130 BNDOSPOREAE [DIDYMIUM 



it is, however, very constant in its characters from different parts of 

 the world, being distinguished by the smaller sporangia and more slender 

 capilLtium ; it often bears a considerable resemblance to D. nigripes, 

 and is named " D. microcarpum " Rost. (a synonym for D. nigripes) in 

 some specimens in Strassb. Herb. ; the opaque granular stalk distin- 

 guishes it from that species and its allies. Forms sometimes occur with 

 the upper part of the stalk as well as the columella pale brown and 

 filled with crystalline nodules of lime. Rostafinski's specimen of D. 

 physaroides in the Strassb. Herb, appears to be an imperfect develop- 

 ment of D. melanospermum ; the spores, many of which are abnormal 

 in shape and size, 15 to 50 ft long, are combined in agglutinated 

 masses, and the capillitium contains vesicular expansions filled with 

 lime such as are not unfrequent in imperfect growths of Didymium ; 

 the sporangia are mostly clustered and confluent, but in some cases 

 they are solitary ; the columella is dark brown and chambered, and 

 the sporangium-wall is mottled with purple-brown. 



Hab. On dead wood, twigs and leaves, especially of Conifers. 

 Common. — Highgate, London (B.M. 1068) ; Lyme Regis, Dorset (B.M. 

 1333) ; Ascot, Berks (B.M. 70) ; North Wales (B.M. 2476) ; near Aber- 

 deen (B.M. 2477) ; France (B.M. 1977) ; Germany (B.M. 422); Zurich 

 (B.M. 1560) ; Portugal (B.M. 2478) ; Bohemia (Herb. Celakovsky) ; 

 Mt. Ruwenzori, Africa (B.M. 1164) ; New Zealand (B.M. 2485); Maine, 

 U.S.A. (B.M. 1603) ; Georgia (B.M. 2480) ; South Carolina (B.M. 889) : 

 var. minus — Lyme Regis (B.M. 1334) ; France (B.M. 2481) ; Portugal 

 (B.M. 2486); Nigeria (B.M. 2482); Java (B.M. 2483); Antigua 

 (B.M. 2484) ; Ohio (B.M. 1336) ; South America (B.M. 2487). 



8. D. nigripes Fries Syst. Myc, iii. 119 (1829). Plas- 

 modium grey or colourless. Total height 1 to 1*5 mm. Spor- 

 angia gregarious, hemispherical, umbilicate beneath, stalked, 

 erect, 05 to 0*7 mm. diam., white ; sporangium-waU mem- 

 branous, mottled with brown or colourless, beset with stellate 

 crystals of lime. Stalk cylindrical, one to three times the 

 height of the sporangium, longitudinally striate, varying in 

 colour from dark olive-brown to orange-brown, translucent, 

 not containing refuse matter. Columella subglobose, dark 

 brown, filled with irregular angular crystals of lime. Capilli- 

 tium of dehcate colourless or purplish-brown branching threads. 

 Spores pale violet-brown, nearly smooth, 8 to 11 /x diam. — 

 Berk, in Sm. Engl. Fl., v. pt. 2, 313 ; Macbr. N. Am. Slime- 

 Moulds, 90. Physarum nigripes Link in Mag. Ges. Nat. Fr. 

 Berl., iii. Diss. 1, p. 27 (1809) ; Ditm. in Sturm Deutsch. Fl., 

 Pilze, 85, t. 42 (1817). P. microcarpon Fr. Symb. Gast., 23 

 (1818). Didymium microcephalum Chev. Fung. & Byss. 111., 

 fig. 2 (1837). D. porphyropus Dur. & Mont. Fl. Alg., 409 (1846). 

 D. microcarpon Rost. Mon., p. 157 (1875) ; Mass. Mon., 226. 

 D. tenue Pat. in Bull. Soc. Myc, iv. 96 (1888). 



Var. eximium Lister : stalk dark orange, columella orange 

 or buff ; sporangium-wall firm, usually buff. — D. megalo- 

 sporum Berk. & Curt, in Grev., ii. 53 (1873). D. eximium 



