ARCYRIA.] ARCYRIACE^E. 185 



K. JSTorg., Sop. iii. (1892), p. 11 ; Mass., Mon., p. 144. Arcyria 

 intricate*, Rost., Mon., App., p. 37. Arcyria dictyonema Host., 

 Mon., p. 279 ; Cooke, Myx. Brit., fig. 195 ; Mass., Mon., p. 154. 

 Heterotrichia Gabriellce Mass., Mon., p. 140. Arcyria macrospora 

 Peck, in Rep. N. York State Mus., xxxiv., p. 43 (1881) ; Durant, 

 in Bot. Gaz., xix., p. 89. 



Plate LXVL, B. a. sporangia, x 20 ; I. portion of sporangium-wall, 



x 600 ; c, d. threads of upper part of capillitium, x 600 ; e. thread of 



basal part of capillitium, x 600 (England) ; f. capillitium of type of 



A. dictyonema Host, x 600 (Germany) ; g. capillitium of type of Hetero- 



tricliia Gabriellce Mass, x 600 (United States). 



This species varies considerably in the markings on the capillitium ; 

 the network of a single sporangium may in some parts be conspicuously 

 thickened on one side ; in other parts the threads may appear nearly uni- 

 formly spinulose. In the type specime-n of A. dictyonema Rost., from 

 Freiburg, in Strassburg Herbarium, the capillitium is spinose, principally 

 on one side of the thread, with broken reticulation and spinules on the 

 other part ; there are numerous free branches with clavate or pointed 

 ends ; except that the spines are more developed than usual, the markings 

 do not differ from those frequently seen in typical A. ferruginea, of 

 which it must be considered a form. The type specimen of Heterotrichia 

 Gabriellce Mass., from S. Carolina (K. 838), differs from A. ferruginea 

 only in the numerous pointed free ends in the upper part of the net 

 of the capillitium ; the threads are flattened, very closely reticulate 

 and spinulose, and in many places thickened on one side ; the spores 

 measure 10 to 11 /*. The abundance or scarcity of free ends varies 

 much in different gatherings of A. ferruginea, and is not a sufficient 

 character on which to base a species. A. macrospora Peck appears 

 from the description to differ in no respect from typical A. ferruginea. 



Hob. On dead wood. Leytonstone, Essex (L:B.M.153) ; Lyme 

 Regis, Dorset (L:B.M.153) ; Lei^hton, Beds (L:B.M.153) ; Henllys, 

 Anglesey (B. M. 1130) ; France" (K. 921) ; Germany (B. M. 727) ; 

 Norway (Christiania Herb.) ; Australia (K. 848) ; Mass., U.S.A. 

 (L:B.M.153) ; S. Carolina (B. M. 966). 



2. A. versicolor Phillips, in Grev., v., p. 115 (1877). Plas- 

 raodium 1 Total height 2*5 to 3 mm. Sporangia pyriform or 

 clavate, shortly stipitate or sessile, gregarious, 1 to 2 mm. diam., 

 more or less shining, yellow or olivaceous-yellow ; sporangium- wall 

 membranous, persistent except at the apex, yellow, papillose on 

 the inner side. Stalk membranous, 0'2 mm. long, yellow-brown, 

 filled with spore-like cells, arising from a well-developed hypo- 

 thallus. Capillitium an elastic network of freely branching 

 yellow threads, 4 to 6 /x diam., triangular or oval in section, 

 either uniformly spinulose and marked with broken reticulation, 

 or one side thickened and marked with transverse bars ; the 

 threads arise from the tube of the stem, and are not attached to 

 the sporangium -wall ; free ends shortly pointed. Spores yellow, 

 smooth, 8 to 10 /A diam. Mass., Mon., p. 149. Arcyria vitellina 

 Phill., I.e., p. 115. 



Plate LXVIL, A. a. sporangia, x 20 ; 1). portion of sporangium-wall, 

 x 600 ; c. capillitium and spore, x 600 (California). 



