48 F.NDOSPOKE/B. [pHYSARUM. 



P. galbeum Wing., Ell. & Everh., N. Am. Fung., 2491. P. Petersii 

 Mass., Mon., p. 295 (in part). 



Plate XII., B.—a. sporangia, x 20; b. capiUitium and spores, x 280; 

 0. spore, X 600 (United States). 



The red-brown stalks and the larger expansions of the oapillitium 

 at the axils of the branches distinguish this species from P. viride. 

 P. galbeum Wing.^ (L:B.M.24) has globose orange-yellow sporangia, 

 and orange-brown stalks entirely free from lime ; the capiUitium is a 

 close network of threads expanded and flattened at the axils, with few 

 or no deposits of lime. Similar forms have been found near Lyme 

 Regis. They are here included under P. Berkeleyi, but other 

 gatherings from Lyme Regis connect these forms with P. viride, making 

 it doubtful whether P. BerJceleyi is not merely a marked variety of 

 that species, The specimen from Iowa (B. M. 1017) resembles the 

 type of P. galbeum, except that the capiUitium consists of a close net- 

 work of large branching knots, densely charged with yellow lime- 

 granules, connected by few branching hyaline threads ; the spores 

 measure 8 fi. This form is nearly related to a specimen from Moss- 

 man's Bay, Sydney, Australia (K. 346), marked Tilmadoche mutaUUs, 

 with capiUitium of a Badhamia-like character, the threads being 

 charged throughout with yellow lime-granules ; the spores are spinulose 

 and measure 10 to 13 y.. This is connected with P. viride by a series 

 of intermediate specimens from Ceylon (also in Kew Herb.) with 

 unusually extended lime-knots and large spores, but the rigid persis- 

 tent capiUitium brings it under the definition of P. BerJceleyi. 



Hob. On dead wood. — Swan River, Australia (K. 1328) ; Iowa 

 (B. M. 1017) ; So. Carolina (B. M. 439, 870, 993) ; Massachusetts 

 (L:B.M.24). 



16. P. polymorphum Ex)st., Men., p. 107 (1875). Plasmodium 

 occurring in masses of decaying leaves or in rotten logs, at first 

 colourless, as it emerges for fructification white, then yellow, 

 spreading far over all adjacent objects (Macbride). Total height 

 1-5 to 2 mm. Sporangia much compressed, lenticular, and um- 

 bilicate, undulate, or lobed convolute and often confluent, stipitate, 

 solitary or in clusters of 5 to 10 together, grey or yellow; 

 sporangium-wall membranous, with scattered thin innate clusters 

 of white or yellow lime-granules. Stalks subulate, slender, inclined, 

 often fasciculate, 5 to 10 combined, yellow or tawny, translucent, 

 without deposits of lime. Columella none. Oapillitium ai loose 

 network of delicate threads with many flat expansions at the axils ; 

 lime-knots yellow, very variable in shape, size, and abundance. 

 Spores violet-brown, minutely spinulose, 8 to 10 /a diam. — Mass., 

 Mon., "p. 283. Didymium polymorphimi Mont., in Ann. Sci. Nat., 

 Ser. 2, vui., p. 361 (1837). Didymium luteo-griseitm Berk. & Curt., 

 in Grev., ii. (18"73), p. 65. Didymium obrussevm Berk. & Curt., in 

 Journ. Linn. Soc, x., p. 348 (1869). Physarwm ohrusseum Eost., 

 Mon., App.,p. 11. Didymium tenerrimumBevk & Cui-t., I.e.; Mass., 

 Mon., p. 247. D. gyrocephahim Mont., in Ann. gci. Nat., Ser. 2, 

 viii., p. 362. Tilmadoche gyrocephala Eost., Mon., 131; Mass., 

 Mon., p. 335; Macbride, in-BuU. Nat. Hist. Iowa, 1892, p. 152. 



a. obrusseum; sporangia simple. 



p. gyrocephalum : sporangia clustered. 



