- Email: [email protected]
Lobostemon daltonii (Boraginaceae): a new species from the Western Cape, South Africa
144
S. M r. J. Bol. 1999.65(2) 144-1 48
Lobostemon daltonii (Boraginaceae): a new species from the Western Cape, South Africa Matt H. Buys' and J.J.A. van der Walt Department of Botany, University of Stellenbosch, Private Bag X1 , Matieland , 7602 Rep ublic of South Africa Received 03 June 1998; revised J9 Augus{ 1998
A new species of Lobostemon Lehm. (Boraginaceae), placed in the section Fruticosi Levyns, is described from Cape Infanta region in the Western Cape, South Africa . Illustra tio ns of the macromorphology, indumentum, stigma and sty le, fru it as well as a distribution map. are provided. Keywords : Boraginaceae, Lobostemon daltoni!, new species, sect. Fruticosi.
-To whom correspondence should be addressed. Present address . AP. Goossens Herba rium, Departmen t of Plant and Soil Sciences, Potchefstroom University for CHE , Private Bag X6001, Potchefstroom , 2520 South Africa . (E-mail: [email protected]) .
Introduction
TYPUS :~W estern
Lehm. , with about 30 species, is th e largest genus in the south ern A fri can Boraginaceae. This endemic ge nu s is mainly confined to the winter-rainfall area of South A fri ca, occu rring frolll S prin g bok to Mossel Bay, and further eastward along the coast to abou t Grahamstown, where th e rain occ urs through out the year. Limited numbers of species exhibit a wide di stribution range with the norm , however, tending to be highly locali sed di stributions. Margaret Levyns last intensive ly studied Lob oslemon in 1934. Extensive fieldwork was undertaken in the Bredasdorp-Cape Infanta area as part of a current systematic revi sion of th e genus. During this time a Loboslemon species, no t co nforming to any known taxon , was brought to our attention by Nick O 'A lto n. As a resu lt, the new species Lobos!emoll dallonii M .H. Buys is described and named in recogniti o n of Nick D 'A lton 's fri en dl y ass istance during many visits to his farm .
road, between Swellendam and Infanta, between turnoff to BalIyfor and 7 km beyond (- BD), 1993- 10-21 , M.H Buys 50}
LohoSlefl1()II
Materials and Methods A ll the materi al used in the study was collected during the peak fl owerin g season, i.e. between August and October. At least five leaves were studi ed anatomically. Transverse section s of wax-embedded laminae were cut with a rotary mi crotome and stained with a mi xture of Safranine 0 an Aleian green (Joel
1983). Sections were taken through the middle of the laminae. The stigma and leaf indumentum were studied with a Joel scanning el ec tro n mi croscope (SEM), using secondary-electron detect ion and an acceleration voltage of 4-5 kY. The outer surfaces of the m eri carpids and sepal indumentulll were stud ied with a Philips XL30DX-4i SEM, using an accelerati on vo ltage of 10 kV. Fres h material for observation in the SEM was d ri ed using the CRYO method (Robards & Wilson 1993). Macromorpho logica l studies were do ne in the fi eld as well as from herbarium and conse rve d spec imens.
Species treatment LobostemoJl daltonii M.H. Buys, sp. nov. In sectione Frulieosi. Frutex tlorulentus. Folia sessilia, a lterna , ovata ad obovata, utrimque inaequaliter pilosa, margine integra. Corola violacca vel azurea, infundibularis, subreguiari s, extra puhescens. Stam in a primo inclusa, demum exserta, epipetaiosa, squamuli s sta minalibus parvulis. Fructus schizocarpus, quadripartitlls. in late ribu s tubercu latus.
L. 'rigoro affinis sed indumento apicurn sepalorum et praesertim sepal is recu rvis differt.
Cape, 34"25'S 20' 4 7'E (R ive rsdale): On the
(PRE, holotypus; K, MO. isotypus).
