- Email: [email protected]
Botryoderma lateritium and B. Rostratum gen. et spp.nov. from soil in South Africa and Brazil
( 257 ] Trans. Br, mycol. Soc. 52 (2), 257-265 (1969)
Printed in Great Britain
BOTRYODERMA LATERITIUM AND B. ROSTRATUM GEN. ET SPP.NOV. FROM SOIL IN SOUTH AFRICA AND BRAZIL By M. C. PAPENDORF
Department of Botany, Unioersity of Potchefstroom, Republic of South Africa AND
H. P. UPADHYAY
Mycological Institute, Unioersity of Recife, Brazil (With Plate 17, and 2 Text-figures) A new genus, Botryoderma, is erected to accommodate two new species of soil hyphomycetes isolated in South Africa and Brazil respectively. The new genus and species, B. lateritium Papend. & Upadh, and B. rostratum Papend. & U padh., are described. The genus is characterized mainly by the thick-walled aleuriospores without germ slits or pores produced in small basipetal groups on inflated sporogenous cells.
In previous papers (Papendorf, 1967a, b; Papendorf & von Arx, 1966; Papendorf & du Toit, 1967; van der Aa, 1967) details of various new fungus types from the soil mycoflora of a mixed Acacia karroo community in the Transvaal have been presented. While studying an isolate thought to be of a new genus from this habitat, a subculture was sent to Professor G. L. Barron of the University of Guelph, Ontario, for his comments. At the time he was in possession of an isolate closely resembling Echinobotryum atrum Corda received from the second author of this paper. Having noticed the remarkable morphological similarity of the two organisms, Barron suggested a detailed comparative analysis of these fungi by both authors. Critical studies revealed that the two isolates represent two distinct species of a new genus of soil hyphomycetes. The nature of the cultures is such that it was found extremely difficult to make a complete and satisfactory analysis when using the more conventional mycological methods. Most of the problems encountered could be solved by means of the Riddel slide-culture technique (Riddel, 1950) and Nomarski interference-contrast microscopy. Botryoderma gen.nov. Fungus hyphomycetus, saprophyticus. Hyphae ramosae, septatae, leptodermae, hyalinae. Conidiophora variabilia, aliquando deficientia, praesentia autem uni- vel multicellularia, subglobosa vel brevius filamentosa, partim irregularia vel torulosa, tenuitunicata, hyalina. Cellulae sporogenae a latere in hyphis vel e latere terminaliter in conidiophoribus ennatae plerumque turgidae, subglobosae, obpyriformes, clavatae, subcylindricae, tenuitunicatae, hyalinae. Conidia aleuriosporae, denique sessiles vel in 1:7
Myc. 52
25 8
Transactions British Mycological Society
sterigmatibus brevibus, typice collectiveque parvis catervis successione basipetala in cellis sporogenis parte prima apicali, vel singulatim a latere in elementis hyphodeis vel conidiophoris cellis; singulatim sterigmatis ruptione disjuncta vel collective dividenda cella ferente, unicellulares, ellipticae, oblonge- ellipticae, ovoideae, globosae vel subglobosae, basilari vel sublaterali saepe leniter stipitato annulari secessionis hilo, laeves, hyalinae vel obscure coloratae, crassitunicatae sine germinis rima poroque.
Hyphae branched, septate, thin-walled, hyaline. Conidiophores variable, sometimes lacking, when present uni- or multicellular, subglobose to shortly filamentous and partly irregular or torulose, thin-walled, hyaline. Sporogenous cells produced laterally on fertile hyphae or laterally and terminally on conidiophores, usually inflated, subglobose, obpyriform, clavoid or subcylindrical, thin-walled, hyaline. Conidia aleuriospores, either sessile or on short sterigmata, produced typically and collectively in small groups in basipetal succession on the sporogenous cells with the first member apical, or singly and laterally on hyphal elements or cells of conidiophore, one-celled, elliptical, oblong-elliptical, ovoid, globose or subglobose, with a basal or sub lateral and often slightly stipitate annular secession scar, smooth, hyaline or faintly coloured, thick-walled, without germ slit or pore. Type-species: Botryoderma lateritium Papend. & U padh. Botryoderma lateritium sp.nov. (Text-fig. I; PI. 17, figs. 1-4) Coloniae in malti agaro appressae, praecipue immersae in medio, primo sine mycelio aerophilo, incolorae transeuntes ad pallidius fumosas, parte media exigue sublata, tegetem pulverulentulam, spongiosam, granulosam rhodolateritio colore fingentes, aliquando zonatae. Hyphae ramosae, tenuitunicatae, glabrae, septatae, hyalinae, I ' 5-4 pm diam; in fertili coloniae immaturae hyphae regione greges densas solide ramosis elementis fingentes; hyphae principales racemi et regio prima ramorum comparate pauca conidiophora et crebras laterales sporogenas cellas ferentes; hypharum ramorumque fines capillos comparate breves sterilesquefingentes, longitudine media 30-40 pm. Cellulae sporogenae, solae, plerumque turgidae, unicellulares, subglobosae ad obpyriformes, tenuitunicatae, hyalinae, fundamento septatae, 2'5-4pm diam, 1-4 conidia sterigmatibus brevissimus parientes vel sessilia, ordine basipetalo spora prima apicali, sterigmata o- 5- I' 5 pm diam, Conidia sporogena cellulis vel elementis hyphoideis educta, sola, unicellularia, late vel oblonge ellipsoidea, ovoidea vel sublgobosa, laevia, crassitunicata, hyalina ad obscure colorata, 4--8 x 4-6 pm; sporae disjunctae comparate angustum basilare vel sublaterale annulatumque hilum saepe minute membranaceo segmento praeditum ostendentes.
