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Note on the occurrence of species of Oidiodendron Robak in Britain
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NOTE ON THE OCCURRENCE OF SPECIES OF OID10DENDRON ROBAK IN BRITAIN By G. SMITH, London School
of Hygiene and Tropical Medicine
The genus Oidiodendron was erected by H. R ob ak (1932) on three species which were all found growing on ground wood-pulp in Norwegian mills. The original three species are O. nigrum, O. fus cum and O. rhodogenum, the last being readily distinguished by its production of a blood-red diffusible pigment in wort aga r culture s. Later, Robak (in Melin & Nannfeldt, 1934, p. 440) described a fourth species, O. griseum, and a further addition to the genus was made by von Szilvinyi (1941) with his O. jlavum. The genus is char act erized by erect, arborescent conidiophores, with bran ching always monopodial, and by the differenti ation of the terminal br an ches, from th e tip inwards, into conidia. Sup erficially the fructification s resemble, except for their smaller size, those of Cladosporium (Hormodendron), but th e method of spore production relates th e genus to Oidium and Torula Pers. So far as I can ascerta in there have been , up to th e present, no records of Oidiodendron for Brit ain. * Between 1923 and 1930 a considerable number offungi, mostl y H yphom ycetales, were collected for biochemical studies in th e resear ch laboratories of Nobel's Expl osives Co. Ltd. , at Ardeer, and in 1931 the collection of cultures was tra nsferred to the London School of H ygiene and Tropi cal Medicine. Two of th e cultures, both of which were cata logued as ' Hormodendron or ? Cladosporium' , obviously differed in cultural characteristics from typical Cladosporium herbarum, but no atte mpt was made to identify them until, recentl y, one of them was shown to have interesting biochemical properties. Culture Ag 109. This was isolated by the lat e J. H. V. Charles from a lichen on a wood en post, in December 1926. It is a typical str ain of O. rhodogenum Robak. Growth on all culture media is very slow, almost velvety or tufted floccose, pale grey, with overgrowth of dirty white sterile mycelium. On corn-meal agar or wort agar th e whole mass of medium is gradually coloured blood-red. On other media pigment production is sparse and spasmodic. Culture Ag 112. Isolated by the late J. H. V . Ch arl es, April 1928, from gun cotton at Ard eer . Gr owth is very slow, grey to fuscous, powder y, with some dirty brown pigment in th e medium. It agrees well with O.fuscum Robak. Another strain of O.f uscum has recently been received from Dr A. Burges, Cambridge, am ongst a batch of Penicillium cultures for identifi cation. It was isolated in October 1945, from the sur face humus in a pine plantation
* Since th is Note was su bmitted for publicati on Denni s and Wakefield ( T rans. Brit. Mycol. Soc. 1946, XXIX, 141) ha ve described a British strai n of O.fuscum Robak.
Oidiodendron Robak in Britain. G. Smith
233
at Wangford Warren, near Brandon. Dr Burges reports that he has, in addition, three other isolations from the same locality. In view of the simila rity of this genus , in gross appearance of the conidi al fructifications, to Cladosporium, it seems probable th at a search through the records of Cladosporium would bring to light other instances of th e occurrence of species of Oidiodendron in Britain. I am greatly indebted to Mr E. W. Mason, who identified the strain Ag 112 as Oidiodendron, and drew my attenti on to Robak' s paper.
REFERENCES MELIN, E. & NANNFELDT,J. A. (1934)' Researches into the blu eing of ground woodpulp. Saertryck ur Svenska Skogsuardsforeningens Tidskrijt, Hafte III , IV,' 397-6 1 6. ROBAK, H. (1932). Investigations regarding fungi on Norwegian ground woodpulp and fungal infections at woodpulp mills. Saertrykk av Nyt Magazin for Naturoidenskabeme, LXXI, 185-33°. VON SZILVINYI, A. (194 1). Mikrobiologische Bodenuntersuchungen im Lunzer Gebiet. :Cbi. Bakt. Abt. II, ern, I33-89.