Description (Figure 1) Perennial , resproutlng shrub_ 600- [000 ll11ll high. Branches alternate, cau[ous, antrorst:, herbaceous brancht:s sparsely hairy, woody branches glabrescent. Leaves simple, scss ih.:. coriaceolls, exstipulate, cauli ne to acroramous. alternate. tran svcrsdy n;curved (especially the basal leaves) to inc urved. longitud inally straight, dead basal leaves not persistent. ovate to ohovatc. (9- ) 10- 18 (-2 0) x (4-) 5-9 (-II) mm , adaxially mostly sparsely. bu t sometimes copiously hairy. if sparsely hairy then not even ly sprl.!ad. bm largely confi ned to marg in, apex and mid-vein. abaxi ally mostly sparsely, but somet imes copiously hairy. if sparsely ha iry then not evenly spread . but largely confined to margi n, apex and mid-ve in. indumcntum spinolls. hairs similar in length: with sta lked g landul ar and unhranehed simple and pustular trichomes: It:a1' margin ent ire : apex acute or oblu se: il.!af mid -vein not prominent abaxially. Illjlorescence n cincinllus. appearing as compound scorpio id cy mes. terminal. young flO\vering axis elongated. with the tlower buds arranged in two distinct parallel rows, spreading greatly in fri.liting stagc. Brnc!s (5- ) (6- 10) (-11) x (1.5- ) 2- 5 (-6) mrn. lanceo late to ovate, induln cntull1 as for leaves. Flowers mt:dium sized (corolla 15- 25 mill long), more than three per cymulc, obliquely zygomorph ic. dichl amyd~ous, in fundibular, connate below to form a corolla tub c. Sepals 5. lanccolate, half to more than half of corolla ll.!ngth. di ssimilar in width. tree. adaxially and abaxially copiously hai ry: yOllng ap ices mostly rccurved, with brow n g landular trichomes all thc adax ial sur face . Petnls 5. uissim ilar, th e Iwo anterior petal lobes largl:1" than the rcst. posteri or petals c. 20-21 mm long. posterior petal l o b~s c. 5- 6 mm lo ng. an terior peta ls c. 22.5- 23 mm long. anter ior p~ t a l l nhcs c. &-7 mill long. predominantl y vi olet-blue. abaxially hai ry. hairs evenl y spn:ad. tu be adaxially spa rsely ha iry at poi nt of attachment. SlamellS 5. apostemonous, ep ipcta lolls. fil antherous. dissimil ar in length, exscrted in adu lt flowers; anthers dorsi fixed; fil ament s shortly adnate «5 mm) above stam inal scales, glabrous. Staminal scales present . located 3 mm above the bast: of the corolla tube. not inserte d at the entrance of the cylindrical portion of the coro lla lu be. n;duced to ridges. without lateral lobes. vi llous. area between scak s al so hairy. Cynoecillnl 2-carpel1ed; ovary superior. 4-locul ar (via false septa), neetariferous: disc present. longitudinally tlat. lransverse ly 4-angled; style gynobasic, {erete, hairy in the med ian sectioll s: stigma minutely bilobed. Fruit schizocarpous. deep ly 4-parted into I- ~~e ded meriearp ids: meriearpid of tht: ridge type. more or less sym metrical. generall y 13 maturing, ovo id-trigontls: apex beak-l ike. straight: latera l p
S. Aft'. J. Bot. 1999, 65( I)
145
R
~---'-" I
Figure I L. daltonii. A. Young inflorescence: B. Flowering branch: C. Dissected sepa ls: D. Di ssected pt.::tals: E. Young flower bud . Scale bar for A & B = I () mm: for C. 0 & E = 20 mm.
S . Atr. 1. Bot. 1999, 65(2)
146
Figure 2
Indulllcntum of the leaf margin of L. dailOnii.
Figure 4
Multicellu lar, g landu lar tri chomes on adaxial sepa l
apices of L. dalton/ i. tuherculate, tubercles with a smooth apex, ridges reduced; dorsal side tuberculate, acute, keel wanting; ventral side tuberculate, convex, keel wanting; cicatrix triangular, concave.
