404 
cell rounded or pointed, no calyptra; 
cells 4-6 mic. long; transverse walls with 
fine granules. In a stream of warm water 
near a hot spring. (G., 234, 7, 22-23; T., 
83, 4, 37-38.) 
57. LIrichomes 4-4-5 mic. in diameter 
61. 
Stratum membranaceous, dull 
lead-coloured ; trichomes 
green or 
straight, 
tangled ; cells shorter than the diameter, 
transverse walls granular; cell 
violet or sky-blue; apical cell drawn out 
contents 
to a point, conical. In fresh water, in 
greenhouses. (T., 79, 4, 31.) 
58. Plants in hot, brackish or salt water 
58. Plants in fresh water 
Stratum lamellose, yellowish-green ; 
trichomes 2-2-8 mic. in diameter, 
straight, 
constricted at joints; cells 6-8 mic. long ; 
apex tapering, bent or twisted, not capi- 
tate; apical cell more or less acute, no 
Calyptral (G60) 4 2657 S90; 45567.) 
59. Stratum mucous, ieee yellowish or dark blue- 
green 
Trichomes | “12-23 mic. in diameter, 
more or less flexuous, constricted at 
joints; cells 1-2-3mic. long 
pa apex 
tapering; apical cell acute conical, no 
calyptra. In hot or brackish water. (G., 
163,54; 3th ie =, Osea 53.) 
59. Stratum delicate, rose-coloured, velvety 
Sheaths diffluent ; filaments — 
entangled ; trichomes 1-7-2 mic. 
loosely 
in dia- 
meter, much constricted at joints; cells 
2-7 mic. long; apex tapering; apical cell 
acute conical, no calyptra. In 
salt or 
brackish water, forming a delicate film 
on shells, roots, etc. (G., 164; 
Tt 04.) 
60. Apex of trichome especially capitate, transverse 
walls with well-marked double 
granules 
rows of 
Stratum thick or papery, frequently 
forming a layer on wood and stones in 
streams: trichomes 4°5-9 mic. 
in dia- 
meter, more or less flexuous, not con- 
stricted at joints; cells 3-7 mic. long; 
sheaths usually not present; apex gradu- 
ally tapering, calyptra obtuse. On wood 
in water troughs, under. mill-wheels, etc. 
(G,, B80, 15; 4p ye cL, 10455, 
Q-I0). 
60. Apex of trichome slightly capitate, transverse 
walls not granular . 
Stratum thin, membranaceous, dark 
green ; trichomes 6-8 mic. in diameter, 
straight, not constricted ; apex tapering, 
straight ; cells of trichome 3-8 mic. long ; 
sheaths absent; calyptra conical de- 
pressed. In warm or fresh water; on 
rocks, “(Ga woop aloe (il | Geos esr) 
In salt water 
Stratum dull green ; trichomes elongate, 
Notes on the Blue-green Alge, etc. 
O. violacea 
. -- 59 
P. subuliforme 
P. fragile 
P. persicinum 
P. favosum 
P. calidum 
O. subliformis 
Naturalist, 
