COMATRICHA.] STEMONITACEJ!. 121 



2'3 mm. long, 0-5 mm. broad. Stalk black, often clothed with 

 the grey membranous continuation of the sporangium-wall ; 

 0-5 to 1-3 mm. long, 0'06 mm. thick, rising from a well-developed 

 hypothallus. Columella reaching nearly to the summit of the 

 sporangium, branching at the apex. CapilHtium a close network 

 of flexuose, pale-brown threads, springing from all parts of the 

 columella, the ultimate branches more slender, free, or continuous 

 and looped in the lo.wer half, resembling the superficial net of 

 Stemonitis. Spores pale lilac- brown, marked with 3 to 5 dark, 

 flattened warts on the hemisphere; otherwise almost smooth, 

 minutely warted or faintly reticulated, 3-5 to 7 fj. diam. — Trichia 

 typhoides'BvXi., Champ., p. 119 (1891). Stemonitis typhoides DC, 

 Fl. Franc, ii., p. 257. Stemonitis typhina Wiggers, Prim. Fl. Hols., 

 p. 110 (1780) ; Pers., Obs., i., 57 ; Mass., Mon., p. 74. Gomatricha 

 typhina Eost., Mon., p. 197 (1875) ; Cooke, Myx. Brit., p. 47^ G. 

 affinis Rost., Mon., p. 202. Stemonitis affinis Mass., Mon., p. 76. 

 <S^. atra Mass., Mon., p. 78. S. Garlylei Mass., Mon., p. 84. 



a. genuina : sporangium-wall subpersistent ; spores 6 to 7 /x 

 diam., surface almost smooth, or minutely warted between the 

 larger warts. 



p. heterospora Eex, in Proc. Acad. Nat. Sc. Phil., 1893, p. 367 : 

 sporangium- wall evanescent ; spores 5 to 6 /x diam. ; surface 

 marked with faint, broken reticulation between the warts. 



y. microspora : sporangium-wall evanescent; spores 3'5.to 

 4'5 /x diam., sculpture of spores as in /3. 



Plate XL VI., A. — a. sporangia, u.. genuma, x 3i ; J, o. dense and lax 

 forms of capillitium, x 180 ; d, e. spores of the same, showing widely 

 scattered warts, x 600 (England) ; /. sporangia, j3. heterospora, x SJ ; 

 g. spore, faintly reticulated between the warts, x 600 (U.S.A.) ; h. sporangia, 

 y. microspora, x 3i ; i. capillitium, x 180; J. spore, x 600 (England); 

 7i. spore of Stemonitis Virginiensis Rex, x 600 (U.S.A.). 



Plate XLVI., B. — a. sporangia intermediate between a and |8, x 3^ ; b. 

 capillitium, x 180; c. spore, minutely warted between the large scattered 

 warts, X 600 (Iowa). 



The capillitium varies in the closeness of the network ; forms occur 

 in which the threads are less flexuose, and bear nearly the same 

 relation to the type as C. laxa to C. obtusata. The scattered warts on 

 the spores, the existence of which was first pointed out by Dr. Rex, 

 is a character which, although requiring a high magnifying power to 

 identify, is present in all the varieties given above, and is additional 

 evidence that they all belong to a single species, y. microspora 

 is represented by a gathering in perfect development from Lyme 

 Regis ; in form and colour it resembles ^, but the spores are uni- 

 formly minute. A specimen received from Mr. Morgan, Ohio, is 

 almost identical, with spores of the same size. Specimens of C. 

 typhoides, a., have been received from Prof. Macbride, Iowa, under the 

 name of C. pulchella (B. M. 1007) ; the sporangia are cylindrical, and 

 the spores, which measure 6 to 7 /u, are marked with minute warts, 

 and a few inconspicuous larger warts. This form is connected with 

 the more usual type by other specimens from Iowa with minutely 

 warted spores in which the few larger warts are well developed 

 (L:B.M.91 ; Plate XLVI., B., a. to c). The type of C. affinis Rost., 