Specimens studied - 3420: Potberg, Brccde River side (- Be), H. David S.n. sub PRE 4J()/7 (PRE): Potbag, Breede River side. (- Be), H David S.n. sub NBG 45386 (NBG); Potberg, Breede River side (- BC). H. David S.n. sllb NBG 45388 (NBG); Potbcrg, Brt:ede River side (-Be), If. David s.n sub STE 31998 (STE): Cape Infanta, about 3 km north o1'towl1 (-BO). J.HJ Vlok J 7(}9 (STE): Brcede River, near mouth of river (BD). AIR. Levyns 8372 (I30L): On the road between Swellendam and infanta, betwt:en turnoff to Ballyfor and 7 km beyond (-BD), MH. Buys 501 (PRE) . Leaf anatomy Leaves isobilateral; amphistornatic, with the greatest number of stomata abaxially. Cuticle relatively thick, smooth. Epidermis cells relatively small, outer periclinal walls thickened; trichomes adaxially and abaxially, or glandular. Mesophyll differentiated into two layers palisade parenchyma adaxially and abaxially; hypodermis at the leaf margins and adaxial and abaxial to the midvein; collenchyrna adaxial and abaxial to the rnidvein; phenolic compounds scattered throughout the mesophyll. Vascular bundles enclosed in parenchymatous bundle sheaths.
Figure 3 L. daltonii.
Indumentum of the sepals and petals in a flower bud of
Indumentum The leaf indumentum is chiefly spinous, comprising either simple or pustular, appressed trichomes. These trichomes have a smooth texture (Figure 2). Scattered stalked glandular trichomes occur on both leaf surfaces. The indumentum of the herbaceous stems are similar to those of the leaves. Woody stems become glabrous with the development of cork. The indumentum of the flowers, particularly the sepals, deserve special mention. The flower buds of L dalfollii seem preoccupied in deterring unwanted visitors in that a rich pro fusion of glandular as well as non-glandular trichomes occur on the sepal and petal surfaces (Figure J). The glandular, multicellular trichomes (Figure 4) are borne exclusively on the adaxially surface of the recurved sepal apices. The non-glandular trichomes are largely confined to the abaxial petal, and ab- and adaxial sepal surfaces. Stigma and style The stigmas produce no observable exudate and are, therefore, regarded as being dry. The receptive cells are concentrated in distinct zones or heads (Figure 5). The stigma of L dallol1ii is bilobed, (or at best possesses high ly reduced stigma branches) in that only the stigmatic region is free with the rest of the two carpels being fused. The surface of the stigmas in L. daltonii is distinctly papillate, with the papillae being of a unicellular nature.
Figure 5
The stigma of L. daltonii.
s. Afr. J.
Figure 6
Bot. 1999. 65( I)
147
Figure 7
Lateral vit:w ofa L d,,/1ollii mcricarpid.
These characters conform to those found in the majority of Loboslemoll species as well as to those found by Hes l o p~H arri· so n and Shiv31l1l3 ( 1977) in EclriulI1 L. and most of the other Boraginaceous taxa.
Fruit morphology The gynoeciu1l1 o f Loh()Sf~I/IOII is two carpelled, resulting in two mericarps with ripen ing. However, th e two mericarps each become two- loc ular as a result of false septa. forming fo ur mericarp ids (Hil ger 1985 & pers. COI11.) Th e tuberculate mericarpid s of Lubas/emoll daltoni; belong to Se ibert's (1978) 'Hockerform' group. Buys and Van del' Walt (J 996) designate the co rrespond-
ing term to be 'ridge-type' (Figure 6 and 7), Taxonomic note The first collection made of L. da/follii is that of Levyns 83i2 (BOL) in 1947 , identified to be L. Irigal/lls (Thunb.) H. Buek, a lso a member of the section Frulicosi. However. L dalfon;; dif· rers from the latter in that its leaves are distinctly coriaceous and the basal leaves especia ll y are tran sversely incurved as opposed to th e he rbaceous leaves in genera l and the incurved basal leaves of /. Il"IgOlIllS in the vicinity of /. dal/onii. A form of L frigolllfs
Ventral view o f a L dallonii mcricarp id.
