Seeds and their Germination 15 



studying germination, take plenty of time to make simple 

 drawings of each plant. Drawings should be made to show 

 the plumule unfolded. 



In the seeds we have studied the cotyledons have their 

 special work to do. 



The cotyledons of the broad bean simply yield up their 

 food to the growing plant. 



In Zea inais the cotyledon not only gives up its own store, 

 but absorbs and passes on the food in the endosperm. 



A third form is found in the date seed, where only the tip 

 of the cotyledon remains within the seed to absorb the food, 

 while the lower part pushes the radicle down into the soil, 

 where it is safe from drying up. 



The onion does nearly the same as the date. The coty- 

 ledon ia) absorbs the endosperm, {b) places the radicle, 

 ((f) comes up with a loop and brings the delicate plumule 

 safely above the soil, {d) finally escapes altogether, becomes 

 green, and behaves like a foliage leaf. 



The pine and castor- oil seeds have a different habit. In- 

 stead of remaining within the seed-coat where the food is 

 stored, they pull themselves out, bringing the food with them 

 as little caps, which they consume on the way up, and gradu- 

 ally become good-sized foliage leaves. 



Black wattles and the narrow bean cotyledons come above 

 the ground to yield up their food, then wither and fall off. 



The gourd family keeps the cotyledons, which grow and 

 become green. 



Here are seven ways, and you may find others. If you 

 live in the East or near a botanic garden, you should study 

 the seeds of Encephalartos (Kafir bread tree). Which type 

 does it resemble ? 



We have found that cotyledons (i) store food, (2) absorb 

 and pass on food from the endosperm, (3) surround and pro- 

 tect the radicle and plumule, (4) bring them into position, 

 (5) act as foliage leaves. 



In no case have the cotyledons looked like the next leaves. 

 Have you found any more showy than the next leaves ? 



In order to watch the growth without injuring the seedlings. 



