Notes on myxomycetes

[ 647 ] Trans. Brit. mycol. Soc. 48 (4), 647-651 (1965) Printed in GreatBritain

NOTES ON MYXOMYCETES By B. ING Kindrogan Field Centre, Blairgowrie, Perthshire (With

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Text-figure)

The status of several taxa among the British myxomycetes is reviewed and two new combinations, Trichia contorta var. karstenii (Rost.) and Diacheopsis insessa (G. Lister), and a new name, Stemonitis microsperma are proposed. A key to the genus Echinostelium is provided and a new species, E. roseum is described.

While revising the nomenclature and distribution data for a Census Catalogue of British Myxomycetes a number of taxonomic problems inevitably occurred. Most of these are at the varietal level and examination oflarge series has shown that most of the varieties described in Lister ( I 925) are environmental variants with no constancy and connected by intermediates to the typical forms. Trichia contora (Ditm.) Rost. var. karstenii (Rost.) comb. nov.

Basionym: Hemiarcyria karstenii Rost., Monografia, Appendix 41, 1876 Synonym: Hemitrichia karstenii (Rost.) Lister, Mycetozoa, 178, 1894 Many varieties have been described in the Trichia contorta complex, some to be elevated subsequently to specific rank. The differences between them are slight, often based on one variable character. As only three infra specific variants of T. contorta are found in Britain the others, mainly Swiss, will not be considered until further material is available. The British varieties are T. contorta var. contorta, var. inconspicua (Rost.) Lister and Hemitrichia karstenii (Rost.) Lister. The first two were thought by Rostafinski to be distinct species but they are very similar in structure, var. inconspicua being a smaller, neater, ecologically distinct form found in piles of wet sticks; var. contorta is larger, with less regular elaters and usually darker, with more refuse in the peridium; it occurs on rotten wood. The forms with a branching network of elaters, with swellings at the branches, are usually, to quote Lister, 'so frequent that for convenience of reference they are placed in the genus Hemitrichia under the name H. karstenii Rost '. Many later authors follow this arrangement though mentioning the relationship. It is well known that many species of Trichia have abnormal Hemitrichia variants and Meylan (1925) even drew up a table of corresponding species in the two genera. Hemitrichia is not a satisfactory genus and to describe a variant which is probably abnormal in a different genus is confusing, though not unknown in the myxomycetes (vide Stemonitis and Comatricha). Apart from branching elaters and a tendency to form plasmodiocarps there is no character which separates H. karstenii from T. contorta. Its 4 1- 2

Transactions British Mycological Society frequent occurrence is the only excuse, as Lister said, for giving it specific rank in another genus. In order to confirm the relationship I propose that it should be regarded as a variety of T. contorta. It is not uncommon on dead bark and decorticated branches of deciduous trees. Diacheopsis insessa (G. Lister) comb.nov. Basionym: Lamproderma insessum G. Lister, Trans. Br. mycol. Soc. 4, 41, 19 12 The genus Lamproderma Rost. is full of problems and it is difficult to decide the limits ofa species, although the genus itselfis easily recognizable. Miss G. Lister (1912) described L. insessum from a lichen on a tree trunk in Morayshire and subsequently considered it a sessile form of L. echinulatum (Berk.) Rost. Sessile forms of Lamproderma have a columella, L. insessum has not. Meylan (1930) described a new genus Diacheopsis, differing from Lamproderma in lacking a columella. Dennison (1945) suggested that L. insessum might be included in Meylan's Diacheopsis but did not make the combination which I now propose. Apart from the type gathering this interesting species has only been found once, on a fruit-body of Fomes fomentarius Fr. on a standing birch trunk at Kindrogan, Perthshire, March 1964. More material is required for study and it seems likely that it will turn up in moist chamber culture of lichen-covered bark. Stemonitis microsperma nom.nov. Synonyms: Comatricha typhoides (Bull.) Rost. var. microspora Lister, Mycetozoa, 12 I, 1894 C. microspora G. Lister, Guide to British Mycetozoa, ed. 4, 39, 19 19 Stemonitis hyperopta Meylan var. microspora G. Lister, Mycetozoa, ed. 3, 134, 1925 This small species has had a chequered taxonomic history. It was first described as a variety of Comatricha typhoides (Bull.) Rost. by A. Lister in 1894. In 1919 G. Lister raised it to specific rank in Comatricha and in 1925 she transferred it to Stemonitis as a variety of Meylan's S. hvperopta. It is a distinct species as Miss Lister earlier thought and is distinguished from both C. typhoides and S. hyperopta by spore size, surface net of the capillitium and habitat. It lacks the partially persistent peridium of the former and also the silvery clothing of the stipe (' white silk stockings ') and has a complete, delicate surface net with fine, wavy threads. It is usually found on leaves of deciduous trees. Table I sets out the main characters for comparison. The complete surface net makes this a Stemonitis sp. but the resulting binomial is already occupied by S. microspora Lister (ex Morgan, 1894), which is a synonym of S. axifera (Bull.) Macbr. I therefore propose the epithet microsperma for this species. I have examined good material of this species in the British Museum

Myxomycetes. B. Ing Table C, typhoides

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S , hyperopia

H eight of spor an gia 2-5 m m ,

2'5-5 rnrn,

Stipe length

0'5-2 mm .