occurring chiefly near Port Elizabeth does possess coriaceous leaves, but here the orientation of the leaves are transversely incurved. In addition , the young sepal apices of L da/toni; are mostly rec urved with a distinct brown glandular pubescence 0 11 the adaxial surface, whereas in L. Irigo1'llis the young sepal apices are incurved·applanate, with the pubescence being less di st inct in nature . The maj o rity of fl ower buds in L. da/tonii as opposed to L. IrigoHIIs, often appear to possess only four sepals. The fifth sepal in the former case is ens hrouded by the remaining four sepal s (Figure I E). A preliminary cladistic analy sis of secti on Fnrticosi resulted in a poorly resolved clade. A di sclIssion of affini ties is purel y speculative until additional data is fo rth com ing. A lthough L. dol· lOnii may have some affinity to L. trigolll/s, the Fonner shares the presence of coriaceo us leaves, hairs spread unevenly on the adaxial leaf surfaces and an often obtuse leaf apex with L. colli· n1ls C. H. Wrigh t, wh ich also belongs to sect io n Fruticosi. However, L. daltonii differs from L collimrs in possessing recurved sepal apices and fl ower bud s arranged in two di stin ct rows. L collil/lls possesses loosely arranged fl ower bud s and appl a nate sepal apices. Furthermore, L daltonii fl owers mainly in Spri ng, while L. collinus fl owers chiefl y in Autu mn.
HEIGHT ABOVE SEA LEVEL
c:J Over 1500 m 32"S-+-\--,,!, ~~~~-~~~~~1--~~--i1~~~~t-----~~~~~~~~-~ 900.1500m
20
22"E
~.
Figure 8
KlHml1 distribution of L. daltonil .
23'
,.'
".
,.'
0
20
~o
".
EO 80
'OO ~m
"
S. An·. J. Bot. 1999,65(2)
148
Ecology and distribution L. da/tonii fl owe rs ma in ly from October to November. It is restricted in its distri bution, being found excl usive ly near Cape Infan ta (Figu re 8), preferring the loamy soils in the tra nsition
Afr . J. Bot. 62( I): 31 - 35. HES LOP-HARR ISON. Y. & S HIRVANNA, K.R. 1977. The recepti ve
s urface of the Angiospenll sl ig ma ..·II1II. Hut. 4 1: 1 233 - 1 25~. HILGER. H.H. 1985 . On logen ie. Morphulogil.! lilld systematischc
zone between Mountain Fy nbos (Rebelo 1996a) and South and
Bedeu tung gcflUgelter und gloclHltlictltragcndcr Cynoglossseae - und
South-west Coast Ren osterveld (Rebelo 1996b). Collections of L. dallonii have been few and far between, totalling four collectors with th e present revision. Th is could be indicative o f the rel-
Erilricheae-Frilchtc (Borag inaccac). BOI. JlIhl'b. SI'SI. IOS(3): 323-
ative remoteness of the locality . The precise number of
individuals is currently unknown, although the impression obtai ned during field work is that there are a sufficient number
378. JOEL D.M. 1983. AGS (Akian Green Sat'nlllin). a simpk difkrenlial
staining of platH material It)!' the light mil:roscope . Proc. RMS 18: 149- 151.
present, not withstanding the overall restricted distribution range.
REBELO, A.G . 1996a. Mountain Fynhos. In: Vegt.:tation of South
Additional field work is required to determine the precise co nservation status of the species.
Africa, Lesotho and Swaziland. (cds.) A.B. Low. & A.G. Rebelo.
Acknowledgements We thank the Foundati on for Researc h Development and the Univers ity o f Stellenbosch for fin ancial Sllpport. References DUY S. M.II. & VAN DER WA LT. J.J.A. 1')96. A ncw spL'c ics of I.ohosfelllon sect ion Gmndiflori (Boraginaceae) from South Ali·iea. S.
Dept. Environmental Affairs & Tourism. Pretoria. REBELO, AG . 1996h. South and SOllth-w~sl Coast Renosterve kl. In :
Vegetation o f South Africn.
L~so t ho
anti S\\'nzi lnnd. (ed::;.) A.R Lm\
& A.G. Rebelo. Dept. Environmcntal Afl ilirs & Tou rism. Pretoria. ROBARDS. A.W. 8: WII.SON. A.J. 11)1):;. Proced ures in EleCl ron
Microscopy. Wiler 8: Sons. N~\\' York. SE I BERT, J. 1978. Fruch tan;Jlmni sehe Ulllcl':->lIdlllllgcn all I.ilhospcrmeac (Boraginaccae) Di.IT BOl . .... : 1- 207 .
