190 1] Collins, — Notes on Algae 291 
sition was that it might be A. pachydermum Kjellm., found in north- 
ern Europe and reported from Greenland by Rosenvinge, but a speci- 
men sent to Dr. Rosenvinge was pronounced by him to be distinct 
from the Greenland plant. The branching seems to be more exten- 
sive than in any genuine Rhizocionium, while the fact that it is con- 
fined to a small basal portion of the tuft, much the greater part being 
quite unbranched, distinguishes it from any species of Cladophora 
known to the writer. On the whole it seems best to place it pro- 
visionally in the former genus. 
RHIZOCLONIUM (?) erectum n. sp. Forming erect tufts arising 
from prostrate filaments, 70-100 p diam., of irregularly shaped, 
very thick-walled cells, 1-2 diam. long, from which arise branches 
either with a few similar branches at the base or simple throughout, 
20-50 p. diam., usually 30 p, cells 3-6 diam. long, branches up to 30 
cm. long, but so much and regularly crisped and curled that the 
tufts seldom exceed ro cm. in height. In tide pools, half tide to 
low water mark, Pemaquid Point, Maine, July 18, 19or. 
Ascophyllum nodosum forma scorpioides (Fl. Dan.) Reinke, Atlas 
Deutscher Meeresalgen, p. 33. Though probably merely a form 
produced by the environment, of one of our commonest rock weeds, 
in its extreme condition it would hardly be recognized as at all con- 
nected. Besides the size being reduced everyway, the flattened frond 
of the type becomes nearly or quite terete, the forkings are more 
abundant, while the lateral branches are few or lacking; vesicles 
and fructification are wanting. It was found at Cape Rosier, Maine, 
July, 1901, forming a matted coating on mud between tide marks, 
among the stems of Spartina, etc. 
Polysiphonia Schuebelerii Foslie, Christiania Vidensk.-Selsk. For- 
hand., p. 3, 1881. At Round Pond harbor, in the town of Bristol, 
Maine, July 14, 1901, the writer found extensive growths of Zostera 
marina near the mouth of the harbor, from low water mark to several 
meters depth. Several kinds of algae were growing on this Zostera, 
and at one place the predominant species over a considerable area 
was a four-tubed Polysiphonia, which appeared to be a delicate P. 
violacea (Roth) Grev. A few specimens were taken, but when ex- 
amined with the microscope, the specific determination was seen to 
be wrong, and it was suspected that it was P. Schuebelerit, originally 
described from specimens from Finmark, and more fully described 
and figured by Rosenvinge, Gr$nlands Havalger, p. 799, fig. 2; 
Pl. I, figs. 1-2. A reference to Dr. Rosenvinge confirmed this im- 
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