THE GASTEROMYCETES OF AUSTRALASIA. XV. The Genera Mesophellia and Castoueum. By G. H. Cunningham, Mycologist, plant Research Station, Palmeiston Nortii, N.Z. (Plate vi.) [Read 2Sth September, 1932.] A study of the literatui-e shows that those who have worked with the Gasteromycetes have had difficulty in classifying the genera Mesophellia and Castoreum (including Diploderma) . Thus de Toni (1888, p. 48) placed Mesophellia under the subfamily Podaxineae, ''Diploderma" under the Diplodermeae, and Castoreum under the Sclerodermeae; and this arrangement was followed by Cooke (1892, p. 222, 232, 242). Fischer (1900, p. 338, 342) placed Castoreum under his "Ungenuegend bekannte Gattungen" of the Sclerodermaceae, and ■'Diploderma'''' and Mesophellia under a similar section of the Calostomaceae. ..tjloyd (1905, p. 5) placed Castoreum and Mesophellia under his tribe 5-Anomalae (defined as "not allied to previous tribes or to each other"), but did not mention ''Diplodervia". And in later papers he frequently commented on the difficulty of assigning these genera to a satisfactory position, claiming that their spores and tjlebal colour suggested affinities with the Phallales, and their hypogaean habit with the Hymenogastraceae. Dodge (1929) considered Mesophellia to be an Ascomycete, and placed the genus under the tribe Mesophellieae of the Elapho-mycetaceae (one of the hypogaean Tuberales). As will be shown, these genera exhibit little relationship to the Scleroder-iiuiceae, less to the Diplodermeae (as defined by de Toni), and none to the Calostomaceae, Podaxaceae or Elaphomycetaceae, but are in reality members of the Lycoperdaceae. I have recently worked over 34 collections loaned by Dr. J. B. Cleland, Adelaide, and Mr. L. Rodway, Hobart, and from this material (representing about 160 plants altogether), have been able to work out the following particulars regarding the species of these two interesting genera. Structure of the Mature Plant. In Mesophellia plants are hypogaean, being exposed apparently accidejitally l»y marsupials or as a result of cultural operations. The peridium of the species studied is two-or thi'ee-layered, and encloses a pulverulent gleba of capillitium and spores. The exoperidium is in the nature of a firm, relatively thick (2-3 mm.) tissue composed exteriorly of sand, earth or vegetable debris cemented to a firm fibrous tissue in which the hyphae appear to be aggregated into fascicles. The exterior, especially, varies considerably in appearance, toughness and thickness, accoi-ding to the substratum in which the plant has developed. The endoperidium is a firm, parchment-like membrane, about 0-25 mm. in thickness (2 mm. thick in M. castanea), composed of a pseudoparenchyma of closely woven, partly gelatinized
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