S. M r. J. Bol. 1999.65(2) 144-1 48
Lobostemon daltonii (Boraginaceae): a new species from the Western Cape, South Africa Matt H. Buys' and J.J.A. van der Walt Department of Botany, University of Stellenbosch, Private Bag X1 , Matieland , 7602 Rep ublic of South Africa Received 03 June 1998; revised J9 Augus{ 1998
A new species of Lobostemon Lehm. (Boraginaceae), placed in the section Fruticosi Levyns, is described from Cape Infanta region in the Western Cape, South Africa . Illustra tio ns of the macromorphology, indumentum, stigma and sty le, fru it as well as a distribution map. are provided. Keywords : Boraginaceae, Lobostemon daltoni!, new species, sect. Fruticosi.
-To whom correspondence should be addressed. Present address . AP. Goossens Herba rium, Departmen t of Plant and Soil Sciences, Potchefstroom University for CHE , Private Bag X6001, Potchefstroom , 2520 South Africa . (E-mail: [email protected]) .
Introduction
TYPUS :~W estern
Lehm. , with about 30 species, is th e largest genus in the south ern A fri can Boraginaceae. This endemic ge nu s is mainly confined to the winter-rainfall area of South A fri ca, occu rring frolll S prin g bok to Mossel Bay, and further eastward along the coast to abou t Grahamstown, where th e rain occ urs through out the year. Limited numbers of species exhibit a wide di stribution range with the norm , however, tending to be highly locali sed di stributions. Margaret Levyns last intensive ly studied Lob oslemon in 1934. Extensive fieldwork was undertaken in the Bredasdorp-Cape Infanta area as part of a current systematic revi sion of th e genus. During this time a Loboslemon species, no t co nforming to any known taxon , was brought to our attention by Nick O 'A lto n. As a resu lt, the new species Lobos!emoll dallonii M .H. Buys is described and named in recogniti o n of Nick D 'A lton 's fri en dl y ass istance during many visits to his farm .
road, between Swellendam and Infanta, between turnoff to BalIyfor and 7 km beyond (- BD), 1993- 10-21 , M.H Buys 50}
LohoSlefl1()II
Materials and Methods A ll the materi al used in the study was collected during the peak fl owerin g season, i.e. between August and October. At least five leaves were studi ed anatomically. Transverse section s of wax-embedded laminae were cut with a rotary mi crotome and stained with a mi xture of Safranine 0 an Aleian green (Joel
1983). Sections were taken through the middle of the laminae. The stigma and leaf indumentum were studied with a Joel scanning el ec tro n mi croscope (SEM), using secondary-electron detect ion and an acceleration voltage of 4-5 kY. The outer surfaces of the m eri carpids and sepal indumentulll were stud ied with a Philips XL30DX-4i SEM, using an accelerati on vo ltage of 10 kV. Fres h material for observation in the SEM was d ri ed using the CRYO method (Robards & Wilson 1993). Macromorpho logica l studies were do ne in the fi eld as well as from herbarium and conse rve d spec imens.
Species treatment LobostemoJl daltonii M.H. Buys, sp. nov. In sectione Frulieosi. Frutex tlorulentus. Folia sessilia, a lterna , ovata ad obovata, utrimque inaequaliter pilosa, margine integra. Corola violacca vel azurea, infundibularis, subreguiari s, extra puhescens. Stam in a primo inclusa, demum exserta, epipetaiosa, squamuli s sta minalibus parvulis. Fructus schizocarpus, quadripartitlls. in late ribu s tubercu latus.
L. 'rigoro affinis sed indumento apicurn sepalorum et praesertim sepal is recu rvis differt.
Cape, 34"25'S 20' 4 7'E (R ive rsdale): On the
(PRE, holotypus; K, MO. isotypus).