Colonies on malt agar appressed and mainly immersed in the medium, at first without aerial mycelium and colourless, becoming very light fumeus with the central region slightly raised forming a powdery spongiose, granulose mat with a rosy lateritius colour, occasionally zonate. Hyphae branched, thin-walled, smooth, septate, hyaline, 1'5-4 pm diam;in fertile region of young colony hyphae form dense clusters of compactly branched elements; main hyphal elements of clusters and proximal regions of their branches bear small numbers of short conidiophores and numerous lateral .sporogenous cells, ends of hyphae and branches form relatively short sterile filaments radiating from the mature fertile clusters, average length 30-40 pm. Sporogenous cells single, usually inflated, one-celled, subglobose to obpyriform, thin-walled, hyaline, basally septate, 2'5-4 pm diam, producing 1-4 conidia on very short sterigmata, or sessile, in basi-
New soilfungi. M. C. Papendorf and H. P. Upadhyay
259
petal sequence and with the first spore apical, sterigmata 0·5-1·S j.tm diam. Conidia produced on sporogenous cells or hyphal elements, single, onecelled, broadly to oblong-elliptical, ovoid or subglobose, smooth, thickwalled, hyaline to faintly coloured, 4-8 x 4-6 usi»; detached spores show a
10p m
Text-fig.
J.
Botryoderma lateritium . Hyphae, conidiophores, sporogenous cells and conidi a .
narrow basal or sublateral annular secession scar often ornamented with a minute membranaceous frill representing the remains of the ruptured sterigma or sporogenous cell. Isolated from top soil of mixed Acacia karroo community, Potchefstroom, Transvaal, Republic of S. Africa, Jan.-Feb. 1964, M. C. Papendorf (M.C.P. 7). (PRE 44223, 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. Botryoderma lateritium is cultured successfully on a variety of agar media including potato dextrose (PDA), potato carrot (PCA), corn meal (CMA) and malt (MA) and the resulting colonies display only minor variations in 17-2
260
Transactions British Mycological Society
growth-rate, colour and fertility. Their growth is moderately slow at 25 DC, reaching a diameter of 2-3'5 cm within 14 days. The young mycelial mat is extremely delicate in all cases. On PCA it is pellucid and glassy but inclined to become more white on PDA and buffon MA. In slightly older cultures the colour tends to change to a light biscuit in the case of PDA and a light rosy rust on MA. Sporulation commences near the centre and the fertility of the colonies ranges from high on malt to moderate on PDA and low on both PCA and CMA. The colour of the mature fertile sporogenous area is basically a light terra-cotta though inclined to be more rusty-brown on PCA and CMA while it has a distinct rosy hue on PDA and MA. As the colonies age the colour remains more or less unchanged except on MA, where it eventually becomes a dull brown. The reverse of the young sporulating colonies varies from a very light rosy buff (PCA, PDA and CMA) to a darker brown or even orange-brown on MA. The vegetative stage is inclined to develop largely below the surface of the agar with only a very slight development of a cottony aerial mycelium. In the central region a delicate superficial mycelial mat is produced at a comparatively early stage and on this spores make their appearance within a few days. Prior to spore formation this superficial covering forms localized aggregates of compactly branched hyphae with the branches more or less opposite and gradually tapering to spine-like structures (PI. 17, figs, I, 2). In older cultures these structures become unevenly thickened and radiate freely from the fertile clusters. They are up to 70 !tm long with an average length of 30-40 tuu. The main hyphae and the proximal regions of their branches are sporiferous and bear groups of 1-4 spores on relatively small subglobose or obpyriform sporogenous cells developing laterally on the fertile hyphae, or less frequently on short conidiophores or directly on the hyphal elements (Text-fig. I; PI. 17, figs. 2, 3). Detachment of the conidia is effected individually by rupture of the sterigma or sporogenous cell or collectively by liberation of the bearer cell. This species is distinguished by the relatively slow growth of the colonies, the lateritius colour of the fertile colonies, the small number of distinct and well developed conidiophores, most of the sporogenous cells being borne directly on the hyphal elements, the broadly elliptical spores without an apical beak, and the relatively short, setaceous hyphal ends radiating from the fertile clusters. Botryoderma rostratum sp.nov, (Text-fig. 2; PI. 17, figs. 5-10) Coloniae in malti agaro confertim appressae, hyphis vegetatis magnopere medio immersis, primo incolorae, in regione media roseae transeuntes; coloniae veteriores sublevatae, tegetem solutam, sordidam, granulatam, spongiosam zona pallide peripherica interdum distincte zonatam ostendentes. Hyphae parce ramosae, tenuitunicatae, laevae, septatae, hyalinae, 1-4 pm diam; regione fertili racemis densos libere ramosis elementis proxima parte structuras generantes ferentibus, extrema parte fere gracilis, denique crassitunicatas, setaceas vel spiriformes structuras copiose radiantes e racemis maturis porrectae, longitudine media 70-80 psx». Conidiophora variabilia, aggregata, unicellularia vel multicellularia, simplicia vel ramosa, subglobosa ad breviter filamentosa saepe inaequalia vel torulosa, tenuitunicata, hyalina, 4-40 x 2-4 pm, saepe apicaliter
New soilfungi. M. C. Papendorf and H. P. Upadhyay
26r
crescentia cellulas sequentes laterales sporogenas successione acropetala fingentia, post separationem conidium cellarumque sporogenarum, saepe dentiformibus hills abscisionis aspere notata. Cellulae sporogenae a latere in hyphis vel a latere terminaliterque in conidiophoribus, plerumque turgidae, subglobosae, obpyriformes, c1avatae vel subcylindricae aut cylindricae, 3-20 x 2·5-4 /lm, fundamento septatae, tenuitunicatae, hyalinae, saepe subtiliter denticulatae post sporarum separationem, deciduae et saepe sporis haerentes evanescentes. Conidia singula in cellulis hypharum conidiophoribusque innata vel insignius parvis basipetalis catervis (1-4) in cellis sporogenis, sessilia vel in
10 l' m
Text-fig.
2.
