OLIGONEMA 279 



and imperfect, scattered rings or mere roughenings, sometimes im- 

 perfect or faint spirals; spores yellow. 



The oligonemas are simply degenerate Trichiae, and show the 

 vagaries usually to be noted in a passing type. They are difficult to 

 define, and the species are indeed variable. Those here listed seem to 

 offer constant features throughout our range. 



Key to Species of Oligonema 



A. Spores reticulate. 



a. Sporangia in broad effused patches . . 2. O. bre'vifilutn 



b. Sporangia in small heaped clusters. 



i. Elaters roughened, no distinct rings or spirals, 



1. O. fiavidum 

 ii. Elaters with scattered rings; sometimes faint spirals, 



3. O. nitens 



B. Spores warted 4. O. fulvum 



1. Oligonema flavidum {Peck) Mass. 



1874. Perichaena flavida Peck, Rep. N. Y. Mus., p. 76. 

 1892. Oligonema flavidum (Peck) Mass., Mon., p. 171. 



Sporangia crowded and superimposed, sessile in small masses or 

 clusters 1 cm. or less, bright yellow, shining, the peridium thin but 

 opaque, yellow; capillitium of long, slender tubules usually simple, 

 anon branched, even, or with an occasional inflation, the sculpture 

 confined to warts or small, distinct spinules, roughening more or less 

 conspicuously the entire surface, the apices generally obtuse, anon 

 apiculate; spore-mass yellow, spores under the lens pale yellow, irreg- 

 ularly globose, beautifully reticulate, the meshes large and few, as 

 in Trichia favogineUj 12—14 n. 



This species is marked by its capillitium, which is abundant for the 

 present genus. The threads are longer than in any other species, and 

 not infrequently branched, smooth, or more commonly, very distinctly 

 minutely spinulose throughout, no trace of rings or relief sculpture of 

 any sort, the spirals, that are to be expected, very imperfect, if dis- 

 cernible at all. In habit the species resembles O. nitens, but the col- 

 onies are much larger, and the sporangia higher and larger, attain- 

 ing 1 mm. 



New England to Iowa and Nebraska; south to Alabama and 

 Louisiana. Toronto; Miss Currie. 



