KLEISTOBOLUS 229 



trees kept in a moist chamber for a week or ten days, sometimes grow- 

 ing on the bark directly. 



On lichens, alga? and moss on the bark of trees. Iowa, West Virginia; 

 Europe. 



3. Kleistobolus Lippert 

 Verh. Zool.-Bot. Ges. Wien 44 : 70. 1894. 



Sporangia sessile, minute, opening by a distinct lid, the latter bear- 

 ing globular warts near the margin and short, blunt, finger-like proc- 

 esses at the center; spores pale lilac-brown. 



A single species: 



Kleistobolus pusillus Lippert 



Verh. Zool.-Bot. Ges. Wien 44 : 70. 1894. 



PI. XXI, Figs. 555, 556, 557, 558. 



Sporangia scattered, sessile, operculate, very small, 0.04 to 0.15 mm. 

 in diameter, discoid, rarely subglobose, circular or ellipsoid in outline; 

 peridium simple, membranous, brown, more or less opaque from dark 

 deposits except at the upper margin, which is bordered by a row of 

 tubercles, 1-2 (x in diameter; operculum thin, membranous, pellucid, 

 iridescent, with a convex center bearing on its lower surface blunt, 

 finger-like processes, and a circular margin bearing larger warts or 

 tubercles; spores lilac-brown or pinkish in mass, nearly colorless under 

 the lens, smooth, but more or less coated with granular material, 

 mostly 9-1 1 /x, but varying considerably in size. Plasmodium watery 

 blackish brown. 



This microscopic species was for many years known only from the 

 original Austrian collection, which developed on coniferous wood kept 

 in a moist chamber. More recently it has been found by Jarocki in 

 the mountains of Poland and by him carefully described (1927). His 

 account is in the main confirmed by G. Lister (Jour. Bot. 65 : 202, 

 1927). We have found it in Iowa and are able to account for certain 

 discrepancies between the two accounts. The spores seem always to 

 be smooth, but more or less coated with amorphous granules. They are 

 at first large, 13 /j, or more in diameter, with thin walls and scattered 

 granules. Later they become smaller, the outer walls become thicker 

 and the granules are aggregated as irregular deposits on the surface. 



The sporangia resemble those of Hymenobolina but are smaller 

 and brighter in color, and the warts on the lid are clearly visible under 

 a good lens. The spores, when mature, are smaller and have a lilaceous 

 tinge in marked contrast with the smoky spores of Hymenobolina. 