Botryoderma rostratum. Hyphae, conidiophores, sporogenous cells and conidia.
subtilibus comparate brevibus sterigmatibus, unicellularia, elliptica, late fusiformelliptica, ovoidea vel sublgobosa saepe apicali spinosa rostro ad 4·5 /lm longitudine, 5·5-9 x 5-6/lID (sine spina), hyalina vel obscure coloratae, laeva, crassitunicata, angusto annulari hilo basilari vel sublaterali 0.5-1 /lm diam, saepe residuis sterigmatis vel cella sporogena segmentum delicatum sequens membranaceum fingentes praedita.
262
Transactions British Mycological Society
Colonies on malt agar closely appressed, with vegetative hyphae largely immersed in the medium, initially colourless, becoming rosaceous in fertile region, older colonies slightly raised forming a loose, dull, granularly spongiose mat with a light peripheral zone, sometimes distinctly zonate. Hyphae sparsely branched, thin-walled, smooth, septate, hyaline, 1-4 flm diam; hyphae offertile region forming dense aggregates offreely branched elements which bear reproductive structures proximally and are distally extended to slender, eventually thick-walled, setaceous or spiniform structures radiating freely from the mature clusters, average length 70-80 flm. Conidiophores variable, aggregated, uni- or multicellular, simple or branched, subglobose to shortly filiform, often irregular or torulose, thin-walled, hyaline, 4-40 x 2-4 flm, often extending apically and forming successive lateral sporogenous cells in acropetal succession, after secession of conidia and sporogenous cells often roughly marked with dentiform abscission scars. Sporogenous cells produced laterally on hyphae or laterally and terminally on conidiophores, usually inflated, subglobose, obpyriform, clavoid or subcylindrical to cylindrical, 3-20 x 2"5-4 usu, basally septate, thin-walled, hyaline, rarely minutely denticulate after secession of spores, deciduous and frequently remaining attached to the spores, evanescent. Conidia produced singly on cells of hyphae and conidiophores or more typically in small basipetal groups (1-4) on the sporogenous cells, sessile or on delicate, relatively short sterigmata, one-celled, broadly fusiform-elliptical, ovoid or subglobose, often with an apical spine-like beak up to 4·5 flm long, 5"5-9 x 4-6 flm (without beak), hyaline or faintly coloured, smooth, thick-walled; annular abscission scar basal or sublateral, frequently with remains of sterigma or sporogenous cell forming a delicate, trailing membranaceous frill. Isolated from sandy paddy soil at 5-IO em depth in the State of Maranhao, Brazil. Cultures of the type have been deposited in the Mycotheca, University of Recife, Brazil; the Centraalbureau voor Schimmelcultures, Baarn, Netherlands, and the Cryptogamic Herbarium, University of Potchefstroom. Botryoderma rostratum grows well on various agar media such as PDA, PCA, CMA and MA. In all cases the more salient features of the colonies remain remarkably constant and uniform. The growth is moderately fast and spreading, reaching a diameter of 6.5-7 em in 14 days at 25°. On PDA the colonies are more restricted and compact" The young mycelial growth is delicately cottony and without colour in the dark but soon becomes rosaceous to rosy lilac when exposed to daylight and as sporulation commences. In age the colonies lose their original colour, eventually becoming a drab olive-brown. The vegetative mycelium is mainly immersed in the medium with only a sparse development of aerial mycelium. Fertile sporogenous areas are localized, resulting in a granular distribution of the fertile clusters in the mature colonies. In each fertile area sporulation is preceded by active branching of the hyphae followed by the appearance of numerous locally aggregated conidiophores and sporogenous cells. From each of these fertile clusters, sterile, setaceous and somewhat echinate hyphal ends radiate
New soil fungi. M. C. Papendorf and H. P. Upadhyay
263
freely (PI. 17, fig. 6). These structures are up to 200 pm long with an average length of 70-80 pm, become thick-walled in older cultures and are inclined to disintegrate when handled. The superficial spongy mat characteristic of the mature colony consists of dense assemblages of loosely arranged spore-bearing clusters. In older cultures this mat is sometimes completely covered by a darker hyphal growth obscuring its granular nature. Conidiophores and unicellular sporogenous cells are formed indiscriminately over the entire surface of the hyphae and hyphal branches excepting the extreme threadlike ends radiating freely from the fertile clusters (PI. 17, figs. 7,8). The sporogenous cells bear 1-4 conidia in basipetal succession (PI. 17, fig. 5) with the first spore normally initiated apically or subapically. When the first spore is formed subapically and the lateral spores sublaterally towards the apex it results in an apical group in which the sequence is not readily recognizable. Conidiophores may consist of more than one cell and are then cylindrical, torulose or somewhat irregular in shape. In most cases a multicellular conidiophore terminates in a sporogenous cell bearing the usual group of spores in basipetal succession while the subapical cells also produce conidia either singly and directly on the cells or in basipetal groups on laterally formed sporogenous cells. Where the conidiophores are fairly extensive the bearer cells are initiated in acropetal succession on the conidiophore with the entire structure ultimately forming a dense botryose cluster of sporogenous cells and conidia (PI. 17, figs. 7, 8). Large numbersof these spore-bearing elements are produced in close proximity in the dense fertile clusters typical of this genus. The conidia do not secede readily and usually do so individually by rupture of the sterigma or sporogenous cell, or in groups by separation of the bearer cell. Regarding the apparent thickness of the cell wall of the conidia it should be pointed out, as was done in the case of Melanophoma (Papendorf & du Toit, 1967) that this feature could be attributed to an illusion caused by a partial retraction of the cell contents from the inner surface of the wall. Crushed conidia with partly extruded plasm appear to have cell walls of normal thickness (PI. 17, fig. 10). This species is characterized mainly by the relatively rapid growth and rosaceous or rosy