254 GENERAL BOTANY 



besides the oil. The outermost layer of the endos- 

 perm of Wheat, Oats, Paddy, Ragi and Sorghum is 

 very nitrogenous and important therefore as food. 



Where there is no endosperm the cotyledons often 

 contain much oil (cotton-seed) or nitrogenous matter 

 (Beans and other pulses) which make the seeds of 

 great economic value. 



It is worthy of notice that where the endosperm, 

 or the cotyledons (as the case may be) are soft or 

 contain food useful to animals (as in the Castor, 

 Gram, Bean, Sunflower and Cereals) the covering of 

 the seed is hard or tough, but where as in the Date 

 and Coffee it is horny, the seed coat is thin and 

 papery. 



In some cases the inner testa is folded into the 

 endosperm, which then appears to be marked by thick 

 straight or curly lines, projecting inwards from the 

 sides. This is very well seen in the fruit of ARECA, 

 the Betel nut, the seed of ANONA the Custard-apple, 

 and of MYRISTICA the Nutmeg. The endosperm is 

 then said to be ruminate. 



In all these respects, all the plants of any one 

 species are alike, but not necessarily all the genera 

 of a family, though this too is most often the case. 



