26. Stratum thin membranaceous, or thick and encrusted 
Notes on the Blue-green Alge, etc. 
long; two or four granules on transverse 
walls. Thermal or in brackish or fresh 
water. | (G,, 167; 4,20; UT.) 98) 4, 66). 
with lime : ie 
27. Trichomes more than 2 mic. ‘in diameter .. 
27. Trichomes less than 2 mic. in diameter 
28. Sheath not present 
Stratum thin, bright blue-green or 
obscure green; trichomes 4-10 mic. in 
diameter, straight, fragile, constricted at 
joints; apex not tapering, not capitate ; 
apical cell with slightly thickened mem- 
brane; cells 2-6-5 mic. long; trans. walls 
with granules. In stagnant water, fre- 
quent; on rocks and trunks of trees; 
on mud by the roadside, margins of ponds, 
etcN in (Ga22otgs 2) sai 7a) a, ener 8.) 
Var. natams and var. tergestina (See G., 
220). 
28. Sheath present and usually visible 
29. In fresh water ; 
29. In warm 
Stratum dark green; trichomes 12-15 
mic. in diameter, straight or flexuose, not 
constricted at joints; apex tapering, 
capitate, hooked or terebriform; apical 
cell convex or flattened with slightly 
thickened membrane; cells 2-4 mic. long. 
In fresh water, on rocks in streams, in 
aitches sete. n((Ge ~200) OF, tO 1 il soa, 
4, 4-) 
transverse walls not eranulated, 0. proboscidea 
Jae 
Aha 
67 
69 
O. tenuis 
55 
or fresh waters ; transverse walls granulated, O. sancta 
Stratum dark lead-coloured, violet when 
dried ; trichomes 10-20 mic. in diameter, 
straight or curved, constricted at joints ; 
apex slightly tapering, sub-capitate, 
calyptra convex conspicuous; cells 2-5-6 
mic. long. In warm and fresh waters, on 
wood and earth, in greenhouses, etc. (G., 
ZOO O; 02 le One Aas) 
Var. caldariorum and var. equinoctialis 
(see G., 210.) 
29. In salt water 
30. Plants floating 
30. Plants in warm or fresh water, on 1 stones, wood, 
or aquatic plants, or in salt water . 
31. Stratum 
31. Stratum 
incrusted with lime 48 ue Os beggiatoiformis 
Trichomes 4-5 mic. in diameter, more 
or less lax spiral or sub-erect, fragile, not 
constricted at joints; cells 4-7 mic. long, 
dissepiments with large granules; apex 
tapering, capitate ; apical cell with conical 
calyptra. In acidulated water (Hungary). 
(G. 235, 7, 25.) 
not incrusted with lime 
32. In warm or fresh water 
32. In brackish or salt water 
1913 Sept. 1. 
(Zo be continued). 
Ww NS 
Vo WN 
U1 
Ww 
36 
Sif 
5x 
