262 NEMATOGENS. 
Lyngbya subfusea. (4g. Syst. p. 64.) 
Substratum velvety, fibrillose, tawny, becoming yellowish, 
forming a firm compact stratum, of a violet or steel blue colour, 
changing to brownish; trichomes rigid, straight, joints about 
half as long as broad, with a double row of points at the com- 
missure, apex rather obtuse, naked. 
Size. Trichomes ‘008 mm. diam. Thinner form, trichomes 
*006--007 mm. diam. 
Phormidium subfuscum, Rabh. Alg. Eur, ii., 125, 
On stones in mountain streams. 
Plate CI. fig. 3. a, portions of trichomes x 400, from Scotch speci- 
mens. 4, portions of trichomes from a thinner form X 400. 
Genus 105. SYMPLOCA. Kutz. (1843.) 
Trichomes articulate, simple, or only exhibiting the beginning 
of ramification, more or less distinctly vaginate, ascending from 
a prostrate base, agglutinated together in erect or anastomos- 
ing fascicles, or wick-like bundles, more or less procumbent, 
coalescing, and often involved in a matrical gelatin. 
Symploca lucifuga, Harv, in Eng. Fl. v., 373. 
Dark eruginous green, fascicles about two lines high, ap- 
proximate, subuliform, apex at length penicillate; trichomes 
single or twin, eruginous, joints equal or a little longer than 
broad, distinctly granulated, sheaths broad, pellucid, colourless, 
quite smooth. 
Size.  Trichomes :0035-:004 mm. diam., including sheath 
‘01 mm. 
Rabh, Alg. Eur. ii., 155. 
Oscillatoria lucifuga, Hass. Alg. t. 65, f. 5,6. Harv. in 
Eng. Fl. v., 373. 
Calothrix lucifuga, Carm. MSS. 
On pastures and heaths, on decayed alder trunk. 
“ Stratum spreading dull blackish green, bristling all over with minute 
erect fascicles about one third of a line high. Filaments thickish, 
flexnous, strongly agglutinated together, annulated within, pale 
yellowish.” — Harvey, 
Plate C1IT. fig. 2. a, portion seen with a pocket lens. 8, trichomes 
x 400. 
