330 DR. Е, Е. FRITSCH ОХ FRESHWATER ALGJE 
was first recorded by Hooker and Harvey (* Botany of the Antarctic 
Voyage,” Flora Antarctica, vol. ii. рр. 498-409) as Ока crispa, Lightf., 
as occurring in ** Berkeley Sound, Falkland Islands ; on moist rocks ; 
Cockburn Island, Graham’s Land ; very abundant. They add the comment : 
“a highly interesting species, beeause it is one of the very few terrestrial 
plants that have been gathered on the limits of vegetation both in the 
g 
Northern and. Southern Hemisphere." Subsequently it was recorded by 
Hariot from Cape Horn, by Svedelius from Patagonia, and by Wille from 
Cape Adaire (* Antarktische Algen. Mitteilungen über einige von С. Е. 
Borchgrevink auf dem antarktischen Festlande gesammelte Pflanzen,” in Nyt 
Mag. f. Naturvidenskab. xl. 1902, pp. 209-219). The various authors who 
have dealt with this Antarctic form have held rather different views as to 
the specific determination, several (such as Kiitzing, Rabenhorst, Svedelius) 
regarding it asa distinct species, Prasiola antarctica, IKütz. These different 
views are fully considered in the paper of Wille above cited. On the basis 
of a careful investigation of Borehgrevink's material from Саре Adaire, 
Wille himself (loc. cif. р. 217) comes to the conclusion that there is no true 
point of difference between P. antarctica and P. erispa and that the Antarctic 
form belongs to the widely distributed P. erispa. 
The material from the South Orkneys showed the characters which have 
led the above-mentioned authorities to regard the Antarctic form as a distinct 
species, viz. large interspaces between the areolie * and prominent thickening 
of the outer walls of the cells. In the former respect the South Orkneys 
material differed markedly from the figures shown by Wille (see his pl. iii. 
fiv. 1 and pl. iv. figs. 1 & 2). There can therefore be по doubt that some 
of the Antarctice Prasiola is distinguished from the normal P. erispa by these 
characters, but it may be questioned whether they warrant the establishment 
of a distinct species. The differences, especially as they appear to grade 
into one another to some extent (ef. Wille, p. 217). are not of specific value, 
and the case would perhaps be best met. by regarding the Antarctic type as 
a forma antarctica of P. crispa. [t seems very probable that the normal 
P. crispa also occurs in Antarctic regions side by side with the special form 
and that the material which Wille investigated was the actual Р. crispa. 
My material showed most of the stages figured by Wille in his pl. iii. 
Numerous filaments of the //ormidium-stage were observed, but in many of 
them а considerable number of the cells were dead or dying, and it appeared 
that the filaments were undergoing fragmentation without coming to 
anything further, Stages like those shown in Мех figs. 13 & 14 were 
also not uncommon. Little detached groups of cells, like those of Wille’s 
figs, 11 & 12, were very common in the sediment at the bottom of the 
* In spite of careful investigation I was unable to make out that these areole were 
occupied by fungal filaments, 
