Pl.cell.aph. 1. HYDROPHYTE. 2. Oscillat. 281 
2. Oscillatoria nigra. Black quick-moss. 
Bed black, slippery; threads radiating, very long, stiff, 
straight, grayish yellow. 
Oscillatoria nigra, Vauch. 192. 
Conferva fontinalis, Dillwyn, 64, fig. and partly the description. 
Bottom of running waters; becoming free in the spring. 
Threads entangled; radii about an inch long, blunt, 
oscillating very lively; rzgs rather distant. 
3. Oscillatoria tenuis. Slender quick-moss. 
Bed green, slippery; threads radiating, short, rather 
stiff, straight, light green. 
Conferva gelatinosa, omnium tenerrima et minima, aquarum limo in- 
nascens, Dillen in Raii Syn. 417. 
Oscillatoria viridis, Vaucher 195. 
Conferva fontinalis, Roth Catal. 3, 195. 
Conferva limosa, Dilhoyn Syn. 30; Engl. Bot. 2058. 
Oscillatoria tenuis, Agardh Decad. 2, 17. 
Still waters on mud; Summer. 
Threads half an inch long, very slender; rigs very close. 
4. Oscillatoria tenuissima. Very-slender quick-moss. 
Bed velvetty, shaggy, dark green; threads crowded in 
ascending tufts, straight, rather stiff, pellucid, very slender. 
Conferva tenuissima, Engl. Bot. 2584, 
Oscillatoria tenuissima, Agardh Disp. ed. 2,33. 
‘Warm springs, as at Bath. ' 
Beds very irregular; threads about one-hundredth of an 
inch in diameter. 
f 
4 
5. Oscillatoria ? ochracea. Ochry quick-moss. 
Bed thick, ochre brown, brittle; threads very slender, 
yellowish green, incumbent. 
Conferva ochracea, Roth Cat. 1,165; Dillw. 162. 
Oscillatoria ochracea, Lyngbye Hydr. D. 89- 
In chalybeate springs. 
Bed thick, slippery, drying to an ochry powder ; threads 
slightly bent: rings very close, intermixed with distant 
ones. ' 
Ill. 3. HUMIDA. Humida. 
Threads simple, membranaceous, bent, entangled, de- 
cumbent, free, not oscillating, nor lengthening.—Damp,. 
shady places. 
