrian Tertiaries. Coleoptera are barely represented in the Paleeozoio rocks. They are common in the Lias and Purbeck, most of them being referred by Brodie and Westwood to wood-, and low marshhaunting, genera. Mr. Scudder thinks these should be reexamined. Heel' has tabulated 116 beetles from the Swiss Lias, dividing them into 16 families. Scudder remarks that "considerably more than half the species belong to the Buprestidce, Carabidce, or some family of water-beetles, none of which can be looked on as anthophilous; and the only groups present in any abundance which could be so regarded are the Elateridoi and Nitidulida3, to which are referred respectively 10 and 7 species." The remains of beetles are scattered throughout most of the Tertiary strata, and manifest, according to Heel', a great increase in the number of pastureand flower-haunting types. Among them may be instanced the genera Onthophagus and Geotropus, found at Oeningen and Aix" whose domestic economy requires respectively the presence of cow-, and of horse-dung, and therefore of grass-feeding ., Oustalet, 'Recherches sur les inaectes fossiles des terrains tertiaires de la France,' Part 2.

J. STARKIE GARDNER ON FOSSIL GRASSES.

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mammalia and supplies of grass. Among the direct graminivores at Oeningen - are a Donacia near to D. menyanthidis, which lives upon Phragmites communie and P. aruruiinaria ; ChTysumela calami, resembling C. graminis; and Clytra pandorai, which it is to be inferred lived on clover. Erirhinu« scirpi possessed, according to Oustalet, an ancestral form at Aix, which probably lived on Cyperites; another beetle like Hydronomus alismatis may equally have lived on Alismacites, and a species of Oassida it is allowable to suppose would have lived on thistles and other composites. Mr. Scudder concludes that anthophilous insects were comparatively rare in pre-Tertiary times, but did exist. It should not be forgotten, he remarks, that our knowledge of Mesozoic insects of any kind is exceedingly meagre, and that we do not know a dozen insects from the Cretaceous; nor that the moment we touch the Tertiaries (or rather the Oligocene-for Eocene insects are rare enough) we come on a profusion of lile which can only be compared to the present insect-fauna of warm countries in variety and development of type. Indeed the Oligocene is practically an integral part of the present in its insect life. We have indications of the same diversity-in habits and peculiarities-when we find almost every existing family and a fair number of aberrant types, such as a strepsipterous insect and the triangular larva of a meloid, to mention only Ooleoptera. The anthophilous groups of insects were here so fully developed, moreover, that we are almost forced to believe that they had a considerable development in at least late Mesozoic times. Thus the Syrphidm-the best example of anthophilous insects among the Diptera-were abundant and varied, nearly 50 species being already indicated in the Oligocene, belonging to a considerable number of genera, 'several at least of which are dominant types to-day. Quitting the insects, the final conclusions, at which we are able to arrive, may be summarised as follows: Jointed stems and sword-like leaves, which might possibly have belonged to arborescent (lramincos, occur in Mesozoic rocks from the Lias upward. There is no evidence as to what tribes these may have belonged to, beyond the most superficial resemblance, and their vestiges are exceedingly rare. No leaf possessing definite characters of the Gramine» has yet been met with, older than the Middle Eocene period. No

*

'Die Insekten-fauna von CEningen und Radaboj,' Leipzig, 1847.

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J. STARKIE GARDNER ON FOSSIL GRASSES.

seed or flower-spike referable to the Graminece is known of earlier age than Upper Eocene, unless it be in the Tertiaries of Spitzbergen, which are at present of uncertain age. The stations and habits of grasses are such that it is most improbable, had they existed in any quantity, that all traces of them would have escaped preservation in beds formed under such conditions as those of the Lower and Middle Eocenes of this country. The evidence of animals and insects supports the view that herbaceous grasses at least were absent or rare even in the Middle Eocene period. With the evidence before us we are justified in believing that grasses first became a prominent element in the floras of both hemispheres towards the close of the Eocene, but it is by no means improbable that they were established in Spitzbergen at an earlier period. It is impossible, on the palesontological evidence, to hazard any opinion as to the lines through which the Graminece were developed. The little known appears to indicate that in temperate latitudes the arborescent tropical forms preceded the herbaceous forms, and the latter would therefore be degenerate types, but in view of the possible higher antiquity of the Spitzbergen deposits, this inference may be entirely fallacious or at best apply only to certain areas. When once developed, peculiarities of growth and structure enabled them to spread with astonishing rapidity and to compete successfully with all other plants in a great variety of stations. We may recall, however, that they were preceded in remote times by the Pandaneos and more immediately by Typhacece, a group which some families of Gluanaceai somewhat resemble. The introduction of an aggressive type in vast numbers, and of habit different to that of pre-existing vegetation, exerted an influence on terrestrial life that is without parallel, the immediate effects of which were :-the development of meadows and prairie vegetation as distinct from that of marsh, scrub, and forest; the introduction of vast herds of grazing mammals, as distinct from the herbivorous mammals previously existing and of the larger kinds of Carnivora which prey on them; the introduction of meadow insects, distinct from aquatic and woodland forms, including butterflies, bees, and grasshoppers, &c. ; and lastly the introduction of a food-supply, both animal and vegetable, in the absence of which it is doubtful whether man himself would have been enabled to reach his present stage of development.