lilac colour of the colonies, the abundant, well differentiated conidiophores and broadly fusiform-ellipsoid, distally rostrate conidia, and the relatively long setaceous or spiniform hyphal ends radiating from "the spore bearing clusters. Botryoderma seems to be most nearly related to genera like Gilmaniella (Barron, 1964), and Ward!Jmyces and Asteromyces as described by Brooks & Hansford (1922) and MoreauSe Moreau (1941) respectively and further emended and validated by Hennebert (1962). Though differing in important features, these genera agree basically in producing their conidia more or less similarly in basipetal succession on a swollen sporogenous cell. In Wardomyces the sporogenous cell is swollen before sporulation commences, while Asteromyces is characterized by the swelling of the sporogenous cells as a result of successive development of conidia. According to Hennebert this fact influences and determines the position of these two genera in the present systems of classification as proposed by Hughes (1953) and
264
Transactions British Mycological Society
Tubaki (1958) causing their separation in different groups which have not yet been satisfactorily delimited. In a paper on Gilmaniella (Barron, 1964) and also in a personal communication in which reference is made to views expounded in his book, Professor Barron (1968) points out that he regards the spores of genera like Gilmaniella, Wardomyces, Echinobotryum and Asteromyces as aleuriospores in view of the fact that in all these forms the spore production is basically of the aleuriospore type and that the spores are released by rupture of the sporogenous cell. A separation of the forms producing solitary or botryose aleuriospores (Aleuriosporae) from those forming their conidia in basipetal chains from an annelated sporogenous cell (Annelophorae) is proposed. This would mean that the above-mentioned and similar genera should be included in Hughes's (1953) Section III of the Aleuriosporae. Since this applies equally well to Botryoderma it seems justified to place this genus in the same section. Regarding the sporogenous cell and the mode of spore production, Botryoderma shows a closer relationship to Gilmaniella and Wardomyces than to Asteromyces, In Botryoderma the size of the spore-bearing cell remains constant while producing only a limited number of spores in a basipetal succession which does not result in successive cruciate whorls of conidia as in Asteromyces. The attachment of the spores agrees more or less with that which is found in Gilmaniella and Wardomyces and more especially in W. hughesii, where each conidium is borne on a short denticle. In Botryoderma the conidia are generally more or less sessile or shortly stalked while the long denticles characteristic of Asteromyces are never present. In spore characters Botryoderma shows relationship to Gilmaniella, Wardomyces and Asteromyces. The spores agree with those of Wardomyces in being thick-walled and with those of Asteromyces in the absence of a germ slit or pore characteristically present in Wardomyces and Gilmaniella. In addition, Botryoderma has hyaline or only faintly coloured hyphae and conidiophores (sporogenous cells) like those of Wardomyces. From a comparison of these genera it is evident that Botryoderma shares features with Wardomyces, Asteromyces, Gilmaniella, Echinobotryum and others but at the same time differs so significantly that it is impossible to consider it congeneric with any. We feel greatly indebted to Professor G. L. Barron for his interest in this work, his valuable comments relating to the diagnoses and manuscript and for combining us in this undertaking; to Dr G. L. Hennebert for his kind advice and for proposing the name; to Dr J. A. von Arx for his generous support and encouragement; to Miss J. W. du Toit for making the drawings and photomicrographs, and to Mr H. W. Simpson for preparing the Latin diagnoses. The senior author wishes to acknowledge financial support from the South African C.S.I.R. and the Department of Agricultural Technical Services, Pretoria.
Trans. Br. mycol. Soc.
Vol. 52.
Plate 17
(Facing p. 265)
New soilfungi. M. C. Papendorf and H. P. Upadhyay
265
REFERENCES
BARRON, G. L. (1964). A new genus of the Hyphomycetes from soil. Mycologia 56, 5 14-518. BARRON, G. L. (1968). The genera of hyphomycetes from soil, xiii+364 pp. Baltimore: Williams and Wilkins. BROOKS, F. T. & HANSFORD, B. A. (1922). Mould growth upon cold-store meat. Trans. Br. mycol. Soc. 8, 113-142. HENNEBERT, G. L. (1962). Wardomyces and Asteromyces. Can. ]. Bot. 40, 12°3-1216. HUGHEs, S.J. (1953). Conidiophores, conidia and classification. Can.]. Bot. 31:,577-659. MOREAU, F. & MOREAU, F. (1941). Premiere contribution it l'etude de la microflore des dunes. Revue Mycol. N.S. 6, 49-g4. PAPENDORF, M. C. (1967a). Two new genera of soil fungi from South Africa. Trans. Br, mycol. Soc. 50, 69-75. PAPENDORF, M. C. (1967b). Leptodiscus afriaanus sp.nov, Trans. Br, mycol. Soc. 50, 687-69°. PAPENDORF, M. C. & DUTOIT,J. W. (1967). Melanophoma, anewgenusoftheSphaeropsidales. Trans. Br, mycol, Soc. 50, 503-506. PAPENDORF, M. C. & VON ARx, J. A. (1966). Herpotrichia striatispora, a new Ascomycete from South Africa. Nova Hedwiga 1:3, 395-397. RIDDEL, R. W. (1950). Permanent stained mycological preparations obtained by slide culture. Mycologia 42, 265-27°. TUBAKI, K. (1958). Studies of the Japanese Hyphomycetes. V. ]. Hattori bot. Lab. 20, 142 - 2 44. VAN DER AA, H. A. (1967). A new species ofCurvularia. Persoonia 5, 45-46. EXPLANATION OF PLATE
17
Figs. 1-4. Botryoderma lateritium. Figs. 5-10. B. rostratum. Fig. I. Young mycelium forming fertile clusters on agar plate. Fig. 2. Cluster showing sporogenous cells, apical conidia and spine-like hyphal ends. Fig. 3. Various basipetal groups of conidia on sporogenous cells. Fig. 4. Conidia. Fig. 5. Central area offig. 7 enlarged to show hyphae, conidiophores, sporogenous cells and young conidia. Note basipetal spore initiation. Fig. 6. Mature setose spore-bearing cluster. Figs. 7, 8. Conidiophores, sporogenous cells and young conidia. Note acropetal initiation of successive sporogenous cells on conidiophore (fig. 7, centre; fig. 8, left) and basipetal group of conidia (fig. 8, right). Fig. g. Intact conidia. Fig. 10. Crushed conidia showing effect on the apparent thickening of the wall.
