HEMITRICHIA.] TRICHIACE^J. 175 



KEY TO THE SPECIES OF HEMITRICHIA. 



A. Spores nearly smooth, or minutely warted : 



A. Capillitium red, spinose. 1. H. rubiformis 



B. Capillitium yellow or yellow-brown 



a. Sporangia stalked 



Stalk solid. 2. H. intorta 



Stalk hollow, filled with spore-like cells 



Cup papillose. 3. H. clavata 



Cup smooth. 4. H. leiocarpa 



b. Sporangia sessile 



Spirals of Capillitium one to three, prominent, 

 sporangium-wall membranous. 



5. H. Wigandii 



Spirals of Capillitium three or more ; indistinct, 

 sporangium-wall thickened with granular 

 deposits. 6. H. Karstenii 



B. Spores reticulated : 



Capillitium threads spinose. 7. H. Serpula 



Capillitium threads smooth. 8. H. clirysospora 



1. H.i rubiformis Lister. Plasmodium purple-red, in rotten 

 wood. Total height l - 3 to 2'5 mm. Sporangia clavate or sub- 

 cylindrical, stipitate or sessile, combined in clusters or crowded, 

 1 to 1'3 mm. high, O5 to O7 mm. broad, glossy or shining, dark 

 red, red-brown, or olive-black ; sporangium-wall of two layers, the 

 outer continued into the stalk, the inner enclosing the spores, 

 orange-red. Stalks membranous, - 2 to 1 mm. high, usually 

 combined in clusters of from six to twelve, furrowed and rugose, 

 red, not enclosing spore-like cells. Capillitium of twisting, spar- 

 ingly branched, orange-red threads 5 to 6 /x diam., marked with 

 three to five regular spiral bands, beset with numerous scattered 

 spines 2 to 5 /JL long, rarely nearly smooth, with few pointed free ends. 

 Spores pale orange-red, warted, 10 to 11 //, diam. Hemiarcyria 

 rubiformis Host., Mon., p. 262 ; Cooke, Myx. Brit., p. 67, figs. 201, 

 230, 231 ; Blytt, Bidr. K. Norg., Sop. iii. (1892), p. 13 ; Mac-bride, 

 in Bull. Nat. Hist. Iowa, ii., p. 133. Trichia rubiformis Pers., 

 in Homer, N. Mag. Bot., i., p. 88 (1794). Arcyria rubiformis 

 Mass., Mon., p. 158. Trichia Neesiana Cor da, Ic., i., p. 23. 



a. genuina : sporangia red-brown. 



/?. Neesiana Eost. : sporangia olive black. 



Plate LXIIL, A. a. sporangia, x 20; b. Capillitium and spores, * 280; 

 c. capillitium and spore, x 600 (England). 



Sporangia are occasionally found with a few free elaters pointed 

 at each end, in addition to the continuous network of threads of the 

 usual type. 



