W. C. StHvgis — Type-Spechnens of Myxomycetes. 487 



its capillitium it presents even a more marked divergence toward the 

 genus Trichia than does the specimen with which it is associated. 



The spores of the Granville specimen are slightly smaller than those 

 of either 0. nitens or the type-specimen of O.flavldion;* this, however, 

 is a slight and uniraporiant distinction. A most careful examination 

 of these specimens and a comparison of them with many specimens 

 oiO. W27e?i5, leads to the conclusion that the name Oligonema flavidum 

 is worthy of retention as applied to specimens showing more or less 

 the habit of the genus Trichia and provided with densely and very 

 minutely spinulose elaters, although specimens may occur which, in 

 the abundance of the capillitium and the indications of spirals on the 

 elaters, are hardly distinguishable from members of the genus 

 Trichia, while others may show an equally marked divergence 

 toward Oligonema nitens. 



Oligonema brevifila, Pk., Rep. XXXI, p. 42, 1889. In outward 

 appearance the type-specimen of this species is almost indistinguish- 

 able from 0. flavidum, Pk. The color of the sporangia is of a 

 slightly browner tinge and the wall is of a duller lustre. Macbride 

 founds a specific distinction between them on the ground that O. 

 brevifila occurs "in broad effused patches" and 0. flavidum "in 

 small heaped clusters." This distinction is not apparent in the type- 

 specimens, both being equally effused, with the latter, if anything, 

 less heaped together than the foi'mer. Both occur on moss. The 

 sporangium-wall of 0. breviflla shows the inner surface marked with 

 densely clustered, very minute, bristle-like, appressed hairs, as in 0. 

 flavidum. The spores of 0. breviflla are slightly smaller (11.2-r2ju,) 

 than those of O. flavidum. The only marked difference between the 

 two is seen in the elaters. In 0. breviflla they are extremely scanty, 

 reduced in length and increased in thickness ; in shape they are ii-reg- 

 ularly cylindrical or fusiform ; they are marked with fairly distinct 

 but crowded and irregular spiral bands, occasional short, blunt spines 

 or warts, and minute scattered spinules. (PI. LXI, fig. 25.) This rudi- 

 mentary condition of the elaters is 'practically the only feature which 

 distinguishes this form from the Granville specimen of O. flavidum 

 above described. The length of the elaters surely affords very insuffi- 

 cient grounds for establishing specific distinctions either in this genus 

 or in the genus Trichia, since, e. g., typical specimens of Oligonema 

 nitens almost always show, among the normal, long elaters, a few 



* The following are the spore-measurements of these three forms : O. flavidum, 

 13-15/ii ; O. nitens. 12-14. 2/z ; the Granville specimen, 10.5-13.7//. In all other 

 respects the spores are identical. 



