Notes and brief articles NOTES ON THE CONIDIAL STATE OF HYPOXYLON UDUM A. J. S. WHALLEY Department of Biology, Sunderland Polytechnic, Sunderland Hypoxylon udum Pers. ex Fr., an apparently rare species restricted to the British Isles and Europe, is usually found on wet decaying decorticated oak wood. It is very similar to H. confiuens (Tode ex Fr.) Westd. in macroscopic stromatal characters but has much larger ascospores which are A ＳＰｾｭ B oa OC ｭｾＵ Fig. 1. Hypoxylon udum. (A), Ascospores; (B), mature conidiophore; (C), conidia. Trans. Br, mycol. Soc. 67 (3), (1976). Printed in Great Britain Notes and brief articles 516 Fig. 2. Hypoxylon udum conidiophores ( x 4,200). ellipsoidal to oblong with obtuse ends, or sometimes with a rounded protuberance at one end (Fig. 1A). The spores measure (22) 26-35 x 9-13 pm and possess an oval, laterally placed germ pore which Munk (1957) has suggested demonstrates a distinct affinity to Amphisphaerella (Sacc.) Kirsch. Miller (1961) placed H. udum in the Primocinerea subsection together with H. serpens Pers. ex Fr. and H. confluens. The two latter species have geniculate conidial states, and the genus Geniculosporium based on G. serpens was erected to accommodate these and similar imperfect fungi Trans. Br, mycol. Soc. 67 (3), (1976). (Chesters & Greenhalgh, 1964). There have been few collections of H. udum this century but a recent collection from Dinnet Oak Wood, Aberdeenshire enabled successful germination of ascospores and subsequent examination of the conidial state. At first the ascospores failed to germinate until pretreated with dry heat at 60 °C for 15 min as recommended by Jong & Rogers (1972). The cultures obtained are slow growing on 2 % malt extract agar, and are initially white to grey in colour becoming creamy brown to orange with Printed in Great Britain Notes and briefarticles age, often with conspicuous zonation. Sporing areas are limited to small pustular regions which are greyish in colour. The conidia are unicellular, ovoid to elliptical, truncate at the base, hyaline to subhyaline, and measure 3-6 x 2-4 11m. They are aerogenous blastospores produced in continuous succession at the apex of the conidiophore. The conidiophores are indeterminate, dichot omously branched, pigmented, distinctly geniculate, and mostly 2-4 pm wide (Fig. 2). It is therefore apparent that conidial H. udum is geniculate and similar ·to conidial H. serpens and H. confiuens and if a genetic name is required it is suggested here that it could be accommodated in REFERENCES GREENHALGH , G. N. (1964). Geniculosporium serpens gen. et sp .nov ., the imperfect state of Hypoxylon serpens. Transactions of the British Mycological Society 47, 393-401JONG, S. C. & ROGERS, J. D. (1972). Illustratious and descriptions of conidial states of some Hypo xyon species. Wa shington Agricultural Experiment Station. Technical Bulletin 71, 51 pp. MILLER, J. H. (1961). A monograph of the world species of Hypo xylon , Athens, U .S.A.: University of Georgia Press . MUNK, A. (1957). Danish Pyrenomycetes. Dansk botanisk Arkiv 17, 1-491. CHESTERS, C . G . C . & Geniculosporium. THE GENUS HYPOXYLON IN UGANDA FORESTS H. K. TALIGOOLA Department of Botany, Makerere University, Kampala, Uganda AND A. J. S. WHALLEY Department of Biology, Sunderland Polytechnic, Sunderland The documentation of the fungus flora of Uganda has barely begun. Masefield (1940) noted that the chief difficulty faced by mycologists in Uganda was the lack of literature and records of previous fungal collections. This is still true today. The meagre and scattered records available are those made by plant pathologists and a few mycologists sent out by the British Colonial Office to deal mainly with plant diseases important in developing an agricultural economy for Uganda. Among the notable accounts of Ugandan fungi is that of Smith (1895), based on studies of fungi collected by Scott Eliot during the Ruwenzori mountain expedition. Ma itland & Wakefield (1917) publi shed a list of saprophytic fungi, mainly macrofungi, from certain Uganda forests, and later Wakefield (1920) listed the parasitic microfungi on cultivated and wild plants . Hansford published a series of papers (Hansford 1937, 1938, 1940 - 1 , 1943, 1944, 1945, 1946a, 1946b) on the fungus flora of Uganda covering various groups of the Ascomycetes and Fungi Imperfecti, induding information on the foliicolous ascomycetes, their parasites and associated fungi. Wakefield & Hansford (1948- 9) listed the U redinales of Uganda and more recentl y Pegler (1966) described a number of agarics from the Mp anga forest area. The present publication is part of a study on saprophytic Ascomycetes and Fungi Imperfecti on dead and decomposing branches , logs and Tran s. Br. my col. Soc. 67 (3), (1976). stumps in three Uganda forests : Mabira forest km east, Zika forest 25 km south, and Mpanga forest 35 km south-west, of Kampala the capital city. All three forests are only a few kilometres from the shores of Lake Victoria and are within the equatorial region; they therefore receive some of the highest amounts of rainfall in Uganda. Whalley & Taligoola (1976) published information on species of Hypoxylon from Uganda and the results in this paper form the second part of this study. It is intended to publish information about other genera of the Xylariaceae, Nectriaceae and Fungi Imperfecti later. Mpanga and Zika are fairly small forests, of 600 ha and less than half that area respectively, and the area covered during collecting probably gives a fair representation of the species composition of the ascomycete flora. However, Mabira is a very large forest of about 300 km 2 and collecting was done in two places only, an annual collection at Buwola village around picnic site No . 1 on the Kampala-}inja road, and a single collection at Namanyama Village in April 1971. Further collecting from Mabira forest may therefore change the estimate of the representation of some of the species. Most collections were made during and after the first heavy rains between April and }uly of each year in the period 1970-3 inclusive. The specimens were collected from each of the forests 50 Print ed in Great Britain