0' 1-0'5 mrn,

Stipe covering Per idiu m

Silvery film Silver y, often persistent Large colonies on wet rotten decidu ous wood Abundant Trace a t base of sporangiu m 6- 81'

Nil Fug aci ous

Us ua l habitat

Frequency Surface net Sp or e d iameter

Spo re markin gs

S, microsperma 1'7-3'2 mm , (average 2'4 of 54 samples) 0'5- 1'3 m m. (average 0·8 6 of 54 samples) Ni l Fu gacious

Small, loose clusters on Scattered or in sma ll conifero us wood and groups on dead deciduous lea ves bark Uncommon Rare t-i cover, irregular but Complete, del icate, uniform net dist inc t net 3'2-4'51' (average 3,8 of 200 spores of 54 spo rangia) Scattered lar ge warts Small warts or patches Complete , very fine of close reticulation reticul ation, faint bu t unev enly spa ced in well seen at X 1200 joined by faint bands gro ups ma gn ification of reticulation

c

10Jl

0

Fig , I , Echinostelium roseum. A, Typical globose sporangium ; B, extreme form of tur binate sporangium ; C, habit, showing sporangia on moss leafwith gemmae; D, spor e,

collections from the following localities: Lyme Regis, Dorset ; U plyme, Devon ; Wanstead Park, Essex; Witley, Surrey; Porlock, Somerset; Norfolk ; and from outside Eng land from Germany (Berlin area), Czechoslovakia (Chudenice) and the Netherlands (Doorwerth). I have not been able to trace the specimen supporting the record for Ohio, U.S .A., cited by Lister (1925), Martin (1949) and Hagelstein (1944).

Transactions British Mycological Society Echinostelium roseum sp.nov. (Fig. 1) Sporangia solitaria vel gregaria, ad 0'07 mm. alta, 32-3Sft diam., erecta, rosea, stipitata ; stipes brevis, erectus, pallidus, 31-3Sft altus; peridium transparens, pertinax; columella et capillitium absentes; sporae globosae, leves, roseae, 9'1-1O'3ft diam. Protoplasmodium roseum, ad 80ft diam. Typus IMI 112129, lectus a B. lng, 1 February 1965, Kindrogan Field Centre, Perthshire, Scotland. Habitat in museum, Orthotrichum lyellii Hook. et Tayl. in corticem aceris vivae.

Sporangia scattered or in small groups, total height 0'06-0'07 mm., globose to slightly turbinate, 32-35# diam., erect, bright pink, not fading; stipe broad at base, narrowing below sporangium, white, granular, 3135# long; peridium thin, transparent, persistent; columella and capillitium absent; spores few (20-24) globose, pale pink with distinct areoles, 9'1-10'3# diam. (average 9,8), dispersed as a mass which clings together. Protoplasmodium clear pink, up to 80# diam. This tiny species again lowers the size limit in the Myxomycetes. When Alexopoulos (1958) described E. elastichon he claimed it as the smallest slime mould known; E. roseum is about half the size. The new species differs from E. elastichon in its size, colour, which is very noticeable, the shorter, tapering stipe and much larger spores. It developed in moist chamber culture of bark of Acer pseudoplatanus L. covered with bryophytes, including Orthotrichum lyellii, O. affine Brid. and Radula complanata (L.) Dum. The bark was collected from living sycamores on I7 January 1965 and the first sporangia appeared on 29 January, clustered on the edges of the leaves of O. lyellii, distinct among the long brown gemmae of the moss. The protoplasmodium is bright clear pink and resembles in size that of Licea parasitica (Zukal) G. W. Martin with which it grows but is easily distinguished by its clear colour which does not darken. From the appearance of protoplasmodia on the moss to sporangium formation takes from twelve hours to five days. The type specimen consists of ten mature sporangia on a shoot of moss, further material is in the author's collection, No. 65013. As with E. elastichon this myxomycete is very difficult to mount. The same culture of bark also yielded: Licea teneraJahn, L. castanea G. Lister, L. parasitica (the rare stalked form as well as the usual sessile form), L. operculata (Wing.) G. W. Martin, Perichaena minor (G. Lister) Hagelst., Echinostelium minutum de Bary and Comatricha cornea G. Lister & Cran. The new species brings the number of known species of Echinostelium to five and makes necessary a slight emendation to the key given by Alexopoulos (1961). KEY TO THE SPECIES OF ECHINOSTELIUM

Capillitium absent roseum B. Ing Columella absent, spores 9-I0ft, pink Columella, if present, inconspicuous, spores 6'S-8ft, yellow elastichon Alexopoulos fragile Nann-Bremek, Columella well developed, spores 12-ISft, pink or grey Capillitium present minutum de Bary Capillitium scanty, spores 6-gft, white or pink Capillitium a well-developed globose net, spores 9-lOft, cream cribrarioides Alexopoulos

Myxomycetes. B.lng

651

My thanks are due to the authorities of the British Museum (Natural History) for permission to consult the collections and to Mr]. B. Evans for his kind help. REFERENCES

ALEXOPOULOS, C.]. (1958). Three new species of Myxomycetes from Greece. Mycologia, 5°,5 2-5 6. ALEXOPOULOS, C.]. (1961). A new species of Echinostelium from Greece. Amer. Midl. Nat. 66, 391-394. DENNISON, M. L. (1945). The genus Lamproderma and its relationships, I. Mycologia, 37, 80-108. HAGELSTEIN, R. (1944). Mycetozoa of North America. New York. LISTER, G. (1912). Mycetozoa of the Forres district. Trans. Br. mycol. Soc. 4, 38-44. LISTER, G. (1925). Monograph of the Mycetozoa, ed, 3. London. MARTIN, G. W. (1949). Myxomycetes. North American Flora, I. pt. I. New York. MEYLAN, C. (1925). Notes sur divers Myxomycetes du]ura et des Alpes. Bull. Soc. vaud. Sci. nat. 56, 65-74· MEYLAN, C. (1930). Note sur un nouveau genre de Myxomycetes. Bull. Soc. vaud. Sci. nat. 57, 147- 149. MORGAN, A. P. (1894). ]. Cincinn. Soc. nat. Hist. 16, 138.

(Accepted for publication 26 March 1965)