112 ENDOSPOREAE [DIDERMA 



13. D. radiatum Lister. Plasmodium white or pale 

 yellow, rarely coral-red. Sporangia scattered or crowded, 

 subglobose or hemispherical and depressed, flattened or 

 umbilicate beneath, stalked or sessile, smooth or somewhat 

 wrinkled and rimose, 0*5 to 1*2 mm. diam., pale grey, white, 

 brownish or red-brown ; sporangium-wall dehiscing either 

 irregularly or in a stellate manner by revolute lobes, white 

 or pale brown on the inner side ; the outer layer cartilaginous, 

 with granular deposits of lime, not always closely connected 

 with the membranous inner layer. Stalk ochraceous, white, or 

 brown, 0-2 to 0*6 mm. high, usually short and stout, enclosing 

 white lime deposits. Columella hemispherical or subglobose, 

 0-5 mm. diam., densely calcareous. Capilhtium abundant, 

 dark violet-brown, radiating from the columella in somewhat 

 rigid threads, sparingly branched except at the colourless 

 extremities, rarely pale slender and flexuose. Spores dark 

 violet-brown, closely and minutely spinulose, 8 to 12 fx 

 diam — Lycoperdon radiatum L. Sp. PI., ed. 2, 1654(1763). 

 Didymium stellare Schrad. Nov. PI. Gen., 21, t. v, figs. 3, 4 

 (1797). D. Geaster Link in Mag. Ges. Nat. Fr. Berk, vii. 42 

 (1815). D. complanatum Fuck. Sym. Myc, 341 (1869). Diderma 

 stellare Pers. Syn., 164 (1801) ; Macbr. N. Am. Slime-Moulds, 

 104. D. umbilicatum Pers. I.e., 165. D. crassipes Schum. 

 Enum. PL Saell., ii. 196 (1803). D. Carmichaelianum Berk, in 

 Sm. Engl. Fl., v. pt. 2, 311 (1836). D. concinnum Berk. & Curt. 

 in Grev., ii. 52 (1873), see Journ. Bot., xxxv. 212. Leangium 

 stellare Link I.e., hi. 26 (1809). Cionium stellare Spreng. 

 Syst. Orb. Veg., iv. 529 (1827). Chondrioderma radiatum 

 Host. Mon., p. 182 (1875) ; Mass. Mon., 200 ; Lister 

 Mycetozoa, 83. C. Carmichaelianum Cooke Myx. Brit., 42 

 (1877) ; Mass. Mon., 202, in part. 



PI. 93. — a. pale sporangia (Devon) ; b. sporangia dehiscing irregularly and showing 

 the hemispherical columella ; c. capillitium and spores with fragment of the spor- 

 angium-wall ; d. spore. 



PI. 94. — a. dark sporangia with walls dehiscing in lobes (Northumberland) ; b. 

 capillitium and spores. 



This variable species presents three well-rnarked forms. One, 

 represented by the type of Lycoperdon radiatum in the Linnean 

 Herbarium, London, has brown often mottled sporangia whose walls 

 dehisce in a stellate manner (fig. 94a). The second has pale grey or 

 drab sporangia that dehisce irregularly (fig. 93a) ; this is the commonest 

 form in the British Isles, and was described by Persoon as a distinct 

 species, D. umbilicatum, but gatherings of intermediate character 

 frequently occur, and Rostafinski appears to have been justified in 

 uniting these ferns under one name. A third form has nearly white 

 sporangia ; the outer layer of the wall separates easily from the 

 membranous inner layer, and the spores measure 8 to 9 yu. ; it has been 

 named var. album by Torrend (Fl. Myx., 168). The development of 

 lime varies in different gatherings and often in individuals of the same 

 cluster ; the wall instead of being obscurely granular, as is usually 



