PERICH^ENA.J ARCYRIACE^E. 199 



of P. fusco-atra in the collections difPer in no respect from forms of 

 P. popidina, and cannot be held as specifically distinct. The type 

 specimen of Oligonema Broomel Mass, from Warleigh (B. M. 364) 

 is typical P. popul'ma with characteristic branching capillitium threads 

 marked with irregular swellings and spinules, and with minutely and 

 closely warted spores 14 to 15 /u, diam. The specimen described by 

 Cienkowski as Licea pannornm^ I.e., is given by Rostafinski as the 

 type of a new species, Perichcena liceoides, characterised by the scanty 

 capillitium of free threads and the spores measuring 9 to 10 p. ; Zopf , 

 on the other hand, quotes it as a synonym for P. popul'ma ; and this 

 view is confirmed by the not infrequent occurrence of forms of the 

 latter species with scanty or no capillitium, and spores measuring from 

 10 to 12 p.. 



Hal}. On dead wood and bark. Batheaston, Somerset (B. M. 309, 

 320) ; Shrewsbury (B. M. 322) ; Lyme Regis, Dorset (L:B.M.165) ; 

 Salisbury (L:B.M.165); Brentwood, Essex (L:B.M.165) ; Boynton, 

 Yorkshire (B.M. 1160) ; Tregayan, Anglesey (B.M.) ; France (B.M. 

 1161) ; Germany (B. M. 653) ; Finland (B. M. 767) ; Sweden (K. 1702) ; 

 Tasmania (K. 1710); Philadelphia (L:B.M.165) ; Ohio (L:B.M.165) ; 

 Florida (B. M. 987). 



4. P. variabilis Rost., Mon., p. 295 (1875). Plasmodium ? 

 Sporangia sessile, globose on a narrow base, 0'5 rnm. diani., 

 or forming curved or net-like plasmodiocarps, scattered, ochrace- 

 ous-yellow or pale umber ; sporangium-wall of two layers, the 

 outer charged with dark angular granules, closely combined 

 with the membranous papillose inner layer ; in some cases the 

 outer layer is not distinguishable in the upper part of the 

 sporangium. Capillitium a profuse network of sparingly branched, 

 yellow threads, 2 to 4 ^diam., rough with minute scattered warts 

 and irregular constrictions. Spores yellow, minutely warted, 

 10 to 15/xdiam. Physa/rwm vermicular e Schwein., in Trans. Am. 

 Phil. Soc., N. Ser., iv., p. 257 (1834). Ophiotheca vermicidaris 

 Mass., Mon., p. 134. Perichcena vermicularis Host., Mon., App., 

 p. 34 (1876); Lister, in Jour. Bot. (1891), p. 265. Perichcena 

 Friesiana Rost., Mon., p. 296. Ophiotheca umbrina Berk. & 

 Curt., in Grev., ii., p. 68. Licea reticulata Berk. & Br., in Journ. 

 Linn. Soc., xiv., p. 86. Perichcena reticulata Rost., Mon., App., 

 p. 35. Ophiotheca reticulata Mass., Mon., p. 133. Perichcena 

 confusa Mass., Mon., p. 117. 



Plate LXX1L, B. a. sporangia, x 20 ; ~b. portion of papillose wall of 

 the upper part of the sporangium, x 280 ; c. capillitium and spores, 

 x 280 ; d. capillitium and spore, x 600 (England). 



The yellow form of this species has appeared in some abundance 

 in successive years at Lyme Regis, and corresponds exactly with the 

 type specimen of Physarum vermiculare from Schweinitz (K. 1671). 

 The German type of P. variabilis is not represented in the Strassburg 

 or British collections, but examination of the type of Ophiotheca 

 umbrina from Curtis (K. 1705), which is given as a synonym for 

 P. variabilis by Rostanuski (Mon., App., p. 35) shows that it is a 

 pale umber, plasmodiocarp form, agreeing in the structure of the 

 sporangium- wall, capillitium, and spores with the English gatherings. 

 P. Friesiana Rost. is described as differing from P. variabilis in the 



