Didym'inm. 229 



(?) Physarum alatum, Fr., 1. c, iii., p. 132 (1829). 

 Diclymium costatum, Fckl., Syni. Myc. I., Nach., p. 339. 



Didymium discoideum, Rost. 



Sporangia dueoid, almost sessile, umbilicate, inferior part of 

 wall violet, superior spotted, with irregular pellucid veins, 

 breaking away after maturity in small patches ; stem from its 

 shortness scarcely apparent, hid in the iimhilicus, dilated at the 

 base into a circular hypothallus; columella discoid or hemi- 

 spherical, like the stem yellowish Jlesh-colour ; threads of capil- 

 litium flexuous, rarely forking, bay, tips colourless; spores 

 strongly wartcd, blackish-violet, 11 — 13 ju diameter. 



Didymium discoideum, Rost., Mon., p. 162; Sacc, Syll., no. 

 1305. 



Germany. 



* * SpiOTCs smooth. 



Didymium radiatum, B. and C. (figs. G8 — 72). 



Scattered, sporangia vertically compressed, not umbilicate, but 

 sometimes slightly depressed below, dark grey, with crowded, 

 small, white, innate patches of lime, dehiscing irregularly ; 

 stem longer than height of sporangium, slightly attenuated 

 upwards, white or pale grey, expanding into a smcdl, circular 

 hypothallus, longitudincdly costctte, the ribs passing in a radiate 

 manner into the hyjjothallus ; columella brownish, much com- 

 pressed; capillitium abundant, radiating from the columella to 

 the wall of the sporangium, tlireads thin, brownish-lilac, some- 

 times forked; spores globose, lilac, smooth, 8 — 10 ix diameter. 



Didymiuiih radiatum, B. and C, Journ. Liim, Soc, vol. x., 

 p. 348; Sacc, Syll., n. 1328. 



(Type in Herb. Berk., Kew, no. 107G5.) 



Didymium commutahile, B. and Br., Journ, Linn. Soc, v. xiv., 

 p. 83; Sacc, Syll., n. 1300; Rost., App., p. 21. 

 (Type in Herb. Berk., n. 10766.) 



Didymium botryoidcs. Berk, in Herb. 



/. gcniduum. Simple, scattered ; stem usually lunger than 

 sporangium. 



