232. 3. Humida. 1, HYDROPHYTZ. Pl. cell. aph. 
1. Humida muralis. Wall humida. 
Threads green, rather stiff, bent, twining, rather thick, 
entangled so as to form a close green matt. . 
Conferva muralis, Roth Cat. 3,187; Dillw. 7; Engl. Bot. 1554. 
Conferva rigida, Roth. Cat. 1, 165. 
Oscillatoria parietina, Vauch. 195, 
Oscillatoria muralis, Agardh Disp. 1, 27. 
Garden-walls, damp areas; all winter. 
2. Humida decorticans. Slip-coat humida. 
Threads very slender, bluish green, bent, entangled into 
a very close green mat. | 
Conferva muscosa confragosa rivulis innascens, Dilien. Musc. 15. 
Conferva confragosa, Lightf. Scot. 976. 
Conferva violacea, Wudsun Fl. Angl. 592. 
Conferva decorticans, Dillwyn, £6. 
Oscillatoria decorticans, Lyngbye Hydr. Dan. 95. 
Damp woods and bark of trees; summer. 
Threads three times as slender as those of humida muralis. 
3. Humida cyanea. Sky-blue humida. 
Threads very slender, glaucous blue, covered with a de- 
ciduous coat, entangled into a close sky-blue mat. 
Conferva cyanea, Engl. Bot. 2578. 
Oscillatoria cyanea, Agardh Disp. ed, 2, 33. 
Damp walls and stones, 
IV. 4. ELISA. Elisa. 
Threads simple, rarely adhering to one another, as if 
branched, membranaceous, gelatinous, upright, tufted, free, 
not oscillating, ner lengthening. 
1. Elisa fontinalis. Spring elisa. 
Fresh water; threads simple, very slender, nearly hyaline, 
rather stiff, upright, short, forming a dark green mat. 
Conferva fontinalis fusca omnium minima mollis, Dillen in Raii Syn, 58. 
Conferva fontinalis, Fl. Dan. 651; Engl. Bot, 2054. 
Oscillatoria fontinalis, Agardh Syn, 110. 
Stones and posts in water ; stimmer. 
Tufts very small, dark or light-green; threads aggre- 
gated, a quarter of an inch long, straight; adheres to paper. 
2. Elisa bicolor. Two-coloured elisa. 
Fresh water; threads simple, slender, bright green, 
weak, very long, forming a bright green fluctuating mat. 
Conferva bicolor, Exgl. But. 2288. 
