198 Rhodora [NOVEMBER 
As it seems that there are no well-defined sheaths containing a num- 
ber of trichomes each, it may be doubted whether this plant, notwith- 
standing its size, should not rather be named Phormidium majus, but 
upon the whole its characteristics seem to accord better with Hydroco- 
leum. Maybe there is no hard and fast line between the two genera. 
Stictyosiphon subsimplex, n. sp. Mature fronds from a few 
millimeters to 12 centimeters in length, hardly reaching one half milli- 
meter in width, simple or very sparingly branched. Occasionally a 
frond, otherwise simple, has a tuft of very short branches at the sum- 
mit. Young fronds distinctly articulate. Sporangia (plurilocular ? — 
apparently unilocular) mostly very prominent, often nearly spherical, 
occurring singly or in groups. 
Found at Bridgeport, Connecticut, in a large salt-marsh pool, on 
Ruppia maritima, and only in company with Ectocarpus subcorymbosus 
Farlow, although other species of Ectocarpus are growing at the same 
time on Ruppia and other plants in the same pool. It appears in late 
May or early June and again in autumn. It is, so far as observed, very 
short-lived, appearing, fruiting and disappearing within a very few days. 
Although occurring, so far as yet observed, only in association with Zc/o- 
carpus subcorymbosus, no parasitic or essentially symbiotic relation be- 
tween the two plants is apparent. It is distributed as No. 630 of the 
Phycotheca Boreali-Americana. 
Although this .SZiczyosz?Aon is apparently more substantial than the 
Ectocarpus with which it is associated, it is in reality much more deli- 
cate and extremely impatient of changing conditions. The first collec- 
tion (made Nov. 14, 1897) was left for future examination in a large 
porcelain dish with an abundance of water from the pool in which it 
grew. A day or two later it was found that while the Ec/ocaz?«s was 
in prime condition, the SZicfyosipAom, probably in consequence of the 
temperature of the room having risen too high, had gone to pieces and 
utterly disappeared. 
EXPLANATION OF PLATE 9. — Figures 1-6, Stictyosiphon subsimplex. 1, Several 
plants on Ruppia maritima, which is densely covered with Letocarpus subcorymbosus. 
2, Monosiphonous end of frond, with terminal hair. 3, Somewhat older portion of 
frond, the form of the original cells still showing, though now covered by smaller 
cells. 4, Portion of mature frond, with sporangia and lateral hairs. 5, Portion of 
frond with two very prominent sporangia and a lateral hair. 6, Cross section of frond 
in about the same state as in fig. 4. 
Figures 7-8, Hydrocoleum majus. 7, Trichome with terminal calyptra. 8, Same, 
more highly magnified, 
