1 6 Plants and their Ways in South Africa 



of the cotyledon remains within the seed and absorbs 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 [a) absorbs the endosperm, (b) places the radicle, 

 ((■) 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, the cotyledons pull themselves out, bringing the food 

 with them as little caps, which they consume on the way up, 

 and gradually become good-sized foliage leaves. 



Black wattles and the French bean cotyledons come above 

 the ground, 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 ? Have 

 any borne hairs'? Are they ever compound? 



In order to watch the growth without injuring the seedlings, 

 seeds may be planted in a frame having glass sides. Ask the 

 tinsmith to cut two pieces of galvanized iron the shape of 

 Fig. 23. Bend them along the dotted lines. Nail the piece 

 a-b to a board for support, and slip in on either side a piece 

 of glass. Discarded photographic plates will do nicely. 

 Several may be used. Fill with moist sand. Thin cloth may 

 be placed between the sand and the glass. 



Ex. I. Place the seeds in diflerent positions. Notice how quickly the 

 roots will turn do«'n and the stems bend upward. The work of the roots 



