lamproderma] stemonitaceae 165 



shining like burnished brass ; sporangium- wall membranous, 

 persistent, purplish hi the lower part, usually mottled with 

 darker shades. Stalk cylindrical, usually 1-5 mm. high, 0*15 

 mm. thick, purplish-black, shining, longitudinally striate or 

 rugose, rising from a dark purplish hypothallus. Columella 

 cylindrical with a conical apex, or clavate, reaching to more than 

 half the height of the sporangium. Capillitium of brownish- 

 purple threads, radiating from the columella, sparingly forked 

 and anastomosing, towards the surface branching and form- 

 ing a delicate, nearly colourless network. Spores purple- 

 grey, closely spinulose, 11 to 14 ^ diam. — Rost. Mon., p. 203 ; 

 Mass. Mon., 100 ; Macbr. N. Am. Slime-Moulds, 141. Physarum 

 columbinum Pers. Obs. Myc, i. 5 (1796) ; Fr. Syst. Myc, 

 iii. 136 (1829). P. salicinum Schum. Enuni. PI. Saell., ii. 200 

 (1803) ? P. bryophilum~Fr. I.e., 135 ? Stemonitis physaroides 

 Alb. & Schw. Consp. Fung., 103, t. 11, fig. 8 (1805) ? S. por- 

 phyra Berk. & Curt, in Grev., ii. 69 (1873) ? Lamproderma 

 physaroides Rost. Mon., p. 202 ; Mass. I.e., 103 ; Lister Myce- 

 tozoa, 125 ; Macbr. I.e., 139. L. Schimperi Rost. I.e., p. 203. 

 L. Staszycii Racib. hi Hedw., xxviii. 116 (1889). 



Var. sessile Lister : sporangia sessile, without columella, 

 capillitium dark or pale. — Physarum iridescens Berk, in Hook. 

 Journ. Bot., iii. 20 (1851). Lamproderma iridescens Rost. Mon., 

 App. p. 25 (1876). 



PI. 131. — a. sporangia (England) ; b. c. sporangia (Switzerland) ; d. ellipsoid 

 sporangia (South America) ; e. f. capillitium and columella ; g. capillitium from 

 lower part of sporangium ; h. sporangia of var. sessile (England) ; i. capillitium 

 of same ; k. columellae of various shapes from one group of sporangia ; I. m. spores. 



This beautiful and widely distributed species is subject to considerable 

 variation in the shape of both the sporangium and columella and in the 

 length of the stalk. Spherical forms with shorter stalks some- 

 times occur closely resembling L. violaceum var. Sauteri, from 

 which they may be distinguished by the capillitium threads being 

 less intricately branched and purple in colour with hyaline tips, 

 and by the purplish-grey spores. The tj^pe of Stemonitis iridescens 

 Berk, on Hepatics from the Pyrenees (K. 1318), is the var. sessile of 

 the present species; the sporangia, now broken, were globose, and 

 either sessile or on short stalks ; the capillitium is described by Rosta- 

 finski as colourless, though in a sporangium examined the few threads 

 that remain are dark brown ; the columella is absent, but the base of 

 the sporangium is thickened by a tissue of purplish-brown interwoven 

 bands ; the spores are purple-grey as in the type. Another gathering of 

 var. sessile from Norway, kindly furnished by Prof. Blytt, is on moss 

 associated with the long stalked form of L. columbinum ; the globose 

 sporangia are each seated on a yellowish horny cushion of dried Plas- 

 modium ; there is no stalk or columella ; the capillitium rises from 

 the broad base of the sporangium and is more rigid than that of the 

 stalked form ; the spores measure 16 to 19 fi ; in the accompanying 

 stalked sporangia they measure 12 to 13 /a. It would seem probable 

 that some gatherings at least of the var. sessile are not normal develop- 

 ments. Typical L. columbinum has occurred abundantly every autumn 

 for some years in succession on moss on wet rocks in a wooded ravine 



