248 NEMATOGENSS. 
Oscillaria rubiginosa. Carmichael Alg. App. ined. 
Stratum gelatinous, dark purple; trichomes very thin, straight, 
indistinctly articulated, laid on a thin, compact, greenish sub- 
stratum. 
Sizg. Threads :004--0045 mm. diam. 
Oscillaria violacea, Rabh. Alg. Eur. ii., 118. Eng. Fl. v. 
377. 
Oseillatoria violacea, Hass. Alg. 254, t. 72, f. 10. Harv. 
Man. 166. Johnst. Fl. Berw. ii., 264. 
Conferva mucosa confragosa rivulis innascens, Dillen (?) 
Rapid streams, and on stones at the bottom of rivers. 
When dry the filaments of this species assume a blackish green cast, 
with an evident gloss. Stria2 when dried almost invisible, at a distance 
of about two diameters from each other.—Hassall. 
As another species is called Oscillaria violacea (Wallr), which has 
priority, the name proposed by Carmichael must be adopted. 
Plate XCVIII. fig. 6. Portions of trichomes X 400, from the original 
specimens. 
Oscillaria subfusca. Vauch. Conf. 193, t. 15, f. 5. 
Forming a very thin, greenish brown, then blackish stratum, 
shortly radiating. Trichomes equal, straight, curved at the 
apex (curvature of 4 to 5 joints), joints about equal in length to 
their breadth (after division shorter), dissepiments very dis- 
tinctly granulate, extreme apical point fimbriate, or bearded. 
Cell-contents pale greenish steel-blue, granular. 
Size. Threads :0045--006 mm. diam. 
Rabh. Alg. Eur. i. 100. Kirch. Alg. Schl. p. 246. Mack. 
Hib. p. 240. Eng. Fl. v., 377. Harv. Man. 166. 
Oscillatoria subfusca, Hass. Alg. 253, t. 72, f. 9. 
Attached to wood, rocks, stones, &c., in streams. 
“Stratum extensive, soft, slimy, void of tenacity, wrinkled, of a 
dusky grey colour, when dry greyish-brown, streaked with green to- 
wards the edges; filaments very slender, striz invisible.”—Harvey. 
Plate XCVI. fig. 7. Portions of trichomes X 400. 
Oscillaxia erugescens. Drumm. Ann. Nat. Hist. (1838) 1, p.1. 
Stratum of a fine deep green, highly gelatinous, when dried 
eruginous blue, and glossy ; trichomes very slender, opaque 
green, conglomerated in large masses, rarely floating, or broken 
into fragments and suspended like cloudy flocculi in the water, 
joints about half their diameter long. 
Size. Trichomes :005 mm. diam. 
Oscillatoria wrugescens, Hass. Alg. 249, t. 72, f. 2. Harv. 
Man. 163. 