(Acceptedf or publication 24 July 1946)
NOTE ON THE OCCURRENCE OF SPECIES OF OID10DENDRON ROBAK IN BRITAIN By G. SMITH, London School
of Hygiene and Tropical Medicine
The genus Oidiodendron was erected by H. R ob ak (1932) on three species which were all found growing on ground wood-pulp in Norwegian mills. The original three species are O. nigrum, O. fus cum and O. rhodogenum, the last being readily distinguished by its production of a blood-red diffusible pigment in wort aga r culture s. Later, Robak (in Melin & Nannfeldt, 1934, p. 440) described a fourth species, O. griseum, and a further addition to the genus was made by von Szilvinyi (1941) with his O. jlavum. The genus is char act erized by erect, arborescent conidiophores, with bran ching always monopodial, and by the differenti ation of the terminal br an ches, from th e tip inwards, into conidia. Sup erficially the fructification s resemble, except for their smaller size, those of Cladosporium (Hormodendron), but th e method of spore production relates th e genus to Oidium and Torula Pers. So far as I can ascerta in there have been , up to th e present, no records of Oidiodendron for Brit ain. * Between 1923 and 1930 a considerable number offungi, mostl y H yphom ycetales, were collected for biochemical studies in th e resear ch laboratories of Nobel's Expl osives Co. Ltd. , at Ardeer, and in 1931 the collection of cultures was tra nsferred to the London School of H ygiene and Tropi cal Medicine. Two of th e cultures, both of which were cata logued as ' Hormodendron or ? Cladosporium' , obviously differed in cultural characteristics from typical Cladosporium herbarum, but no atte mpt was made to identify them until, recentl y, one of them was shown to have interesting biochemical properties. Culture Ag 109. This was isolated by the lat e J. H. V. Charles from a lichen on a wood en post, in December 1926. It is a typical str ain of O. rhodogenum Robak. Growth on all culture media is very slow, almost velvety or tufted floccose, pale grey, with overgrowth of dirty white sterile mycelium. On corn-meal agar or wort agar th e whole mass of medium is gradually coloured blood-red. On other media pigment production is sparse and spasmodic. Culture Ag 112. Isolated by the late J. H. V . Ch arl es, April 1928, from gun cotton at Ard eer . Gr owth is very slow, grey to fuscous, powder y, with some dirty brown pigment in th e medium. It agrees well with O.fuscum Robak. Another strain of O.f uscum has recently been received from Dr A. Burges, Cambridge, am ongst a batch of Penicillium cultures for identifi cation. It was isolated in October 1945, from the sur face humus in a pine plantation
* Since th is Note was su bmitted for publicati on Denni s and Wakefield ( T rans. Brit. Mycol. Soc. 1946, XXIX, 141) ha ve described a British strai n of O.fuscum Robak.
Oidiodendron Robak in Britain. G. Smith
233
at Wangford Warren, near Brandon. Dr Burges reports that he has, in addition, three other isolations from the same locality. In view of the simila rity of this genus , in gross appearance of the conidi al fructifications, to Cladosporium, it seems probable th at a search through the records of Cladosporium would bring to light other instances of th e occurrence of species of Oidiodendron in Britain. I am greatly indebted to Mr E. W. Mason, who identified the strain Ag 112 as Oidiodendron, and drew my attenti on to Robak' s paper.
REFERENCES MELIN, E. & NANNFELDT,J. A. (1934)' Researches into the blu eing of ground woodpulp. Saertryck ur Svenska Skogsuardsforeningens Tidskrijt, Hafte III , IV,' 397-6 1 6. ROBAK, H. (1932). Investigations regarding fungi on Norwegian ground woodpulp and fungal infections at woodpulp mills. Saertrykk av Nyt Magazin for Naturoidenskabeme, LXXI, 185-33°. VON SZILVINYI, A. (194 1). Mikrobiologische Bodenuntersuchungen im Lunzer Gebiet. :Cbi. Bakt. Abt. II, ern, I33-89.
(Acceptedf or publication 24 July 1946)