118 ORGANS AND FUNCTIONS OF PLANTS. 



The Seed. 



The structure of seeds is no less curious than that 

 of the seed-organs. The regions of a seed are named 

 from the position of the seed-scar which is placed at 

 the base 1 ; the point opposite, the tip 2 ; the upper 

 part, the back 3 ; the opposite to that, the belly 4 ; and 

 between the two, sides 5 . In curved seeds, such as 

 in mignonette, the base and the tip become opposite. 



M. Turpin describes the seed scar, which he observed 

 in 1200 seeds, as consisting of a seed pore, and this 

 again often, if not always, exhibiting a larger seed 

 pore 6 , for the passage of nutrient vessels, and a smaller 

 seed pore 7 for the passage of fecundating vessels. M. 

 Mirbel describes an outer seed pore 8 , and an inner 

 seed pore 9 . The seed scar is sometimes large, as in 

 the horse chestnut, and sometimes small, as in the 

 poppy. It is through the seed pore that the young 

 plant appears in germination. 



The outer coat of the seed may be properly termed 

 the shell 10 , and consists in most cases of a simple and 

 single membrane; but sometimes this is thickish,, fleshy 

 internally, and separable, according to Gaertner, into 

 two coats, an outer n , and an inner 12 , as in the castor 



(1) In Latin, Basis. (2) In Latin, Vertex. 



(3) In Latin, Dorsum. (4) In Latin, Venter. . 



(5) In Latin, Latera. (6) In Latin, Omphaloidum. 



(7) In Latin, Micropylum. (8) In Latin, Exostoma. 



(9) In Latin, Endostoma. (10) In Latin, Endospermium. 



(11) In Latin, Testa, (12) In Latin, Membr ana intern a. 