Description (Figure 1) Perennial , resproutlng shrub_ 600- [000 ll11ll high. Branches alternate, cau[ous, antrorst:, herbaceous brancht:s sparsely hairy, woody branches glabrescent. Leaves simple, scss ih.:. coriaceolls, exstipulate, cauli ne to acroramous. alternate. tran svcrsdy n;curved (especially the basal leaves) to inc urved. longitud inally straight, dead basal leaves not persistent. ovate to ohovatc. (9- ) 10- 18 (-2 0) x (4-) 5-9 (-II) mm , adaxially mostly sparsely. bu t sometimes copiously hairy. if sparsely hairy then not even ly sprl.!ad. bm largely confi ned to marg in, apex and mid-vein. abaxi ally mostly sparsely, but somet imes copiously hairy. if sparsely ha iry then not evenly spread . but largely confined to margi n, apex and mid-ve in. indumcntum spinolls. hairs similar in length: with sta lked g landul ar and unhranehed simple and pustular trichomes: It:a1' margin ent ire : apex acute or oblu se: il.!af mid -vein not prominent abaxially. Illjlorescence n cincinllus. appearing as compound scorpio id cy mes. terminal. young flO\vering axis elongated. with the tlower buds arranged in two distinct parallel rows, spreading greatly in fri.liting stagc. Brnc!s (5- ) (6- 10) (-11) x (1.5- ) 2- 5 (-6) mrn. lanceo late to ovate, induln cntull1 as for leaves. Flowers mt:dium sized (corolla 15- 25 mill long), more than three per cymulc, obliquely zygomorph ic. dichl amyd~ous, in fundibular, connate below to form a corolla tub c. Sepals 5. lanccolate, half to more than half of corolla ll.!ngth. di ssimilar in width. tree. adaxially and abaxially copiously hai ry: yOllng ap ices mostly rccurved, with brow n g landular trichomes all thc adax ial sur face . Petnls 5. uissim ilar, th e Iwo anterior petal lobes largl:1" than the rcst. posteri or petals c. 20-21 mm long. posterior petal l o b~s c. 5- 6 mm lo ng. an terior peta ls c. 22.5- 23 mm long. anter ior p~ t a l l nhcs c. &-7 mill long. predominantl y vi olet-blue. abaxially hai ry. hairs evenl y spn:ad. tu be adaxially spa rsely ha iry at poi nt of attachment. SlamellS 5. apostemonous, ep ipcta lolls. fil antherous. dissimil ar in length, exscrted in adu lt flowers; anthers dorsi fixed; fil ament s shortly adnate «5 mm) above stam inal scales, glabrous. Staminal scales present . located 3 mm above the bast: of the corolla tube. not inserte d at the entrance of the cylindrical portion of the coro lla lu be. n;duced to ridges. without lateral lobes. vi llous. area between scak s al so hairy. Cynoecillnl 2-carpel1ed; ovary superior. 4-locul ar (via false septa), neetariferous: disc present. longitudinally tlat. lransverse ly 4-angled; style gynobasic, {erete, hairy in the med ian sectioll s: stigma minutely bilobed. Fruit schizocarpous. deep ly 4-parted into I- ~~e ded meriearp ids: meriearpid of tht: ridge type. more or less sym metrical. generall y 13 maturing, ovo id-trigontls: apex beak-l ike. straight: latera l p
S. Aft'. J. Bot. 1999, 65( I)
145
R
~---'-" I
Figure I L. daltonii. A. Young inflorescence: B. Flowering branch: C. Dissected sepa ls: D. Di ssected pt.::tals: E. Young flower bud . Scale bar for A & B = I () mm: for C. 0 & E = 20 mm.
S . Atr. 1. Bot. 1999, 65(2)
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Figure 2
Indulllcntum of the leaf margin of L. dailOnii.
Figure 4
Multicellu lar, g landu lar tri chomes on adaxial sepa l
apices of L. dalton/ i. tuherculate, tubercles with a smooth apex, ridges reduced; dorsal side tuberculate, acute, keel wanting; ventral side tuberculate, convex, keel wanting; cicatrix triangular, concave.
