1915] Collins,— Algae from the Chincha Islands 93 
GigARTINA Lesson (Bory) J. Ag. These two species are repre- 
sented each by a well developed typical plant, with cystocarps. 
* GRACILARIA CONFERVOIDES (L.) Grev. A long, slender, little 
branched form; tetrasporic and cystocarpic specimens on the same 
paper. There appears to be no record in print of the occurrence of 
this species on the coast of South America, but Dr. Howe reports 
having received two sterile specimens from Valparaiso, Chile, which 
he places under this species. 
RHODYMENIA CORALLINA (Bory) Grev. In this specimen the frond 
is flat, even to the point of attachment, very regularly dichotomous 
and flabellate; there is no trace of the terete stipe occasionally found 
in this species, always in H. flabellifolia (Bory) Mont. The cysto- 
carps, however, are distinctly apiculate, similar to the cystocarps in 
the plants assigned to R. flabellifolia by Howe, while in the plants 
assigned by him to R. corallina the cystocarps were not at all apiculate. 
It would seem then that cystocarpie characters cannot be depended 
on for the distinction of the two species. 
* PLOCAMIUM CoccINEUM (Huds.) Lyng. forma compactum f. nov. 
ramificatione ad omnes partes densa; axibus principalibus mox in- 
distinctis; pinnulis brevibus, basi contiguis; ramuli fertilis pedicello 
brevi sporophylla brevia, numerosa, dense fasciculata, ferente. 
Branching dense throughout; main axes soon indistinct; pinnules 
short, contiguous at base; fertile branchlets with short pedicel and 
densely packed, short sporophylls. Chincha Islands, Peru, Mrs. 
J. K. Nickerson. Type in herb. University of Maine, Orono, Maine. 
If compared with the slender form of P. coccineum common in 
Europe, the present plant would seem amply distinct, specifically, 
but there is a great variety in habit even in European plants, as will 
be seen by comparing the figures by Turner, Greville? and Harvey.? 
The first two represent the slender form, the last the broader form; 
the Californian plant resembles the latter, and like some other species 
common to Europe and California, is a larger and somewhat ranker 
plant than the European. Forma compactum agrees with the Cali- 
fornian plant in the breadth of the branches of the various orders, but 
the branches divide more frequently, the branch being often of the 
same size as the axis, and giving a subdichotomous appearance. In 
1 Dawson Turner, Fuci, Vol. I, p. 130, Pl. LIX, 1808. 
? R. K. Greville, Algae Britannicae, p. 98, Pl. XII, 1830. 
3 W. H. Harvey, Phycologia Britannica, Pl. CLXXV, 1846-51. 
