New South African soil fungi

Trans. Br. mycol. Soc. 52 (3),483-489 (1969) Printed in Great Britain

NEW SOUTH AFRICAN SOIL FUNGI By M. C. PAPENDORF Department of Botany, Uniuersity of Potchefstroom, Republic of South Africa (With Plate 35, and 3 Text-figures) This paper is a further contribution in the series describing the types of the various new genera and species of fungi isolated from the soil and litter of a mixed Acacia karroo community in the Transvaal. Veronaea simplex sp.nov., Exophiala brunneasp.nov, and Arthrocladium caudatum gen. et sp.nov, are described. Arthrocladium is characterized by a filamentous conidium consisting of an articulate spore-body and a septate, tail-like distal extension.

Arthrocladium gen.nov. Hyphae septatae, pallide fumoseque brunneae. Conidiophora obsoleta aut distincta, pallide infus cateque olivacea. Conidia singula in h yphis aut sola et terminaliter ca terv as p arvas in conidioph orib us fer entia, filamentosa proximalo articulatoque sporae corpore ac septata, gradatim decrescentc caudata distali extensione praedita, laevia, pallide infuscateque olivacea.

Hyphae septate, light smoky brown. Conidiophores obsolete or distinct, light brown-olivaceous. Conidia solitary on hyphae or single and in small groups terminally on conidiophores, filamentous with proximal articulate spore-body and septate, gradually tapering, tail-like distal extension, smooth, light brown-olivaceous. Type-species : Arthrocladium caudatum Papend. Arthrocladium caudatum sp.nov. (Text-fig. I; PI. 35, figs. 1-3) Coloniae in agaro tarde cr escentes, prostratae, hyphis veg etativis praecipue in medio immersis, saepe radiatim striatae; mycelium aerium atrogossypinum parce evolutum olivaceum ad fuscate brunneum, gradatim atratius transeuns, diam 2'5 cm quattuordecim diebus ad 25°C, parte reversa pallide brunneum, sed atratius adolescens. Hyphae pallide fumoseque brunneae, saepe septatae ad 4 pm diam. Conidiophora obsoleta aut distincta, continua aut septata, brevia et paxilli similia aut elongata et oblonga ad cylindrica, bruneola, ad 28 pm longitudine et 1'5-2"5 pm latitudine. Conidia sessilia et sola in hyphis aut singula parce gregaria terminaliter in conidiophoribus, aliquando ab cellulis inferioribus sporae corporis prolificantia, filamentosa, laevia, tenuitunicata, pallide infuscateque olivacea, 15-265 pm in longitudinem; 1-3 cellulae proximales conidiophorum corpus articulatum fingentes, 10-25 x 3-6 pm, cellula basalis plerumque paulo stipitata et hilo distincte truncato praedita ; extensio distalis caudataque multicellularis et paulatim attenuata 25-265 x 1-2'5 pm, 2-30 cellulas cylindricas 5-12'5 x 1-2'5 pm continens.

Colonies on potato carrot agar slow-growing, prostrate, with vegetative h yphae mainly immersed in the medium, often radially striate, sparse development of dark, cottony aerial mycelium, olivaceous to smoky brown

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becoming progressively darker, diameter 2'5 em in 14 days at 25°C, reverse ofcolony light brown but darker in age, Hyphae light smoky brown, frequently septate, up to 4 pm diam. Conidiophores obsolete or distinct, continuous or septate, short and peg-like or elongate and oblong to cylindrical, brownish, up to 28 pm long and 1.5-2'5 pm wide. Conidia

::C::rA

D B

Text-fig. I. Arthrocladium caudatum. A-C, lateral conidia showing stipitate and truncate base and septate basal cell; D, terminal conidium; E-H, conidiophores with single and grouped conidia. Note conidiophore growing from spore-body in F.

sessile and solitary on hyphae or single and in small groups terminally on conidiophore, occasionally proliferating from lower cells of the body of the spore, filamentous, smooth, thin-walled, light brown-olivaceous, 15265 pm long; 1-3 proximal cells form articulate body of conidium, 10-25 x 3-6 pm, basal cell usually slightly stipitate and with a distinct truncate hilum; distal portion caudiform, multicellular and gradually tapering to a narrow, rounded apex, 25-265 x 1-2'5 pm, consisting of 2-30 cylindrical cells, 5-12'5 x 1-2'5 pm.

