arcyria] arcyriaceae 237 



In this species the shape of the sporangium is very variable. An 

 extensive growth of the common grey form arising from one develop- 

 ment of Plasmodium will often exhibit much diversity ; subglobose 

 sporangia with short stalks and subcylindrical sporangia with long 

 stalks are found in company with the more usual ovoid form, and are 

 either single, or are combined in clusters of two to five, when they 

 correspond with the form named A. digitata Rost. Groups are met with 

 on dead bramble stems and holly leaves in which the nearly white 

 scattered or clustered sporangia are shortly stalked and perfectly 

 globose, 0-5 to - 7 mm. diam. ; these are associated with other 

 groups of sporangia varying in shape from subglobose to ovoid. 

 Specimens from North and South America and from the tropics are 

 usually elongated or cylindrical. The markings on the capillitium 

 vary also. In some gatherings of the grey form the threads are 

 slender and of nearly uniform thickness throughout, and are 

 either spinulose, with the spines minute and equally distributed, 

 or are marked with a band of larger spines 1 to 3 ju. long, either sharp - 

 pointed or thickened at the apices, arranged in a loose spiral ; in 

 other gatherings, especially in cold weather developments, the 

 threads are broad, 5 fx diam., and papillose all over. The type 

 specimen of A. Friesii Berk. & Br. from Glamis, N.B. (K. 896), 

 is a bluish-grey ovoid form of the present species, with typical 

 capillitium and spores. A. digitata Rost. is the cylindrical form of A. 

 cinerea, with sporangia mostly in clusters of three to seven together ; 

 the stalks usually equal the sporangia in length, and, though adhering, 

 are easily separable ; the " botrytis " arrangement cannot be viewed 

 as having any specifio value. The type of A. Cookei Mass., from 

 Brazil (K. 865), is a tall grey form of A. cinerea ; the sporangia 

 measure 2 mm. in length, 0*5 mm. in breadth ; the stalks are 2 mm. 

 long, 0- 1 mm. thick ; the capillitium and spores are quite typical. 

 The var. carnea, with flesh-coloured sporangia and compact 

 capillitium somewhat resembles pale forms of A. stipata, but shows 

 no trace of spiral markings on the threads. 



Hob. On dead wood, twigs, and more rarely on leaves. Common. — 

 Batheaston, Somerset (B.M. 276) ; Char ton, Devon (B.M. 1497) ; 

 Luton Hoo, Beds (B.M. 1498) ; Bromsgrove, Worcester (B.M. 1500) ; 

 Sibbertoft, Norths (K. 896) ; Chatsworth, Derby (B.M. 3027) ; North 

 Wales (B.M. 3028) ; Aberdeen (B.M. 3029) ; Ireland (B.M. 3030) ; 

 France (K. 859) ; Germany (B.M. 713) ; Poland (Strassb. Herb.) ; 

 Austria (B.M. 1836); Switzerland (B.M. 3031); Italy (B.M. 1973); 

 Portugal (B.M. 3032) ; Cape (K. 858) ; Ceylon (B.M. 3033) ; Java 

 (B.M. 3034) ; Borneo (B.M. slide) ; Australia (B.M. 714) ; New Zealand 

 (B.M. 3035) ; Tonga Tabu (B.M. 3036) ; Japan (B.M. 2021) ; Montreal, 

 Canada (B.M. 3037) ; Iowa (B.M. 828) ; Philadelphia (B.M. 1851) ; 

 South Carolina (B.M. 972) ; Nicaragua (B.M. 1030) ; Dominica (B.M. 

 1757) ; Brazil (B.M. 3038) : var. carnea — Bohemia (B.M. 3039) ; 

 Holstein (B.M. 3040). 



4. A. pomiformis Rost. Mon., p. 271 (1875). Plasmodium 

 white. Sporangia scattered, stalked, subglobose or ovoid, 

 0-3 to 0-7 mm. diam., ochraceous-yellow ; cup of sporangium- 

 wall plaited at the base, nearly smooth, faintly reticulated or 

 papillose. Stalk slender, buff, 02 to 0-4 mm. high, filled with 

 spore-like cells. Capillitium a loose elastic network of yellowish 



