52 The Botanical Gazette. [February, ; 
or otherwise modified, and although no resting spores were 
observed in any of the sporangia thus attacked, the thick 
walled spherical ‘‘oospores” described by Reinsch® as occut- 
ring, several in an ‘‘oogonium,” are undoubtedly of this na- 
ture. At maturity the dense granular protoplasm within the 
sporangium divides into a large number of zoospores. 
Zoospores.—The zoospores make their escape directly 
through a terminal pore without any interval of rest, swarm- 
ing immediately after emergence and even while still within 
the partly emptied sporangium (fig. 2). They are sub-reni- 
form in shape, biciliate and apparently monoplanetic, although 
this character was not definitely determined. In several in- 
stances when the discharge was observed directly, there was 00 
indication of any process similar to that described by Cornu 
in Rhipidium, where the contents of the sporangium is said to 
be discharged simultaneously as a mass of zoospores which are 
then set free by the rupture of a thin surrounding membrane. 
Antheridia.—The branches which terminate in antheridia 
arise like the zoosporangia terminally or more often laterally 
in whorls of several members and although often associated 
with zoosporangia do not occur in any of the specimens exam 
ined, on plants which produce oogonia. They are much more 
slender than the ordinary hyphe, with few constrictions, — 
often very elongate, flexuous, or often more or less irregularly 
spirally twisted especially just below the terminal anther 
idium. They may be several times branched, and are slightly 
constricted at such points, while the free tips, finding thei! 
way to the oogonia, become rather abruptly swollen into the 
antheridium proper. The antheridia are irregularly cylindr- 
cal, sometimes divided by a septum (fig. 5), and adhere closely 
to the oogonium, often winding partly round it, before reach” 
ing its receptive apex through which an entrance is effected 
by means of a beak-like process, which, pressing the wall ° 
the oogonium inwards, perforates it at the bottom of the de- 
pression thus formed. Two antheridia (fig. 8), or even thret, 
may be applied to a single oogonium invariably at its apex 
their pollinodia penetrating side by side to the oosphett: 
After penetration there seems to be open communication be- 
tween the oosphere and antheridium (fig. 5), but whether any 
interchange of contents takes place between them coul 
be determined from the material examined. As the 00sP0 
*lic. ih: pl 75. f. g-5. 1878. 
4 
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