Plants and their Ways in South Africa 



Instructions for Work. — Make a drawing of the outside 



of a bean seed. Carefully look 

 to see how the parts are placed 

 within. At which end of the 

 seed is the plumule with refer- 

 ence to the micropyle? On 

 which side of the seed ? Com- 

 pare the arrangement of the 

 French bean with that of the 

 broad bean. Make drawings of 

 all that you see. Keep these 

 drawings in a book which you 

 will use for plants, or better on 

 separate sheets. 



A loquat seed will separate 

 into two parts, the cotyledons ; 

 but the plumule and radicle 

 cannot be so plainly seen. 



Now make out the parts in 

 the seeds of a pumpkin, water- 

 melon, or calabash seed. 



In all these seeds all the 

 food which the mother plant 

 provided is stored within the 

 two plump cotyledons. But 

 there are seeds in which the 

 food is stored outside the em- 

 bryo. The pine seed shows 

 this nicely. Remove the thick, 

 hard seed-coat and cut the con- 

 tents across. A ring containing 

 food will be seen, the endo- 

 sperm, surrounding a central 

 part. If another is cut length- 

 wise, this central part will be 

 recognized as the embryo, with 

 the radicle pointing to the 

 smaller end of the seed. Instead of two cotyledons, several 



Fig. 9. — Seeds of Pinus pi?iea in 

 different stages of germination. 

 /. Ripe seed in longitudinal sec- 

 tion : s, testa ; e, endosperm ; w, 

 radicle of embryo ; c, the cotyle- 

 dons ; y, the micropyle end of 

 seed, with the rootlet directed to- 

 wards it. //. Germination com- 

 mencing: A, Testa ; s, ruptured, 

 and rootlet ; w, protruding ; r, red 

 membrane inside testa ; x, rup- 

 tured embryo sac : B, portion of 

 testa removed ; e, endosperm : C, 

 longitudinal section ; c, cotyle- 

 dons : D, transverse section. ///. 

 Germination complete, the coty- 

 ledons, c, unfolding, and the hy- 

 pocotyledonary part of stem, he, 

 elongated, the main root, iv, de- 

 veloping lateral rootlets, w'. 

 (From Edmonds and Marloth's 

 " Elementary Botany for South 

 Africa",) 