(Accepted for publication
10
July 1968)
Printed in Great Britain
BOTRYODERMA LATERITIUM AND B. ROSTRATUM GEN. ET SPP.NOV. FROM SOIL IN SOUTH AFRICA AND BRAZIL By M. C. PAPENDORF
Department of Botany, Unioersity of Potchefstroom, Republic of South Africa AND
H. P. UPADHYAY
Mycological Institute, Unioersity of Recife, Brazil (With Plate 17, and 2 Text-figures) A new genus, Botryoderma, is erected to accommodate two new species of soil hyphomycetes isolated in South Africa and Brazil respectively. The new genus and species, B. lateritium Papend. & Upadh, and B. rostratum Papend. & U padh., are described. The genus is characterized mainly by the thick-walled aleuriospores without germ slits or pores produced in small basipetal groups on inflated sporogenous cells.
In previous papers (Papendorf, 1967a, b; Papendorf & von Arx, 1966; Papendorf & du Toit, 1967; van der Aa, 1967) details of various new fungus types from the soil mycoflora of a mixed Acacia karroo community in the Transvaal have been presented. While studying an isolate thought to be of a new genus from this habitat, a subculture was sent to Professor G. L. Barron of the University of Guelph, Ontario, for his comments. At the time he was in possession of an isolate closely resembling Echinobotryum atrum Corda received from the second author of this paper. Having noticed the remarkable morphological similarity of the two organisms, Barron suggested a detailed comparative analysis of these fungi by both authors. Critical studies revealed that the two isolates represent two distinct species of a new genus of soil hyphomycetes. The nature of the cultures is such that it was found extremely difficult to make a complete and satisfactory analysis when using the more conventional mycological methods. Most of the problems encountered could be solved by means of the Riddel slide-culture technique (Riddel, 1950) and Nomarski interference-contrast microscopy. Botryoderma gen.nov. Fungus hyphomycetus, saprophyticus. Hyphae ramosae, septatae, leptodermae, hyalinae. Conidiophora variabilia, aliquando deficientia, praesentia autem uni- vel multicellularia, subglobosa vel brevius filamentosa, partim irregularia vel torulosa, tenuitunicata, hyalina. Cellulae sporogenae a latere in hyphis vel e latere terminaliter in conidiophoribus ennatae plerumque turgidae, subglobosae, obpyriformes, clavatae, subcylindricae, tenuitunicatae, hyalinae. Conidia aleuriosporae, denique sessiles vel in 1:7
Myc. 52
25 8
Transactions British Mycological Society
sterigmatibus brevibus, typice collectiveque parvis catervis successione basipetala in cellis sporogenis parte prima apicali, vel singulatim a latere in elementis hyphodeis vel conidiophoris cellis; singulatim sterigmatis ruptione disjuncta vel collective dividenda cella ferente, unicellulares, ellipticae, oblonge- ellipticae, ovoideae, globosae vel subglobosae, basilari vel sublaterali saepe leniter stipitato annulari secessionis hilo, laeves, hyalinae vel obscure coloratae, crassitunicatae sine germinis rima poroque.
Hyphae branched, septate, thin-walled, hyaline. Conidiophores variable, sometimes lacking, when present uni- or multicellular, subglobose to shortly filamentous and partly irregular or torulose, thin-walled, hyaline. Sporogenous cells produced laterally on fertile hyphae or laterally and terminally on conidiophores, usually inflated, subglobose, obpyriform, clavoid or subcylindrical, thin-walled, hyaline. Conidia aleuriospores, either sessile or on short sterigmata, produced typically and collectively in small groups in basipetal succession on the sporogenous cells with the first member apical, or singly and laterally on hyphal elements or cells of conidiophore, one-celled, elliptical, oblong-elliptical, ovoid, globose or subglobose, with a basal or sub lateral and often slightly stipitate annular secession scar, smooth, hyaline or faintly coloured, thick-walled, without germ slit or pore. Type-species: Botryoderma lateritium Papend. & U padh. Botryoderma lateritium sp.nov. (Text-fig. I; PI. 17, figs. 1-4) Coloniae in malti agaro appressae, praecipue immersae in medio, primo sine mycelio aerophilo, incolorae transeuntes ad pallidius fumosas, parte media exigue sublata, tegetem pulverulentulam, spongiosam, granulosam rhodolateritio colore fingentes, aliquando zonatae. Hyphae ramosae, tenuitunicatae, glabrae, septatae, hyalinae, I ' 5-4 pm diam; in fertili coloniae immaturae hyphae regione greges densas solide ramosis elementis fingentes; hyphae principales racemi et regio prima ramorum comparate pauca conidiophora et crebras laterales sporogenas cellas ferentes; hypharum ramorumque fines capillos comparate breves sterilesquefingentes, longitudine media 30-40 pm. Cellulae sporogenae, solae, plerumque turgidae, unicellulares, subglobosae ad obpyriformes, tenuitunicatae, hyalinae, fundamento septatae, 2'5-4pm diam, 1-4 conidia sterigmatibus brevissimus parientes vel sessilia, ordine basipetalo spora prima apicali, sterigmata o- 5- I' 5 pm diam, Conidia sporogena cellulis vel elementis hyphoideis educta, sola, unicellularia, late vel oblonge ellipsoidea, ovoidea vel sublgobosa, laevia, crassitunicata, hyalina ad obscure colorata, 4--8 x 4-6 pm; sporae disjunctae comparate angustum basilare vel sublaterale annulatumque hilum saepe minute membranaceo segmento praeditum ostendentes.
