172 THE MYXOMYCETES 



m. Robust, truncate, 2-6 mm. tall; stem equal to sporangium 



or shorter 11. C. suksdorfii 



m. Cylindrical or slightly ovate, 7-8 mm. tall; stipe at least 



half the total height 12. C. pacifica 



n. Spores reticulate 13. C. reticulata 



n. Spores warted to nearly smooth o 



o. Capillitium caducous except at top ; spores usually under 6 n 14. C. fragilis 



o. Capillitium persistent; spores usually larger p 



p. Sporangia distinctly cylindrical q 



p. Sporangia globose to ovoid, rarely short cylindrical r 



q. Stipe long, equal to sporangium; spores 7.5-8 fi 15. C. cequalis 



q. Stipe short; spores 9-10 p. 16. C. subcoespitosa 



r. Usually 2-4 mm. tall 17. C. nigra 



r. Under 2 mm. tall •s 



s. Columella nearly reaching apex 18. C. ellisii 



s. Columella shorter t 



t. Columella reaching middle of sporangium; spores 



coarsely warted 19. C. lurida 



t. Columella divided at base into several main branches; 



spores finely spinulose 20. C. elegans 



u. Cylindrical; spores with sparsely scattered clusters of warts 21. C. typhoides 



u. Spores more densely and uniformly spinulose v 



v. Base of peridium persisting as a cup; globose or elliptical 22. C. rubens 

 v. Base of peridium not persistent; ovate to short cylin- 

 drical w 



w. Capillitium pallid or flesh colored 23. C. lenerrima 



w. Capillitium dark 24. C. pulchella 



1. COMATRICHA C^SPITOSA StUTgis 



Bot. Gazette 18 : 186. 1893. 

 PI. XII, Figs. 278, 279. 



1907. Diachcea ccespitosa (Sturgis) List., Jour. Bot. 45 : 186. 



Sporangia densely crowded or caespitose, sessile or short-stipitate, 

 clavate, 1-1.5 mm. high; peridium gray, iridescent with blue tints, 

 comparatively permanent but finally disappearing; columella attain- 

 ing two-thirds to three-fourths the height of the sporangium, giving 

 rise throughout its length to the dense blackish capillitium; hypo- 

 thallus delicate, inconspicuous; capillitium, the main branches thick at 

 the point of origin, frequently anastomosing, and becoming gradually 

 thinner toward the surface of the sporangium, the tips pointed, free, 

 forming the network; spores blackish violet in mass, by transmitted 

 light pale brownish violet, irregularly verrucose, 10-13 ;u. 



A very distinct and curious species. The sporangia are densely 

 crowded, though by the nature of habitat somewhat tufted. The 

 shape of the individual sporangium is quite uniformly clavate or 



