INTRODUCTORY LESSONS. x1 
the side of this tube below the cotyledons, instead of 
bursting through between them. 
Do not fail to see for yourself how squash 
embryos pry open their tough coats. Soon after the 
sprout has gained a foothold in the soil, a little knob 
grows on the side of the radicle so as to split more 
widely open the point of the seed coat, as shown in Fig. c. 
Then the radicle stem between the knob and the cotyledons, 
by growing, pries the seed still wider open, as seen at b below. 
Finally, by continued growth, the cotyledons are pulled out 
of the seed coat and upward to the surface of the ground, 
where they expand, and become pretty good leaves. Seeds 
planted edgewise, which of course could rarely happen in nature, can not 
thus free themselves of their seed coats, and it has been proved by a 
French botanist (M. Flahault) that seeds which come up with their coats 
on do not thrive. The seed at } in the figure was first planted the other 
sideup. It was turned over when the knob on theright had begun to open 
the seed. The radicle, which then pointed directly upward, gradually 
straightened, bent downward, and finally the second knob grew, by the 
help of which the seed leaves were in a fair way to get out when the draw- 
ing was made. Some native California plants get 
out of their coats in a similar manner. 
Germination of Albuminous Seeds. 
You have observed that when seeds without al- 
bumen send their cotyledons above ground, the 
seed coats are usually left behind, but the albu- 
-minous seeds named in paragraph 5 retain their 
seed coats often for several days after they come 
= up. Examine the coats after they are thrown off, 
\ and you will find none of the albumen which 
¥) formed the larger part of their contents before 
germination. The enlarged cotyledons tell what 
has become of it, and it is now plain why the 
coats were retained. 