Colonies on malt agar appressed and mainly immersed in the medium, at first without aerial mycelium and colourless, becoming very light fumeus with the central region slightly raised forming a powdery spongiose, granulose mat with a rosy lateritius colour, occasionally zonate. Hyphae branched, thin-walled, smooth, septate, hyaline, 1'5-4 pm diam;in fertile region of young colony hyphae form dense clusters of compactly branched elements; main hyphal elements of clusters and proximal regions of their branches bear small numbers of short conidiophores and numerous lateral .sporogenous cells, ends of hyphae and branches form relatively short sterile filaments radiating from the mature fertile clusters, average length 30-40 pm. Sporogenous cells single, usually inflated, one-celled, subglobose to obpyriform, thin-walled, hyaline, basally septate, 2'5-4 pm diam, producing 1-4 conidia on very short sterigmata, or sessile, in basi-
New soilfungi. M. C. Papendorf and H. P. Upadhyay
259
petal sequence and with the first spore apical, sterigmata 0·5-1·S j.tm diam. Conidia produced on sporogenous cells or hyphal elements, single, onecelled, broadly to oblong-elliptical, ovoid or subglobose, smooth, thickwalled, hyaline to faintly coloured, 4-8 x 4-6 usi»; detached spores show a
10p m
Text-fig.
J.
Botryoderma lateritium . Hyphae, conidiophores, sporogenous cells and conidi a .
narrow basal or sublateral annular secession scar often ornamented with a minute membranaceous frill representing the remains of the ruptured sterigma or sporogenous cell. Isolated from top soil of mixed Acacia karroo community, Potchefstroom, Transvaal, Republic of S. Africa, Jan.-Feb. 1964, M. C. Papendorf (M.C.P. 7). (PRE 44223, 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. Botryoderma lateritium is cultured successfully on a variety of agar media including potato dextrose (PDA), potato carrot (PCA), corn meal (CMA) and malt (MA) and the resulting colonies display only minor variations in 17-2
260
Transactions British Mycological Society
growth-rate, colour and fertility. Their growth is moderately slow at 25 DC, reaching a diameter of 2-3'5 cm within 14 days. The young mycelial mat is extremely delicate in all cases. On PCA it is pellucid and glassy but inclined to become more white on PDA and buffon MA. In slightly older cultures the colour tends to change to a light biscuit in the case of PDA and a light rosy rust on MA. Sporulation commences near the centre and the fertility of the colonies ranges from high on malt to moderate on PDA and low on both PCA and CMA. The colour of the mature fertile sporogenous area is basically a light terra-cotta though inclined to be more rusty-brown on PCA and CMA while it has a distinct rosy hue on PDA and MA. As the colonies age the colour remains more or less unchanged except on MA, where it eventually becomes a dull brown. The reverse of the young sporulating colonies varies from a very light rosy buff (PCA, PDA and CMA) to a darker brown or even orange-brown on MA. The vegetative stage is inclined to develop largely below the surface of the agar with only a very slight development of a cottony aerial mycelium. In the central region a delicate superficial mycelial mat is produced at a comparatively early stage and on this spores make their appearance within a few days. Prior to spore formation this superficial covering forms localized aggregates of compactly branched hyphae with the branches more or less opposite and gradually tapering to spine-like structures (PI. 17, figs, I, 2). In older cultures these structures become unevenly thickened and radiate freely from the fertile clusters. They are up to 70 !tm long with an average length of 30-40 tuu. The main hyphae and the proximal regions of their branches are sporiferous and bear groups of 1-4 spores on relatively small subglobose or obpyriform sporogenous cells developing laterally on the fertile hyphae, or less frequently on short conidiophores or directly on the hyphal elements (Text-fig. I; PI. 17, figs. 2, 3). Detachment of the conidia is effected individually by rupture of the sterigma or sporogenous cell or collectively by liberation of the bearer cell. This species is distinguished by the relatively slow growth of the colonies, the lateritius colour of the fertile colonies, the small number of distinct and well developed conidiophores, most of the sporogenous cells being borne directly on the hyphal elements, the broadly elliptical spores without an apical beak, and the relatively short, setaceous hyphal ends radiating from the fertile clusters. Botryoderma rostratum sp.nov, (Text-fig. 2; PI. 17, figs. 5-10) Coloniae in malti agaro confertim appressae, hyphis vegetatis magnopere medio immersis, primo incolorae, in regione media roseae transeuntes; coloniae veteriores sublevatae, tegetem solutam, sordidam, granulatam, spongiosam zona pallide peripherica interdum distincte zonatam ostendentes. Hyphae parce ramosae, tenuitunicatae, laevae, septatae, hyalinae, 1-4 pm diam; regione fertili racemis densos libere ramosis elementis proxima parte structuras generantes ferentibus, extrema parte fere gracilis, denique crassitunicatas, setaceas vel spiriformes structuras copiose radiantes e racemis maturis porrectae, longitudine media 70-80 psx». Conidiophora variabilia, aggregata, unicellularia vel multicellularia, simplicia vel ramosa, subglobosa ad breviter filamentosa saepe inaequalia vel torulosa, tenuitunicata, hyalina, 4-40 x 2-4 pm, saepe apicaliter
New soilfungi. M. C. Papendorf and H. P. Upadhyay
26r
crescentia cellulas sequentes laterales sporogenas successione acropetala fingentia, post separationem conidium cellarumque sporogenarum, saepe dentiformibus hills abscisionis aspere notata. Cellulae sporogenae a latere in hyphis vel a latere terminaliterque in conidiophoribus, plerumque turgidae, subglobosae, obpyriformes, c1avatae vel subcylindricae aut cylindricae, 3-20 x 2·5-4 /lm, fundamento septatae, tenuitunicatae, hyalinae, saepe subtiliter denticulatae post sporarum separationem, deciduae et saepe sporis haerentes evanescentes. Conidia singula in cellulis hypharum conidiophoribusque innata vel insignius parvis basipetalis catervis (1-4) in cellis sporogenis, sessilia vel in
10 l' m
Text-fig.
2.
Botryoderma rostratum. Hyphae, conidiophores, sporogenous cells and conidia.
subtilibus comparate brevibus sterigmatibus, unicellularia, elliptica, late fusiformelliptica, ovoidea vel sublgobosa saepe apicali spinosa rostro ad 4·5 /lm longitudine, 5·5-9 x 5-6/lID (sine spina), hyalina vel obscure coloratae, laeva, crassitunicata, angusto annulari hilo basilari vel sublaterali 0.5-1 /lm diam, saepe residuis sterigmatis vel cella sporogena segmentum delicatum sequens membranaceum fingentes praedita.