Specimens studied - 3420: Potberg, Brccde River side (- Be), H. David S.n. sub PRE 4J()/7 (PRE): Potbag, Breede River side. (- Be), H David S.n. sub NBG 45386 (NBG); Potberg, Breede River side (- BC). H. David S.n. sllb NBG 45388 (NBG); Potbcrg, Brt:ede River side (-Be), If. David s.n sub STE 31998 (STE): Cape Infanta, about 3 km north o1'towl1 (-BO). J.HJ Vlok J 7(}9 (STE): Brcede River, near mouth of river (BD). AIR. Levyns 8372 (I30L): On the road between Swellendam and infanta, betwt:en turnoff to Ballyfor and 7 km beyond (-BD), MH. Buys 501 (PRE) . Leaf anatomy Leaves isobilateral; amphistornatic, with the greatest number of stomata abaxially. Cuticle relatively thick, smooth. Epidermis cells relatively small, outer periclinal walls thickened; trichomes adaxially and abaxially, or glandular. Mesophyll differentiated into two layers palisade parenchyma adaxially and abaxially; hypodermis at the leaf margins and adaxial and abaxial to the midvein; collenchyrna adaxial and abaxial to the rnidvein; phenolic compounds scattered throughout the mesophyll. Vascular bundles enclosed in parenchymatous bundle sheaths.
Figure 3 L. daltonii.
Indumentum of the sepals and petals in a flower bud of
Indumentum The leaf indumentum is chiefly spinous, comprising either simple or pustular, appressed trichomes. These trichomes have a smooth texture (Figure 2). Scattered stalked glandular trichomes occur on both leaf surfaces. The indumentum of the herbaceous stems are similar to those of the leaves. Woody stems become glabrous with the development of cork. The indumentum of the flowers, particularly the sepals, deserve special mention. The flower buds of L dalfollii seem preoccupied in deterring unwanted visitors in that a rich pro fusion of glandular as well as non-glandular trichomes occur on the sepal and petal surfaces (Figure J). The glandular, multicellular trichomes (Figure 4) are borne exclusively on the adaxially surface of the recurved sepal apices. The non-glandular trichomes are largely confined to the abaxial petal, and ab- and adaxial sepal surfaces. Stigma and style The stigmas produce no observable exudate and are, therefore, regarded as being dry. The receptive cells are concentrated in distinct zones or heads (Figure 5). The stigma of L dallol1ii is bilobed, (or at best possesses high ly reduced stigma branches) in that only the stigmatic region is free with the rest of the two carpels being fused. The surface of the stigmas in L. daltonii is distinctly papillate, with the papillae being of a unicellular nature.
Figure 5
The stigma of L. daltonii.
s. Afr. J.
Figure 6
Bot. 1999. 65( I)
147
Figure 7
Lateral vit:w ofa L d,,/1ollii mcricarpid.
These characters conform to those found in the majority of Loboslemoll species as well as to those found by Hes l o p~H arri· so n and Shiv31l1l3 ( 1977) in EclriulI1 L. and most of the other Boraginaceous taxa.
Fruit morphology The gynoeciu1l1 o f Loh()Sf~I/IOII is two carpelled, resulting in two mericarps with ripen ing. However, th e two mericarps each become two- loc ular as a result of false septa. forming fo ur mericarp ids (Hil ger 1985 & pers. COI11.) Th e tuberculate mericarpid s of Lubas/emoll daltoni; belong to Se ibert's (1978) 'Hockerform' group. Buys and Van del' Walt (J 996) designate the co rrespond-
ing term to be 'ridge-type' (Figure 6 and 7), Taxonomic note The first collection made of L. da/follii is that of Levyns 83i2 (BOL) in 1947 , identified to be L. Irigal/lls (Thunb.) H. Buek, a lso a member of the section Frulicosi. However. L dalfon;; dif· rers from the latter in that its leaves are distinctly coriaceous and the basal leaves especia ll y are tran sversely incurved as opposed to th e he rbaceous leaves in genera l and the incurved basal leaves of /. Il"IgOlIllS in the vicinity of /. dal/onii. A form of L frigolllfs
Ventral view o f a L dallonii mcricarp id.
