SEED. 53 



has observed, it does not seem reasonable to separate 

 the arillus from the coverings of the nucleus, as 

 something quite foreign to them, for we know that in 

 Epipactis the primine does not extend over the secon- 

 dine till after impregnation ; whilst in Orchis, (and pro- 

 bably in all the rest of the Orchidese), the primine is 

 completely developed before impregnation ; and there- 

 fore if the mere after- development constitutes an aril- 

 lus, the primine of Epipactis must be evidently such. 

 Its more evident origin from the placenta itself, than 

 from the base of the nucleus, like that of the true ovular 

 coats, is another mark which may be put forward to 

 demonstrate its character. " But," says Meyen, " we 

 find in other cases at the funiculus of the unimpreg- 

 nated ovule, the first condition of the appendage we are 

 here speaking of." A good example of the arillus is 

 seen in the Nutmeg, (a fig. 47) enveloping the seed 

 in the form of a notched and divided covering, forming 

 the Mace of commerce ; at (b), is seen the arillus of a 

 Vetch. 



290. In some seeds whose ovulum was anatropous, the 

 chalaza is seen at the apex of it in the form of ramify- 

 ing vessels, as in that of the Orange ; but in others of the 

 same kind the raphe is more observable, extending as a 

 line or mark from the hilum along the face of the seed 

 to where the chalaza has its situation. Close to, or 

 around the hilum of the seeds of some plants, are little 

 protuberances denominated carunculos. 



291. Within the testa or seed coverings are con- 

 tained the albumen (a), and embryo (b) ; the 



first is often absent, the seed being then 

 termed exalbuminous . 



292. The albumen in ripe seeds is mostly 

 of a white or yellowish colour, though in 

 the Miseltoe it is green, and in Pittosper- 

 inum it is said to be red : its consistence is 

 very various ; mealy, hard, or more or less 

 leathery states of it are seen. Its size and 

 quantity in relation to that of the embryo 



F 3 