New soil fungi. M. C. Papendorf Isolated from soil of Acaciakarroo community, Potchefstroom, Transvaal, Republic of S. Africa, Jan.-Feb. 1964, M. C. Papendorf. (M .C .P. 121). (PRE 43727, National Herbarium, Pretoria, Holotype.) Transfers of the holotype have been deposited in the Centraalbureau voor Schimmelcultures, Baarn, Netherlands, and in the Cryptogamic Herbarium, University of Potchefstroom.

J.. ,

,..•'

10p m

Text-fig.

2.

Veronaea simplex, conidiophores and conidia.

Arthrocladium caudatum is cultured successfully on various agar media including potato dextrose, potato carrot, malt, hay infusion and maize meal agar. Variations in colony characters are insignificant. The colonies are slow-growing at 25° but seem to develop more rapidly at higher temperatures, attaining an average diameter of 4'5 em in 14 days at 35 ° compared with 2'5 em at 25°. Sporulation is irregular and sporadic and normally a relatively limited crop of conidia is produced, mainly in older cultures. Potato carrot agar was found to be one of the more suitable sporulation media, but even on this, spore production was comparatively poor. The general sporulation

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pattern is fairly simple and uniform with the spores sessile on the hyphae or terminal on short, peg-like or more or less elongated but mostly poorly differentiated conidiophores (Text-fig. I). Usually the spores are borne singly but they may occur in small groups with each member attached directly to the tip of the conidiophore or with some originating individually or collectively from the lower body-cells of existing conidia or from secondary conidiophores growing from these cells (Text-fig. I). In rare instances conidia are produced in catenulate groups of not more than two cells. This condition probably arises through proliferation of the primary conidium. Veronaea simplex sp.nov, (Text-fig. 2.; PI. 35, figs. 4 and 5) Coloniae tarde crescentes, floccosae, brunneae. Hyphae leves, stramineae ad brunneolas, 1-2'5 pm diam. Conidiophora a latere in hyphis nascentia, simplicia vel ramosa incremento incerto, hila geniculata prominentiaque ostendentia, straminea vel fusee brunnea 2-60 x 1"5-2'5 pm. Conidia singula in conidiophori apice et ramis etsubinde ad sympodice invicemque formatos crescentesque apiculos, oblongata et elliptica ad breviter cylindrica, 6"5-1 I x 2"5-3"5 pm, hyalina ad obscure straminea, bicellularia, cellis saepe irregularibus et frequenter ad septum constrictis praedita, cella inferiore leniter attenuata ad hilum latum truncatum basilare.

Colonies on potato dextrose agar slow-growing, attaining a diameter of 2'5 em in 10 days at 25°, flocculent, brown. Hyphae smooth, strawcoloured to brownish, 1-2'5 pm diam. Conidiophores arising laterally on hyphae, simple or branched, of indeterminate growth and showing prominent geniculate scars, straw-coloured to light brown, 2-60 x I .52.5 pm. Conidia produced singly at the tip of the conidiophore and its branches and successively at the sympodially and alternately formed growing points, oblong-elliptical to short-cylindrical, 6'5-1 I x 2'5-3'5 pm, hyaline to faintly straw-coloured, z-celled with cells often unequal and frequently constricted at the septum, the lower cell slightly tapering to a broad truncate basal hilum. Isolated from leaf-litter and top soil of a mixed Acacia karroo community, Potchefstroom, Transvaal, Republic ofS. Africa, April 1966.J. W. du Toit, (M.C.P. 322). (PRE 43728, National Herbarium, Pretoria, Holotype.) Transfers of the holotype have been deposited in the Centraalbureau voor Schimmelcultures, Baarn, Netherlands, and in the Cryptogamic Herbarium, University of Potchefstroom. This fungus was originally identified as a new species of Sympodina, a genus erected by Subramanian & Lodha (1964) and based on S. coprophila Subr, & Lodha, which is similar to Pleurophragmium Cost. in the mode of development of the conidia, but differs from it in producing didymospores instead of phragmospores, and from Scolecobasidium in the absence ofdistinct denticles bearing the spores. They concluded that Sympodina appears to be congeneric with the Cladosporium sp. referred to and illustrated by Barron & Busch (1962, figs. 20-22). After consultation with Dr J. A. von Arx it was decided that Sympodina should be considered identical with Veronaea (Cifferi & Montemartini, 1958) and the latter name given nomenclatural priority. Veronaea simplex differs from V. botryosa and Sympodina coprophila mainly in the characters of the conidiophores and conidia. The conidiophores of

