220 
plant separate. 
possible. 
With a power of about 60 diameters examine 
sections from different fronds, searching 
for one kind containing rather large 
ego-shaped cells and another containing 
bundles of numerous smaller sac-shaped 
cells. With a power of 200 diameters 
study the details of the sections. Note 
the character of the cells forming the 
surface of the frond, those of the inner 
structure, and those limiting the cavity 
of the conceptacle. In a conceptacle cut 
through the middle note the form of the 
orifice. Examine the slender hairs or 
filaments (paraphyses) 
which, arising 
at right angles, 
line the walls 
Be sure that some of the cuts pass 
through the conceptacle as near the middle as 
ELEMENTS OF BOTANY 
YY 
. 155, 
Rockweed 
(Fucus). 
A, antheridia borne on branch- 
ing hairs (x 160) ; B, anther- 
ozoids from same ( * 330). 
of the conceptacle. 
Fie. 156. Rockweed (Fucus). 
A, odgonium, its contents dividing into eight 
obspheres (X 160); B, a 
surrounded by antherozoids (Xx 160). 
281. Oogonia and Antheridia. — In con- 
ceptacles containing egg-shaped cells (odgo- 
nia) note the form, mode of attachment 
(sessile or stalked), and different stages of 
development. At maturity the contents 
are divided, forming eight odspheres; but 
not all can be seen at 
once, some being beneath 
the others. 
In conceptacles of the 
other kind examine the 
numerous small sac- 
shaped cells (antheridia). 
At maturity the contents 
of each divide to form 
numerous very minute 
motile antherozoids, each 
n oovsphere, escaped, é . . 
with two delicate hairs 
