LYNGBY. 255 
* Trichomes enclosed in a transparent sheath from which they emerge to 
reproduce new filaments, sheath containing several trichomes.  Fila- 
ments growing in scattered creeping erect or floating wick-like bundles,”— 
Thuret. . 
Hydrocoleum thermale Kutz., mentioned in Quart. Journ. Micr. Sci. 
(1867) p. 86, as having occurred in Ireland, we have never seen, and, 
therefore, do not know whether it should be included in Microcoleus. 
Microcoleus gracilis. Hass. Alg. 261, t. 70, f. 2. 
Effused broadly in a thin dark green stratum. Trichomes 
pale blue green, slightly curved, in fascicles densely contorted 
abont the apex, joints 2-3 times longer than their diameter, 
either continuous or distinctly separated, granulated, divisions 
paler, nearly hyaline, a little contracted about the apex, extreme 
apiculus conical, now and then slightly curved, special sheath 
narrow, very delicate, universal sheath very thick lamellose. 
Size. Trichomes ‘0025-003 mm.; fascicles :09-:12 mm. 
Kirch. Alg. Schl. 244. 
Microcoleus marinus, Harv. Man. 168. 
Chthonoblastus salinus, Kutz. Tab. Phye. i, t. 58, f.2. Rabb. 
Alg. Eur. i, 133. 
Oscillatoria chthonoplastes, var. a, Eng. FI. v., 873. Eng, 
Bot. ii., t. 2523. Mack. Hib. 239. 
On salt marshes. 
‘Fronds fixed at the base, floating freely in the water, an inch long, 
tufted, dichotomously branched, branches slender capillary widening up- 
wards, with club-shaped tips; colour olivaceous green or yellowish. 
When ruptured the branches discharge innumerable needle-shaped fila- 
ments, which, when the plant is growing, radiate and oscillate from the 
tips of the branches.”— Harvey. 
Plate XCIX. fig. 1. End of fascicle of trichomes with sheath x 400. 
Microcoleus chthonoplastes. ao in Ann. Sci. Nat. (1875) 
p. 877. 
Stratum thin, or thicker and rather compact, dingy eru- 
ginous green; trichomes slightly flexuous, equal, twisted, in 
dense fascicles, joints nearly twice as long as their diameter, 
rather remote from each other, leaving a hyaline space between 
them, apiculus attenuated, rather elongated; special sheath 
very delicate, universal sheath narrow, scarcely lamellose. 
Size. Trichomes :0035-'004 mm. ; fascicles -03-:035 mm, 
Chthonoblastus Lyngbyet, Kutz. Tab. Phyc. i., t. 58, f. 1. 
Microcoleus anguiformis, Hass. Alg. 261, t. 70, f. 1. Kirch. 
Alg. Schi. 244. 
Chthonoblastus anguiformis, Kutz. Tab. Phyc. i., t.57. Rabh. 
Alg. Eur. ii., 183. Harv. Phyc. Britt. t. 249. 
On the naked ground, by roadsides, &c. 
Plate C. fig. 1. Fascicle of trichomes with sheath x 400. 