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the two latter species are up to 4oo/Lm and 350 /Lm long respectively and usually freely branched, while those of V. botryosa are inclined to be clavate terminally" In V. simplex the conidiophores are less elaborate and relatively short. The conidia of V. simplex, have a diameter of 2"5-3"5 /Lm against 3"2-4"8/Lm for S. coprophila. In contrast to V. simplex and S. coprophila the conidia of V. botryosa are up to 12 /Lm long, have pointed ends and show no constriction at the septum. Exophiala brunnea sp.nov. (Text-fig. 3; PI. 35, figs. 6, 7) Coloniae tarde crescentes in agaro farinae ad diam 1·5-2 em quattuordecim diebus ad 25°, mycelium aerium formantes murinum tholiforme 3-4 mm altum parte media, area peripherica depressa, fusee olivacea, reverta parte nigrovirens. Hyphae parce ramosae, partim funiculosae, glabrae, septatae, pallide olivaceae brunneaeque, 1-3 pm diam. Phialophora a latere in hyphis praeter sporifera aegre distinguenda a hyphis vegetatis etsi aliquando atratiora, crassitunicatiora, saepius septata, uni- vel multicellularia, simplicia vel ramosa, pallide brunnea, 8-350 pm longa; phialides terminaliter vel a latere in phialophoribus et ramis, vel a latere in hyphis natae, continuae vel in fundamento septatae, forma varia, ampullae simillimae, ovoideae, oblongatae, aequales vel curvatae, collo brevi neque prolongato, sporae formatione continua praedito, collari inconspicuo aliquandoque subtiliter fimbriato, 6-20 x 2-4 pm; hypharum cellae phialophororumque aliquando sporiferae a latere phialosporas formantes; phialosporae exogenae ennatae, singulae et ex ordine forma intumescentiarum ex phialidis ore, sporarum molem irregularem cohaerentem facientes non gemmando prolificantes, oblongatae vel aliquantum ovoideae, distaliter rotundatae a proxima parte attennatae et plerumque aliquantum stipitatae, continuae vel media parte I-septatae et aliquando paulo colligatae ad septum, lenes, pallide brunneae, 4.5-10 x 2-3 pm"

Colonies develop slowly on corn meal agar, reaching a diameter of 1"5-2 em in 14 days at 25°, forming a mouse-grey aerial mycelium, 3-4 mm high in centre, peripheral area depressed and dark olivaceous, reverse of colony greenish black. Hyphae sparingly branched, partly funiculose, smooth, septate, light olive-brown, 1-3 /Lm diam. Phialophores lateral on hyphae, apart from being sporiferous, not readily distinguishable from vegetative hyphae although sometimes darker, more thick-walled and more frequently septate, uni- or multicellular, simple or branched, light brown, 8-350 /Lm long; phialides borne terminally or laterally on phialophore and its branches, or laterally on hyphae, occasionally intercalary, continuous or basally septate, variable in shape, flask-shaped, ovoid, oblong, symmetrical or curved, neck short and not lengthening with continued spore-formation, collar inconspicuous and occasionally finely fimbriate, 6-20 x 2-4 /Lm, intercalary cells of hyphae and phialophores occasionally sporiferous, forming phialospores laterally; phialospores produced exogenously, singly and successively as swellings from mouth of phialide, forming irrregular coherent spore-masses, not proliferating by budding, oblong or somewhat ovoid, distally rounded, proximally tapered and usually slightly stipitate with a broad truncate hilum, continuous or medially I -septate and occasionally somewhat constricted at the septum, smooth, light brown, 4"5-10 x 2-3 psu. Isolated from top soil of an Acacia karroo community, Potchefstroom, Transvaal, Republic of S. Africa, April 1966.]. W. du Toit and M. C. Papendorf (M.C.P. 322). (PRE 43729, National Herbarium, Pretoria, Holotype.) Transfers of the holotype have been deposited in the Centraal-

