236 ENDOSPOREAE [ARCYR1A 



PI. 175. — a. sporangia; b. portion of sporangium-wall; c. capillitium and spore: 

 (California). 



This species lias been obtained hitherto from the western States of 

 North America only. It is allied to A. ferruginea, from the yellow form 

 of which it differs in shape, in the papillose thickenings of the spor- 

 angium-wall, and in the smoother spores. A. vitellina Phill. from 

 California is the same species. 



Hob. On (load wood.— California (B.M. 1495): Colorado (B.M. 

 3026). 



3. A. cinerea Pers. Syn. Fung., 184 (1801). Plasmo- 

 dium greyish-white. Total height 0-8 to 4 mm. Sporangia 

 stalked, gregarious or solitary, single or united in clusters of 

 two to six, ovoid or cylindrical, more rarely globose, 0-5 to 

 1-2 mm. diam., pale grey, greenish- or bluish-grey, or greyish 

 flesh-colour, sometimes dull yellow ; cup of the sporangium- 

 wall membranous, nearly smooth, minutely papillose or 

 reticulated, plaited at the base, pale grey or yellowish. Stalk 

 cylindrical, furrowed, 0'2 to 2 mm. long, 0-05 to 0-15 mm. 

 thick, dark grey or brown, hollow, filled with spore-like cells. 

 Capillitium a close network of grey or yellowish-grey threads ; 

 the upper and middle threads 2 to 4^ thick, closely 

 warted, transversely banded, or spinulose, the spines often 

 stouter and larger on one side ; the threads composing the 

 basal part of the network 4 to 6 /x thick, either smooth, faintly 

 warted or reticulated, with numerous attachments to the cup. 

 Spores almost colourless, marked with a few scattered warts, 

 6 to 8 /u. diam.— Rost. Mon., p. 272 ; Mass. Mon., 151 ; Macbr. 

 N. Am. Slime-Moulds, 196. Trichia cinerea Bull. Champ., 

 120 (1791). Stemonitis cinerea Gmel. Syst. Nat., 1467 (1791). 

 8. glauca Trentep. in Roth Catal. Bot., i. 221 (1797). 

 S. digitata Schwein. in Trans. Amer. Phil. Soc, n.s. iv. 260 

 (1832). Arcyria albida Pers. in Roemer N. Mag. Bot., i. 90 

 (1794) ; Lister Mycetozoa, 186. A. straminea Wallr. Fl. Crypt. 

 Germ., iv. 383 (1833) ? A. trichioides Corda Icon., ii. 23, 

 t. 12, fig. 86 (1838). A. bicolor Berk. & Curt, in Journ. Linn. 

 Soc, x. 349 (1869). A. pallida Berk. & Curt, in Grev., ii. 67 

 (1873). A. digitata Rost. Mon., p. 274 (1875) ; Macbr. N. Am. 

 Slime-Moulds, 197. A. stricta Rost. Mon., App. p. 36 (1876). 

 A. Friesii Berk. & Br. in Ann. Mag. Nat. Hist., ser. 4, xvii. 

 140 (1876). A. Cookei Mass. I.e., 154 (1892). A. tenuis 

 Schroet. in Hedw., xxxv. 207 (1896). Lachnobolus Arcyrella 

 Rost. Mon., p. 431 (1875) ? 



Var. earned Lister : sporangia clavate or cylindrical, flesh- 

 coloured ; capillitium marked with a loose spiral of flat-topped 

 or almost hooked spinules, minutely warted elsewhere, basal 

 threads almost smooth or faintly reticulated. 



PI. 176. — a. b. sporangia ; c. globose sporangium on bramble stalk ; d. d 1 . outer 

 threads of capillitium ; e. spore ; (England). 



