comatrichaJ stemonitaceae 151 



Genus 19.— COMATRICHA Preuss in Linnaea, xxiv. 140 

 (1851). Sporangia cylindrical, ovoid or globose, gregarious or 

 scattered ; sporangium-wall evanescent (subpersistent in C. 

 typhoides), stalked, the black solid stalk extending within the 

 sporangium as a columella for half its length or more, branching 

 above, and continued into the capillitium, which consists 

 of numerous threads combined into a more or less uniform 

 network, not uniting to form an even superficial net. 



The genus Cotnatricha is a somewhat artificial one, for it includes 

 species which agree with Lamproderma in all characters but the per- 

 sistent sporangium-wall, and with Stemonitis in all but the presence of 

 the superficial net of the capillitium, while in C. typhoides a surface 

 net is often developed on the lower half of the sporangium ; at the 

 same time it is a useful genus, typically marked by the uniform net- 

 work of the capillitium and by the isolated not fasciculate growth 

 of the sporangia. 



KEY TO THE SPECIES OF COMATRICHA. 



A. Spores rather dark brownish- violet or grey : — 



a. Spores nearly smooth — 



Capillitium dense, crisped or flexuose, usually arising 

 from the whole length of the columella ; spores brown 

 in mass, 7 to 10 p. diam. ; on wood. 1. C. nigra 



Resembling C. nigra, but spores black in mass, 10 to 

 11 p diam. 2. C. Suksdorjii 



Capillitium with primary branches stout and nearly 

 straight, arising from the whole length of the columella ; 

 on wood. 3. C. laxa 



Capillitium dense, arising by a few branches only from 

 the apex of the columella. 4. C. elegans 



b. Spores spinulose or reticulated — 



a. Sporangia globose ; columella ending in strong 

 branches continued into the flexuose network of the 

 capillitium ; spores warted ; on leaves. 5. C. lurida 



b. Sporangia long, slender, cylindrical — 



Spores closely reticulated. 9. C. longa 



Spores spinulose. 10. C. irregularis 



B. Spores pale ; lilac or reddish lilac : — 



a. Spores marked with a few widely scattered warts, 

 otherwise smooth, or (in var. heterospora) delicateij^ 

 reticulated, 4 to 6 p diam. ; on wood (var. microspora 

 on leaves). 8. C. typhoides 



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