1900] Collins, — New England species of Dictyosiphon — 165 
found by the writer at Mount Desert, Maine, in tide pools, in com- 
pany with D. Aippuroides, in July. 
D. Ekmani Areschoug is a smaller plant than any of the species 
yet named, the fronds seldom exceeding five cm. in length. They 
are normally simple, but sometimes have a few short branches. They 
are very slender, in the American form of nearly uniform diameter, 
while in the European form they are considerably larger in the middle 
than at either end. The sporangia are full as large in this species as 
in the others, somewhat larger in the American than in the European 
form. It is a plant of the upper tide pools, growing on Scytosiphon 
lomentarius, which it covers quite densely. It is common about 
Nahant in spring and early summer, extending northeast to the bound- 
ary, and is found also at Yarmouth, N. S. (Herb. Farlow.) 
Though these are all the forms that occur within our limits, it may 
not be amiss to mention two forms that occur in Northern Europe 
and Greenland, and that may be expected to be found on the coast of 
Maine. D. foeniculaceus var. flaccidus Kjellm. has stem and main 
branches tubular, larger than in the type, but soft and easily torn. 
D. corymbosus Kjellm. has a short axis and long, subequal, nearly 
simple branches, not constricted at the base. 
The following summary will give the more important references 
for the species named, and some synonomy : — 
D. FoENICULACEUS (Huds.) Grev. 
Greville, Algae Britannicae, p. 56, Pl. VIII. 
Farlow, N. E. Marine Algae, p. 66. 
Phycotheca Boreali-Americana, No. 673. 
Conferva foeniculacea Hudson, Flora Anglica, p. 594. 
var. FLACCIDUS (Aresch.) Kjellm. 
Kjellman, Algae of the Arctic Sea, p. 268. 
D. flaccidus Areschoug, Observationes Phycologicae, Part 3, p. 31. 
var. AMERICANUS Collins. 
Phycotheca Boreali-Americana, No. 674. 
D. uisPipus Kjellm. 
Kjellman, Algae of the Arctic Sea, page 270. 
Phycotheca Boreali-Americana, No. 677. 
D. foeniculaceus subspecies hispidus Kjellman, Spetsbergens 
Thallophyter, Part 2, p. 39, Pl. II, fig. 1. 
D. urPPUROIDES (Lyng.) Kuetz. 
Kuetzing, Tabulae Phycologicae, Vol. VI., p. 19, Pl. LII, fig. 2. 