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bureau voor Schimmelcultures, Baarn, Netherlands, and in the Cryptogamic Herbarium, University of Potchefstroom. Preliminary studies indicated that this organism resembles Phialophora in most of its characters excepting the 2-celled conidia. Because no fungus combining these features was known at the time Dr J. A. von Arx suggested

C».

A

~

A

()Y

20 p m

c

10 pm

Text-fig 3. Exophiala brunnea, A, phialides; B, phialophore, phialides and phialospores; C, phialides and phialospores. Note intercalary phialide.

that a new genus be erected to accomodate it, but before a detailed account could be prepared Carmichael (1966) published Exophiala salmonis, a new Phialophora-like fungus causing cerebral mycotoma of trout. When

Trans. Br. mycol. Soc.

Vol. 52.

Plate 35

(Facing

p. 489)

New soil fungi. M. C. Papendorf these organisms are compared it becomes clear that they are practically identical in their generic features though specifically quite distinct and ecologically completely unrelated. On agar media the growth habit and gross colony characters of these organisms agree very closely. Microscopically they differ as in that the phialide of E. salmonis often displays a distinct neck which, according to Carmichael (1966), becomes slightly longer as each spore is formed. This phenomenon, suggestive ofan annelophore, is entirely lacking in E. brunnea, In addition, the maximum lengths of the conidia of E. salmonis and E. brunnea are 16 and 10 /lm respectively, in E. brunnea the conidia are invariably r-septate while z-septate spores are found in E. salmonis. Chains of moniliform cells resembling blastospores characteristically present in E. salmonis are unknown in E. brunnea, and proliferation of the conidia by budding occurs only in E. salmonis. The author wishes to acknowledge the assistance received from Drs]. A. von Arx and G. L. Hennebert in the diagnosis of the various organisms. My sincere appreciation is due to Miss]. W. du Toit for preparing the text-figures and to Mr H. W. Simpson for making the Latin diagnosis. The South African C.S.I.R. and the Department ofAgricultural Technical Services are gratefully acknowledged for supporting this project financially. REFERENCES

BARRON, G. L. & BUSCH, L. V. (1962). Studies on the soil Hyphomycete Scolecobasidium. Can. ]. Bot. 40, 77-84. CARMICHAEL,J. W. (1966). Cerebral mycotoma of trout due to a Phialoplwra-like fungus. Sabouraudia 5, 120-123. CIFFERI, R. & MONTEMARTINI, A. (1958). Sui generi Muchmoria Sacco e Veronaea n.gen. (Dematiaceae, Didymosporae). Atti Ist. bot. Univ. Lab. crittogam. Pavia, Ser. 5, IS, 67-72, 1958, and in separate, pp. 1-6, 1957. SUBRAMANIAN, C. V. & LODHA, B. C. (1964). Four new coprophilous Hyphomycetes. Antonie van Leeuwenhoek 30, 3 I 7-330. EXPLANATION OF PLATE

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Figs. 1-3. Arthrocladium caudatum. Single and grouped conidia. Figs. 4, 5. Veronaea simplex. Conidial dusters, conidia and conidiophores showing geniculate scars. Oversized spore abnormal. Figs. 6, 7. Exophiala brunnea. Phialides and phialospores.

(Accepted for publication 23 September 1968)