336 Notes on the Blue-green Alge, etc. 
apical cell rotund or sub-conical with 
calyptra. In warm water. (G., 179, 5, 
ET, 125) 
21. Trichomes in a lax spiral or irregularly contorted, O. grunowiana 
23. 
23. 
D3. 
25. 
25. 
25. 
Stratum obscure green; trichomes 
fragile, 3°7-5°6 mic. in diameter, some- 
times straight ; apex not, or only slightly 
tapering, sub- capitate, no calyptra; cells 
1-4-4 mic. long, constricted at joints; 
transverse walls sometimes granular. 
(G., 235.) 
22. Apex straight, capitate ; upper part of filament 
may be a lax contorted spiral 
22. Apex more or less curved, capitate 
Trichomes 1-2 mic. in diameter a e 
Stratum membranaceous, thin, pale 
blue-green; trichomes straight, slightly 
constricted ; apex may be curved or bent ; 
apical cell acute-conical, not capitate, no 
calyptra ; cells 2-5-5 mic. long, cell contents 
homogeneous. In fresh water, on pots in 
greenhouses, etc. (G., 169, 4, 23-25; T., 
98, 4, 63-65.) 
Trichomes 2-5-8-5 mic. in diameter.. 
Trichomes 4°5-12 mic. in diameter .. 
24. Trichomes I-1-5 mic. in diameter 
24. Trichomes 3-6-5 mic. in diameter 
24. Trichomes 7:°5-10°5 mic. in diameter .. 
Stratum membranaceous, dark verdi- 
gris-green ; trichomes slightly tapering ; 
sheath may be visible; apical cell obtuse 
conical, calyptra absent; cells 4-8 mic. 
long, trans walls not granular, not con- 
stricted at joints. (G., 175s 5; 5:) 
24. 15-24 mic. in diameter .. 
Thermal, brackish or fresh water ; wes ‘Gueved 
not spiral 
In salt water ; trichomes straight or - curved, fragile 
In stagnant See: apex in a lax spiral : 
Stratum dark blue-green; trichomes 
g-II mic. in diameter, slightly tapering, 
somewhat constricted at the joints ; apical 
cell convex or obtuse, not capitate, no 
calyptra; cells 2-5 mic. long, granules 
frequently on transverse walls; inflated, 
refringent cells here and there. (G., 214, 
6, 15; T., 67, 4, 8.) 
30 
ote on a3it 
P. tenue 
P. crouani 
34 
-» 49 
O. ornata 
26. Stratum leathery, dark violet . : P. purpurascens 
Filaments twisted, entangled, agelu- 
tinated ; trichomes 1:5-2:5 mic. in dia- 
meter, not constricted at joints; apex 
neither tapering nor curved, rounded ; 
calyptra absent; cells 2-4-5 mic, long, 
four granules on transverse walls. Ther- 
mal. {Gi 166) 4g tO); Pento55 4, 505) 
26. Stratum thick, slimy, dull green : P. valderianum 
Filaments flexuose, entangled : tri- 
chomes 2-2:5 mic. in diameter, straight, 
not constricted; apex not tapering, 
rounded, no calyptra; cells 3-3-6-7 mic. 
Naturalist, 
