274 NEMATOGEN.E. 
GENUS 112. HAPALOSIPHON. Noy. (1849-) 
Trichomes formed mostly of a single row of cells, sheath 
slender. Aquatic plants, looking like Tolypothrizx. 
Hapalosiphon byssoideus. Kirch. Alg. Schl., 231. 
Tufts compact, dark olive, trichomes ascending, rigid, oliva- 
ceous, sparsely branched, containing cells arranged in a single 
series. Cells at first rounded quadrate, equal in length and 
breadth, becoming when older divided and shorter, one-third or 
one-fourth the length of their diameter ; sheath very thick, 
distinctly lamellose, golden yellow, attenuated and obtuse at the 
apex. 
MBER, Trichomes ‘025--03 mm. diam. Cells ‘012 x -01 
mm. 
Strosiphon truncicola, Rabh. Alg. Eur. ii., 286. Hedwigia 
i, p. 47, t. ix., f. 3. 
Hassallia byssoidea, Hass. Alg. 282, t. 67, f. 5. 
Scytonema byssoideum, Harv. Eng. Fl. v., 366. Berk. Glean., 
t. 19, f. 1. Harv. Man. 156. 
On trunks of beech, &c. 
Plate CXI. fig. 5. Portions of trichomes X 400 diam. 
SPECIES FOR ENQUIRY. 
Dasygloia amorpha. TZhuwaites. 
Gelatinous, amorphous, sheaths of the trichomes thick, muci- 
laginous, cohering, slightly branched ; internal trichomes blue- 
green, slender, simple, septate. 
Size. Not indicated. 
Dasygloia amorpha, Thwaites in Eng. Bot. ii. Supp., t. 
2941. 
In bogs. 
Coalescing in a solid gelatinous mass, as large as a swan’s egy. The 
filaments, quite at the base of the plant, have rather « membranous 
than gelatinous sheath, and closely resemble those of a Lyngbya, in 
consequence of which the base of the mass is green, but in the centre of 
the plant each filament is furnished with a very thick colourless gela- 
tinous sheath, which is firmly coherent with those in contact with it. 
Towards the periphery of the plant these sheaths assume a brown 
colour, and become somewhat separate and distinct, rendering the sur- 
face shaggy. Occasionally the tips of the filaments are wound spirally 
round the portion beneath them. 
Plate CXII. fig.1. 4, portion of gelatinous mass, natural size; 4, 
threads, with gelatinous sheaths, magnified ; ¢, portion of trichome, with- 
out sheath, further magnified—all after Thwaites. 
