194 Rhodora [NOVEMBER 
may break up into groups of one, two or more cells, either before or 
after leaving the sheath, as shown in figures 4, 5, and 7. In very young 
hormogones, the line of division between the cells is not clear, but as 
they grow older this line of separation increases in distinctness. The 
color of the hormogones changes as they mature, from the light blue- 
green of the vegetative cells to a very dark blue-green, which under 
the microscope appears almost black. This is probably due to a con- 
centration of material. For this alga I propose the name 
STIGONEMA anomalum sp. nov. Filis liberis, inter algas varias 
sparsis, repetite et irregulariter vel subsecundatim ramosis, 20-36 y 
crassis; ramis patentibus, filo primario nunc aequicrassis, nunc tenuiori- 
bus, omnibus hormogoniferis; vagina 4-8 y crassa, continua, hyalina vel 
ad apices aureo-fusca; cellulis diametro brevioribus, rectangularibus vel 
disciformibus, uni- vel biseriatis, aerugineis; heterocystis lateralibus, 
rarius intercalaribus, fuscis vel coeruleis; hormogoniis terminalibus, 
longitudine variis, usque ad 196 u, aerugineis. 
Filaments unattached, floating among other algae, repeatedly 
branched in every direction, or somewhat secundly, 20-36 u diam.; 
branches patent, of the same size as the primary filament or sometimes 
thinner, all producing hormogones; sheath 4-8 y thick, even, hyaline 
or sometimes golden brown at the apex of a branch; cells shorter than 
their diameter, mostly disciform or rectangular, of one or two series of 
cells, blue green; heterocysts lateral, less commonly intercalary, from 
brownish to blue-green; hormogonia terminal, of varying length, up 
to 196 u. 
Forming loose clumps, free floating among other, mostly blue-green, 
algae, Chebacco Pond, Essex, Massachusetts. 
S. anomalum is a typical Stigonema for the following reasons: It is 
composed of one or two rows of cells; it is repeatedly branched in 
every direction; all branches bear hormogones; the cells are usually 
shorter than wide; the sheath is sometimes colored a light brown. It 
is allied to Fischerella and Hapalosiphon by its tendency to unilateral 
branching; by its smooth sheath; by the first cell of a branch pro- 
jecting into the main filament; and by its generally i... cngular cells. 
Stigonema ocellatum is the only plant that could be confused with 
S. anomalum. I examined the specimen labeled S. ocellatum collected 
by G. T. Moore, in 1897 and distributed in Collins, Holden & Setchell, 
Phyc. Bor.-Am., No. 455, and concluded that my plant was not a new 
one after all, as it agreed very closely with Moore's plant. I then ex- 
amined, through the kindness of Mr. Charles Bullard, the specimen of 
S. ocellatum from the Farlow Herbarium, originally from the herbarium 
of Bornet and Thuret, and decided that Moore had wrongly identi- 
