TESTA, THE SKIN. 233 



real Cotyledon, as far as air is concerned, and 

 those of the Albumen may be united in these lobes, as 

 is the case with most Leguminous plants ; which is 

 rendered more probable, as several of the latter have 

 the corresponding parts likewise remaininsj under 

 ground. Hence the divided ^i^c/Zw^ of the Cyamus is 

 to be considered as a pair of subterraneous Cotyle- 

 dons, and the plant consequently ranges near its natu^ 

 ral allies the Poppy-tribe, as Mr. Salisbury, without 

 the aid of physiology, has shown in the Annals of 

 Botany, v. 2,/>. 70, 75. 



Testa,/. 4, the Skin, contains all the parts of a seed 

 above described, giving them their due shape ; for 

 the skin is perfectly formed, while they are but a ho= 

 mogcneous liquid. This coat differs in thickness and 

 texture in different plants. It is sometimes single, 

 but more frequently lined with a finer and very deli- 

 cate film, called by Gaertner Membrana, as may be 

 seen in a Walnut, and the kernel of a Peach, Almond^ 

 or Plum. In the Jasmine a quantity of pulp is lodged 

 between the Membrana and the Testa, constituting a 

 pulpy seed, semen baccatum, which is distinct from 

 the Acinus, or grain of a compound berry in the Rasp- 

 berry, the seed of the latter having its proper double 

 covering within the pulp. The Testa bursts irregu- 

 larly, and only from the swelling of its contents m 

 germination. 



Hilum, the Scar, is the point by which the seed i& 

 attached to its seed-vessel or receptacle, and through 



FF 