occurring chiefly near Port Elizabeth does possess coriaceous leaves, but here the orientation of the leaves are transversely incurved. In addition , the young sepal apices of L da/toni; are mostly rec urved with a distinct brown glandular pubescence 0 11 the adaxial surface, whereas in L. Irigo1'llis the young sepal apices are incurved·applanate, with the pubescence being less di st inct in nature . The maj o rity of fl ower buds in L. da/tonii as opposed to L. IrigoHIIs, often appear to possess only four sepals. The fifth sepal in the former case is ens hrouded by the remaining four sepal s (Figure I E). A preliminary cladistic analy sis of secti on Fnrticosi resulted in a poorly resolved clade. A di sclIssion of affini ties is purel y speculative until additional data is fo rth com ing. A lthough L. dol· lOnii may have some affinity to L. trigolll/s, the Fonner shares the presence of coriaceo us leaves, hairs spread unevenly on the adaxial leaf surfaces and an often obtuse leaf apex with L. colli· n1ls C. H. Wrigh t, wh ich also belongs to sect io n Fruticosi. However, L. daltonii differs from L collimrs in possessing recurved sepal apices and fl ower bud s arranged in two di stin ct rows. L collil/lls possesses loosely arranged fl ower bud s and appl a nate sepal apices. Furthermore, L daltonii fl owers mainly in Spri ng, while L. collinus fl owers chiefl y in Autu mn.
HEIGHT ABOVE SEA LEVEL
c:J Over 1500 m 32"S-+-\--,,!, ~~~~-~~~~~1--~~--i1~~~~t-----~~~~~~~~-~ 900.1500m
20
22"E
~.
Figure 8
KlHml1 distribution of L. daltonil .
23'
,.'
".
,.'
0
20
~o
".
EO 80
'OO ~m
"
S. An·. J. Bot. 1999,65(2)
148
Ecology and distribution L. da/tonii fl owe rs ma in ly from October to November. It is restricted in its distri bution, being found excl usive ly near Cape Infan ta (Figu re 8), preferring the loamy soils in the tra nsition
Afr . J. Bot. 62( I): 31 - 35. HES LOP-HARR ISON. Y. & S HIRVANNA, K.R. 1977. The recepti ve
s urface of the Angiospenll sl ig ma ..·II1II. Hut. 4 1: 1 233 - 1 25~. HILGER. H.H. 1985 . On logen ie. Morphulogil.! lilld systematischc
zone between Mountain Fy nbos (Rebelo 1996a) and South and
Bedeu tung gcflUgelter und gloclHltlictltragcndcr Cynoglossseae - und
South-west Coast Ren osterveld (Rebelo 1996b). Collections of L. dallonii have been few and far between, totalling four collectors with th e present revision. Th is could be indicative o f the rel-
Erilricheae-Frilchtc (Borag inaccac). BOI. JlIhl'b. SI'SI. IOS(3): 323-
ative remoteness of the locality . The precise number of
individuals is currently unknown, although the impression obtai ned during field work is that there are a sufficient number
378. JOEL D.M. 1983. AGS (Akian Green Sat'nlllin). a simpk difkrenlial
staining of platH material It)!' the light mil:roscope . Proc. RMS 18: 149- 151.
present, not withstanding the overall restricted distribution range.
REBELO, A.G . 1996a. Mountain Fynhos. In: Vegt.:tation of South
Additional field work is required to determine the precise co nservation status of the species.
Africa, Lesotho and Swaziland. (cds.) A.B. Low. & A.G. Rebelo.
Acknowledgements We thank the Foundati on for Researc h Development and the Univers ity o f Stellenbosch for fin ancial Sllpport. References DUY S. M.II. & VAN DER WA LT. J.J.A. 1')96. A ncw spL'c ics of I.ohosfelllon sect ion Gmndiflori (Boraginaceae) from South Ali·iea. S.
Dept. Environmental Affairs & Tourism. Pretoria. REBELO, AG . 1996h. South and SOllth-w~sl Coast Renosterve kl. In :
Vegetation o f South Africn.
L~so t ho
anti S\\'nzi lnnd. (ed::;.) A.R Lm\
& A.G. Rebelo. Dept. Environmcntal Afl ilirs & Tou rism. Pretoria. ROBARDS. A.W. 8: WII.SON. A.J. 11)1):;. Proced ures in EleCl ron
Microscopy. Wiler 8: Sons. N~\\' York. SE I BERT, J. 1978. Fruch tan;Jlmni sehe Ulllcl':->lIdlllllgcn all I.ilhospcrmeac (Boraginaccae) Di.IT BOl . .... : 1- 207 .