Nr. 1] SUBAERIAL ALGAE FROM SOUTH AFRICA 25 
feature, to be found in all species of the sample, must be attributed 
to åa common origin, possibly being due to external conditions. 
The cells are much inflated, broadly elliptic to nearly globose, 
17—22 u broad, and with a breadth of the constricted nodes of 4—7, 
on on average 56 u. Pl. VIII will further give an idea of their 
shape. 
The inner structure of the cells is not easy to examine exactly 
in å material so incomplete and insufficiently prepared. The chro- 
matophore, however, consists of long and narrow ribbons, one or 
several in each cell conforming to the pictures of KARSTEN. At 
times, these ribbons break up in several small parietal dises. Å 
pyrenoid is wanting. 
This species seems to be an subaérial alga widely spread in the 
tropics, as it has been found in the tropical regions of the new as 
well as the old world: Chili, Costa Rica, the Dutch Fast Indies, Au- 
stralia, and now in South Africa. Although it has been observed and 
examined in course of time by several investigators in nature as 
well as in cultures, it has always been recorded as sterile, its repro- 
duction, accordingly, having been hitherto unknown. It is partieular- 
ly interesting then, that in one of the samples examined I have found 
the reproductive organs of this species (in a sample from dense 
wood above Bluff, along the cross-road to the South African W haling 
Company's station, Nov. 13th, no. 120). Its sporangies are formed 
from ordinary vegetative cells in their swelling to somewhat larger 
dimensions and assuming a nearly spherical appearance. The 
breadth of the sporangies I have found to be 25—31 u. Every vege- 
tative cell seems to be able to grow out into å sporangium; for the 
sporangies grow out quite arbitrarily,singly, two or several in series, 
intercalary or apical, and occur anywhere on the thallus. Now 
there appears something very interesting, viz. that the spores 
formed, are surrounded by a thin, but distinet membrane. Thus, 
they are not zoospores or gametes, as might be expected in åa 
Trentepohlia, but real aplanospores. They are globose, and measure 
7—11 u in diameter, and arise in åa number of FG: in each aplano- 
sporangium. Ås is characteristic of this species on the whole, their 
membranes are also delicate, and on account of the mutual compres- 
sion When lying within the mother membrane, they become some- 
what angular, as it may also be seen that the thin mother membrane 
in places is bowed out owing to the pressure, which is caused by 
them. Pl. XIII fig. 306. The aplanospores are liberated through 
an opening in the wall of the sporangium (fig. 308 and 310). In the 
dried material at my disposal I have not been able to examine 
exactly the inner structure of the aplanospores, as also their fate 
after leaving the mother membrane is still an unsolved problem. 
This ought, by the way, preferably to be examined in fresh and 
living material and in pure cultures. The formation of JUR 
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