72 PHARMACEUTICAL BOTANY 
latter divisible into pinne or lobes and pinnules, upon which last 
sort are developed. 
ALTERNATION OF GENERATIONS.—It will be observed that in 
the life cycle of the Male Fern there occur two distinct genera- 
Fic. 40.—Pteris (The brake fern). A. Early stage in development of embryo 
from odspore showing division of octant cells to form: f, foot rudiment; s, stem 
rudiment; 4, first leaf rudiment; w, root rudiment. 8. Later stage in the develop- 
ment of embryo; f, foot embedded in archegonium (aw) of prothallus (fr); s, 
young stem; 4, young first leaf; w, young root. 4, after Kienitz-Gerloff; B, after 
Hofmeister. (From Strasburger’s Lehrbuch der Botantk.) 
Sporophyte 
Stage 
eww aie he awe eww es ee 
—-_—-—— 
\5Q90 | F 
;' 4€© 3 
G0<*&) -©<— 
: Fic. 41.—Diagram of life-cycle of afern. 1, Mature sporophyte; 2, sporangium; 
» Spore — cell; 4, tetrad; 5 spores; 6, germinating spore; 7, prothallus; 8, 
archegonium; 8a, antheridium; 9, ovum; 9a, antherozoid; 10, fertilization; 11, 
zygote. (Gager.) ; : 
tions, one, a sporophyte or asexual generation which begins 
with the zygote (or odspore) and ends with the division of the 
spore mother cells to form tetrads of spores; a second, the 