262
Transactions British Mycological Society
Colonies on malt agar closely appressed, with vegetative hyphae largely immersed in the medium, initially colourless, becoming rosaceous in fertile region, older colonies slightly raised forming a loose, dull, granularly spongiose mat with a light peripheral zone, sometimes distinctly zonate. Hyphae sparsely branched, thin-walled, smooth, septate, hyaline, 1-4 flm diam; hyphae offertile region forming dense aggregates offreely branched elements which bear reproductive structures proximally and are distally extended to slender, eventually thick-walled, setaceous or spiniform structures radiating freely from the mature clusters, average length 70-80 flm. Conidiophores variable, aggregated, uni- or multicellular, simple or branched, subglobose to shortly filiform, often irregular or torulose, thin-walled, hyaline, 4-40 x 2-4 flm, often extending apically and forming successive lateral sporogenous cells in acropetal succession, after secession of conidia and sporogenous cells often roughly marked with dentiform abscission scars. Sporogenous cells produced laterally on hyphae or laterally and terminally on conidiophores, usually inflated, subglobose, obpyriform, clavoid or subcylindrical to cylindrical, 3-20 x 2"5-4 usu, basally septate, thin-walled, hyaline, rarely minutely denticulate after secession of spores, deciduous and frequently remaining attached to the spores, evanescent. Conidia produced singly on cells of hyphae and conidiophores or more typically in small basipetal groups (1-4) on the sporogenous cells, sessile or on delicate, relatively short sterigmata, one-celled, broadly fusiform-elliptical, ovoid or subglobose, often with an apical spine-like beak up to 4·5 flm long, 5"5-9 x 4-6 flm (without beak), hyaline or faintly coloured, smooth, thick-walled; annular abscission scar basal or sublateral, frequently with remains of sterigma or sporogenous cell forming a delicate, trailing membranaceous frill. Isolated from sandy paddy soil at 5-IO em depth in the State of Maranhao, Brazil. Cultures of the type have been deposited in the Mycotheca, University of Recife, Brazil; the Centraalbureau voor Schimmelcultures, Baarn, Netherlands, and the Cryptogamic Herbarium, University of Potchefstroom. Botryoderma rostratum grows well on various agar media such as PDA, PCA, CMA and MA. In all cases the more salient features of the colonies remain remarkably constant and uniform. The growth is moderately fast and spreading, reaching a diameter of 6.5-7 em in 14 days at 25°. On PDA the colonies are more restricted and compact" The young mycelial growth is delicately cottony and without colour in the dark but soon becomes rosaceous to rosy lilac when exposed to daylight and as sporulation commences. In age the colonies lose their original colour, eventually becoming a drab olive-brown. The vegetative mycelium is mainly immersed in the medium with only a sparse development of aerial mycelium. Fertile sporogenous areas are localized, resulting in a granular distribution of the fertile clusters in the mature colonies. In each fertile area sporulation is preceded by active branching of the hyphae followed by the appearance of numerous locally aggregated conidiophores and sporogenous cells. From each of these fertile clusters, sterile, setaceous and somewhat echinate hyphal ends radiate
New soil fungi. M. C. Papendorf and H. P. Upadhyay
263
freely (PI. 17, fig. 6). These structures are up to 200 pm long with an average length of 70-80 pm, become thick-walled in older cultures and are inclined to disintegrate when handled. The superficial spongy mat characteristic of the mature colony consists of dense assemblages of loosely arranged spore-bearing clusters. In older cultures this mat is sometimes completely covered by a darker hyphal growth obscuring its granular nature. Conidiophores and unicellular sporogenous cells are formed indiscriminately over the entire surface of the hyphae and hyphal branches excepting the extreme threadlike ends radiating freely from the fertile clusters (PI. 17, figs. 7,8). The sporogenous cells bear 1-4 conidia in basipetal succession (PI. 17, fig. 5) with the first spore normally initiated apically or subapically. When the first spore is formed subapically and the lateral spores sublaterally towards the apex it results in an apical group in which the sequence is not readily recognizable. Conidiophores may consist of more than one cell and are then cylindrical, torulose or somewhat irregular in shape. In most cases a multicellular conidiophore terminates in a sporogenous cell bearing the usual group of spores in basipetal succession while the subapical cells also produce conidia either singly and directly on the cells or in basipetal groups on laterally formed sporogenous cells. Where the conidiophores are fairly extensive the bearer cells are initiated in acropetal succession on the conidiophore with the entire structure ultimately forming a dense botryose cluster of sporogenous cells and conidia (PI. 17, figs. 7, 8). Large numbersof these spore-bearing elements are produced in close proximity in the dense fertile clusters typical of this genus. The conidia do not secede readily and usually do so individually by rupture of the sterigma or sporogenous cell, or in groups by separation of the bearer cell. Regarding the apparent thickness of the cell wall of the conidia it should be pointed out, as was done in the case of Melanophoma (Papendorf & du Toit, 1967) that this feature could be attributed to an illusion caused by a partial retraction of the cell contents from the inner surface of the wall. Crushed conidia with partly extruded plasm appear to have cell walls of normal thickness (PI. 17, fig. 10). This species is characterized mainly by the relatively rapid growth and rosaceous or rosy lilac colour of the colonies, the abundant, well differentiated conidiophores and broadly fusiform-ellipsoid, distally rostrate conidia, and the relatively long setaceous or spiniform hyphal ends radiating from "the spore bearing clusters. Botryoderma seems to be most nearly related to genera like Gilmaniella (Barron, 1964), and Ward!Jmyces and Asteromyces as described by Brooks & Hansford (1922) and MoreauSe Moreau (1941) respectively and further emended and validated by Hennebert (1962). Though differing in important features, these genera agree basically in producing their conidia more or less similarly in basipetal succession on a swollen sporogenous cell. In Wardomyces the sporogenous cell is swollen before sporulation commences, while Asteromyces is characterized by the swelling of the sporogenous cells as a result of successive development of conidia. According to Hennebert this fact influences and determines the position of these two genera in the present systems of classification as proposed by Hughes (1953) and
