12 SOUTH AFRICAN BOTANY 
placed at the narrow end. There are two cotyledons 
present, but no endosperm. The radicle is similar to 
that of the sunflower and is found at the pointed end of 
the seed. The testa is thick and tough. During ger- 
mination, the radicle develops a peg which holds the 
c 
wl 
DE errr Seceercres ----5 
em-Uos-e é a é 
Vertical s : 
section 1 - 
through seed TL 
att 
Fie. 8.—Onion Seed Germination. 
ss. Level of soil. ¢. Testa. «. Endosperm. 
em. Embryo. +. Radicle. c. Cotyledon. 
p. Plumule. a7. Adventitious roots. 
seed-coat down, while the elongation of the looped 
hypocotyl drags, the cotyledons out of the case and 
pushes them above ground. If this peg is removed the 
