74 EVOLUTION OF PLANTS 
the procarp, or carpogonium is, in the lowest forms (Fig. 
20, A), a single cell much like the odgonium of the 
green alge, but there is no contraction of the egg-cell 
preliminary to fertil- 
ization. There is a 
more or less evident 
prolongation, known 
as the trichogyne (¢), 
developed from the 
carpogonium, and the 
motionless sperma- 
tium, on coming in 
contact with this, 
fuses with it and the 
walls of both cells are 
dissolved at the point 
of contact, and the 
contents of the male 
Fig. 20. — Fructification of the Red Algze ; : 
A, procarp, or female organ of one of cell pass into the 
the simpler Rhodophycee, Batracho- ‘ 
spermum; ¢, the trichogyne; c, the trichogy ne and effect 
carpogonial cell; B, the same after fertilization. It is 
fertilization; an, the spermatium 
united with the trichogyne; sp, spores probable that in most 
budding out from the carpogonial cell; : . 
C, the antheridium of Polysiphonia; cases there is a fusion 
D, the multicellular procarp of Sper- : 
mothamnium; ¢, the trichogyne; E, of the nuclei of the 
diagram.of the procarp in the higher ‘ 
Rhodophycez ; t, the trichogyne; x, the spermatium and. car 
auxiliary cell which is secondarily i i 
fertilized and produces the spores. Pees but it has 
(Figs. A, B after Davis; E, after been claimed that 
Phillips.) : : 
sometimes this does 
not occur, the fusion of the protoplasm being sufficient 
to insure fertilization. The result of fertilization is not 
a resting-spore as in the green alge, but the carpogo- 
nial cell sends out a large number of short branches 
