POLYSIPHONIA 141 
diversity in size, habit, length and diameter of segments, form of 
cystocarps, etc., and we do not feel confident that all should be 
identified with a single species. The plants forming small tufts 
on Caulerpa are perhaps especially open to suspicion. Some of 
the specimens cited are mere fragments picked out from among 
other algae. The mode of branching in all of the specimens is 
less pinnate than indicated by the figures of Р. abscissa published 
by Hooker and Harvey and by Kiitzing, but is on the whole not 
very different from that shown in Hooker and Harvey's figure of 
P. microcarpa, which species was later merged by Harvey with 
Р. abscissa. Тһе types of both Р. microcarpa and Р. abscissa were 
from the Cape Horn region. Тһе segments іп all of the specimens 
are rather short, perhaps averaging 11% times as long гв broad. 
In some (е. g., no. до) the lower segments become 3-4 times as long 
as broad and show spirally twisted pericentral siphons. Hairs 
г "leaves" often seem to be entirely wanting, as in Kützing's 
figure, and in such cases the plants are more or less suggestive of 
Streblocladia camptoclada, but the segments are much longer 
both actually and relatively, the filaments are commonly more 
slender, and the apices are not recurved. The cystocarps as a 
rule are not conspicuously urceolate or coronate but in no. 30 
they may меке wo; m 
spores. 
Polysiphonia abscissa is closely related to P: urceolata (Lightf.) 
Grev. Harvey has remarked* of it, “The species represents P. | 
formosa and P. urceolata in the Southern Ocean, and is probably 
as variable as those forms are well known to be." The shorter 
segments and certain not easily definable differences in habit 
appear to be the best characters for distinguishing the species 
from P. urceolata. The segments of the Peruvian plant are 
probably shorter than those of P. abscissa and P. microcarpa as 
originally described from the Cape Horn region. It is of interest 
to note that Hariot recognizes both P. urceolata and P. abscissa 
in te oor sx Сар 
Horn. 71% ies 
* In Hook. 1. FI. Tasm. 2: 299. бо. 
ts: 104, 105. T. 
