292 Rhodora [DECEMBER 
pression, giving an interesting addition to our flora. P. violacea, 
which it resembles in habit and in the extent of the cortication, has 
branches arising in the axils of the hairs; in P. Schuebelerii a branch 
arises in place of a hair. /. O/neyi Harv., the only other of our 
species for which it is liable to be mistaken, has little or no 
cortication, and a more decided tendency to dichotomous branching. 
Spermothamnion Turneri (Mert.) Aresch. is one of the commonest 
algae of southern New England, sometimes being washed ashore in 
such quantities as to give its dark red color to water and beach for 
miles, but its only record north of Cape Cod is a reference by Har- 
vey, Nereis Bor.-Am., part 2, p. 241; “var. variabile, Boston, Dr. 
Durkee.” At Cohasset, Mass., Oct. 12, 1901, the writer found it 
washed ashore rather plentifully, though by no means in such abun- 
dance as had been seen at Newport, R. I., at Nantucket, or in other 
places. Var. variable Harv. (Callithamnion variabile Ag.) has been 
distinguished from the type by having the branching of the erect 
fronds, which arise from a creeping filament, secund or alternate ; in 
the type this branching is chiefly opposite, but occasionally alternate. 
In the Cohasset specimens, while the predominant form was alternate 
or secund, it was not uncommon to find one and the same creeping 
filament producing some fronds with opposite branching, some with 
alternate, some chiefly secund. It would seem that the varietal name 
was hardly worth maintaining. 
Of the species above noted, three have been issued in Collins, 
Holden and Setchell, Phycotheca Boreali-Americana, Fasc. XVIII; 
Cylindrospermum stagnale, No. 856, Spirulina Meneghiniana, No. 852, 
Codtolum pusillum forma Americanum, No. 869. Rhizoclonium erectum 
Dichothrix rupicola and Ascophyllum nodosum forma scorpioides will 
be issued in a later fascicle. 
The fact that the RAizoclonium and the Dichothrix have been 
secured in quantity sufficient for distribution, and that the Po/ysiphonia 
has not, illustrates a principle which the algologist, perhaps more 
than any other kind of botanist, should always keep in mind ; in case 
of doubt, take a large quantity. There is no danger of exterminating 
a species of algae, or of seriously reducing its number in any locality. 
If the plant has passed fruiting, it can do no harm to gather it; if not 
yet in fruit, new plants are certain to take the place of what is gathered ; 
if in full fruit, a supply of spores, sufficient to furnish next year's growth 
a hundred times over, must have been already deposited. The writer 