264
Transactions British Mycological Society
Tubaki (1958) causing their separation in different groups which have not yet been satisfactorily delimited. In a paper on Gilmaniella (Barron, 1964) and also in a personal communication in which reference is made to views expounded in his book, Professor Barron (1968) points out that he regards the spores of genera like Gilmaniella, Wardomyces, Echinobotryum and Asteromyces as aleuriospores in view of the fact that in all these forms the spore production is basically of the aleuriospore type and that the spores are released by rupture of the sporogenous cell. A separation of the forms producing solitary or botryose aleuriospores (Aleuriosporae) from those forming their conidia in basipetal chains from an annelated sporogenous cell (Annelophorae) is proposed. This would mean that the above-mentioned and similar genera should be included in Hughes's (1953) Section III of the Aleuriosporae. Since this applies equally well to Botryoderma it seems justified to place this genus in the same section. Regarding the sporogenous cell and the mode of spore production, Botryoderma shows a closer relationship to Gilmaniella and Wardomyces than to Asteromyces, In Botryoderma the size of the spore-bearing cell remains constant while producing only a limited number of spores in a basipetal succession which does not result in successive cruciate whorls of conidia as in Asteromyces. The attachment of the spores agrees more or less with that which is found in Gilmaniella and Wardomyces and more especially in W. hughesii, where each conidium is borne on a short denticle. In Botryoderma the conidia are generally more or less sessile or shortly stalked while the long denticles characteristic of Asteromyces are never present. In spore characters Botryoderma shows relationship to Gilmaniella, Wardomyces and Asteromyces. The spores agree with those of Wardomyces in being thick-walled and with those of Asteromyces in the absence of a germ slit or pore characteristically present in Wardomyces and Gilmaniella. In addition, Botryoderma has hyaline or only faintly coloured hyphae and conidiophores (sporogenous cells) like those of Wardomyces. From a comparison of these genera it is evident that Botryoderma shares features with Wardomyces, Asteromyces, Gilmaniella, Echinobotryum and others but at the same time differs so significantly that it is impossible to consider it congeneric with any. We feel greatly indebted to Professor G. L. Barron for his interest in this work, his valuable comments relating to the diagnoses and manuscript and for combining us in this undertaking; to Dr G. L. Hennebert for his kind advice and for proposing the name; to Dr J. A. von Arx for his generous support and encouragement; to Miss J. W. du Toit for making the drawings and photomicrographs, and to Mr H. W. Simpson for preparing the Latin diagnoses. The senior author wishes to acknowledge financial support from the South African C.S.I.R. and the Department of Agricultural Technical Services, Pretoria.
Trans. Br. mycol. Soc.
Vol. 52.
Plate 17
(Facing p. 265)
New soilfungi. M. C. Papendorf and H. P. Upadhyay
265
REFERENCES
BARRON, G. L. (1964). A new genus of the Hyphomycetes from soil. Mycologia 56, 5 14-518. BARRON, G. L. (1968). The genera of hyphomycetes from soil, xiii+364 pp. Baltimore: Williams and Wilkins. BROOKS, F. T. & HANSFORD, B. A. (1922). Mould growth upon cold-store meat. Trans. Br. mycol. Soc. 8, 113-142. HENNEBERT, G. L. (1962). Wardomyces and Asteromyces. Can. ]. Bot. 40, 12°3-1216. HUGHEs, S.J. (1953). Conidiophores, conidia and classification. Can.]. Bot. 31:,577-659. MOREAU, F. & MOREAU, F. (1941). Premiere contribution it l'etude de la microflore des dunes. Revue Mycol. N.S. 6, 49-g4. PAPENDORF, M. C. (1967a). Two new genera of soil fungi from South Africa. Trans. Br, mycol. Soc. 50, 69-75. PAPENDORF, M. C. (1967b). Leptodiscus afriaanus sp.nov, Trans. Br, mycol. Soc. 50, 687-69°. PAPENDORF, M. C. & DUTOIT,J. W. (1967). Melanophoma, anewgenusoftheSphaeropsidales. Trans. Br, mycol, Soc. 50, 503-506. PAPENDORF, M. C. & VON ARx, J. A. (1966). Herpotrichia striatispora, a new Ascomycete from South Africa. Nova Hedwiga 1:3, 395-397. RIDDEL, R. W. (1950). Permanent stained mycological preparations obtained by slide culture. Mycologia 42, 265-27°. TUBAKI, K. (1958). Studies of the Japanese Hyphomycetes. V. ]. Hattori bot. Lab. 20, 142 - 2 44. VAN DER AA, H. A. (1967). A new species ofCurvularia. Persoonia 5, 45-46. EXPLANATION OF PLATE
17
Figs. 1-4. Botryoderma lateritium. Figs. 5-10. B. rostratum. Fig. I. Young mycelium forming fertile clusters on agar plate. Fig. 2. Cluster showing sporogenous cells, apical conidia and spine-like hyphal ends. Fig. 3. Various basipetal groups of conidia on sporogenous cells. Fig. 4. Conidia. Fig. 5. Central area offig. 7 enlarged to show hyphae, conidiophores, sporogenous cells and young conidia. Note basipetal spore initiation. Fig. 6. Mature setose spore-bearing cluster. Figs. 7, 8. Conidiophores, sporogenous cells and young conidia. Note acropetal initiation of successive sporogenous cells on conidiophore (fig. 7, centre; fig. 8, left) and basipetal group of conidia (fig. 8, right). Fig. g. Intact conidia. Fig. 10. Crushed conidia showing effect on the apparent thickening of the wall.
(Accepted for publication
10
July 1968)