372 Notes on the Blue-green Alga, etc. 
cells 574-8'2 mic. long, transverse walls 
not granulated; apical 
cell may be 14 
mic. long. In warm water. (G., 231; 
és 81, 4, 34+) - 
. Trichomes 2°5-4 mic. in diameter 
vo 
“I 
straight, fragile, constri 
Stratum dark blue-green; trichomes 
cted at joints; 
apex tapering, curved, not capitate, no 
calyptra, obtuse; cells 
2-8 mic. long, 
transverse walls not granulated. Fresh 
water, on water plants, 
als eo tie) 
38. Transv erse walls conspicuous .. 
etc. o( Gare ates 
Ale 
Stratum incrusted with lime, hard, dark 
red or violet; filaments 
meter, entangled, not 
joints; apex straight, 
cells 3°5-5°2 mic. long. 
sides of water troughs. 
De BoG ade Oe:) 
Var. cataractum, in 
(G., 190.) 
4°5 mic. in dia- 
constricted at 
obtuse conical; 
In streams, on 
(G., 170, 4, 27; 
waterfalls, etc. 
38. Transverse walls hidden by granules 
. Cells longer than broad 
ae Cells usually shorter than their seeds or * equal 
and shorter after division E 
40. Floating; cells 6-8 mic. in diameter, 2- a mic. 
long 
Stratum "purple-violet _ : 
trichomes 
’ 
straight, rigid, fragile, not constricted at 
joints; apex tapering, 
with convex calyptra ; 
frequently granular. (G., 
40. Floating 
long : 
Stratum purple, ‘lilac 
»chomes straight, flexible, 
-at joints ; apex tapering, 
; cells 2°2-5 mic. in d 
slightly capitate 
transverse walls 
204, 6, 6-7.) 
iameter, 4-6 mic. 
when dry; tri- 
not constricted 
capitate ; trans- 
verse walls frequently granular; apical 
cell truncate, calyptra d 
epressed conical. 
On ponds forming a purple floating scum. 
(G., 205, "6268 les (6s 
, 
4, 1.) 
41. Cells 6-8 mic. in diameter, 1°5-2°5 mic. long 
Stratum dark blue-green ; trichomes 
not constricted at joints, 
inflated refrin- 
gent cells present ; apex tapering, twisted, 
in a spiral like a screw, obtuse, capitate ; 
apical cell sometimes 
streams and still water ; 
(Gi, “2a; MOp eon ee GS: 
thickened. In 
on moist earth. 
4, 9.) 
41. Cells 2-3 mic. in diameter, 3-9 mic. long 
Stratum thin or scattered; trichomes 
blue-green, flexuose, elo 
ngate, not con- 
stricted at joints ; apex tapering, capitate; 
apical. cell globular; transverse walls 
slightly granular. In 
stagnant . pools, 
brackish ditches; on mud, wet rocks. 
(G.,- 224,707, BE Dy 76, 
4, 23245, 25%) 
Var. uncinata ; apical cell very long, 
hooked. (T 76.) 
~, 
O. numidica 
incrustatum 
43 
44 
O. rubescens 
O. prolifica 
O. anguina 
O. splendida 
Naturalist, 
