Fungi. ] 



PLORA OP NEW ZEALAND. 



191 



Gen. XXXII. ^THALIUM, Li. 



Peridium indeterminatum, membranoso-cellulare, fragile, fatiscens, extus strato floccoso evanesceute 

 corticatum, intus e fioccis in strata membranacea coalitis cellulosum. 



The only species of this genus, which is the pest of hothouses, occurs under various forms in various situations. 

 How far it may be right to combine them all is doubtful, without a comparative examination of their fruit, which, 

 has not at present been made. (Name from aSakr}, soot.) 



1. iEthalium septicum, Pr. Syst.Myc. v. 3. p. 93. 



Hab. On various substances, as dead wood, moss, etc., Colenso. 



Gen. XXXIII. DIDERMA, Pers. 



Peridium duplex : exterius crustaceum, discretum, glabrum, fragile, dehiscens : interius tenerrimum, 

 menibranaceum, evanescens. Flocci vagi, versus basin adnati, aut saepius columellas affixi interque sporas 

 compactas serpentes, raro latentes. 



The minuter exotic Fungi, especially those which scarcely bear transmission, have for the most part been little 

 examined, and therefore much cannot be said about their distribution. The smooth, polished outer peridium suffi- 

 ciently distinguishes the genus from any with which it can be confounded. Pew objects are more beautiful when in 

 perfection. (Name from Sis, double, and Sep/xa, a skin.) 



1. Diderma Eooieri, Berk.; rufum, stipite brevi crasso sursum angustiore, peridio globoso sursum 

 evanesceute deorsum subcircumscisso interiore tenerrimo hyalino, exteriore membranaceo, capillitio subhya- 

 lino, sporis atris sub lente vinosis. (Tab. CV. Kg. 12.) 



Hab. On fronds of Hymenophyllum, in woods of the interior of the Northern Island, Colenso. 



About a line high including the stem, rufous, with a slight iridescent lustre. Stem, about equal in length to 

 the globose peridium, thick, attenuated upwards, slightly veined. Peridium evanescent above, persistent at the base ; 

 outer membranous, subplicate ; inner extremely delicate, nearly colourless ; columella obtuse, about half the length 

 of the stem, like which it is slightly veined, dark rufous. Capillitium attached to the columella and inner mem- 

 brane, branched with broad, triangular spaces or lacunae. Spores globose or polyhedrous, about TT V„ of an inch in 

 diameter, black when seen in a mass, vinous under the lens. — This species resembles a Pliysarum in its outer mem- 

 brane, but there is a strong columella, and a distinct inner membrane, visible only on dissection, to which the capil- 

 litium is attached. The inner membrane is certainly not composed of fibres, but that is rather the case with the 

 outer membrane, as also with the base of the stem.— Plate CV. Pig. 12. Diderma Hookeri, natural size, a, b, the 

 c. Portion of the double coat, and the annexed threads, d. Spores, magnified 250 diameters. 



Gen. XXXIY. DIDYMIUM, Schrad. 



Peridium menibranaceum, tenue, inegulariter dehiscens aut fatiscens, tectum, cortice (peridio externo 

 non discreto) adnato in squamulas furfuraceas aut villum farinosum mox fatiscente. Flocci vagi, peridio 

 adnati, inter sporas serpentes. 



The mealy peridium distinguishes this genus, which is of much more frequent occurrence than the former. It 

 contains many very elegant species. (Name from SiSvpos, double.) 



1. Didymium australe, Berk. ; peridio subgloboso fragili farinaceo, stipite brevissimo nigrescente, co- 

 lumella pallida, fioccis crispis, sporis majoribus atris. 



Hab. On the under side of leaves of Lomaria Colensoi, Colenso. 

 Minute, fixed by a thin, pale hypothallus. Stem extremely short, nearly black, even. Peridium subglobose 



