ON THS STRUCTURE AND GROWTH OF SEEDS. Q 



this time in on^ respect. In seed leaves they raise them- DifFerence in 



felves, and continue to s:row with the stalk; thoiio-h they ^''^'^^ °'^ i*>^s 



. time, 



show by their outward form, that they have differed in their 



jfirst manner of growing ; while other seeds, having tiie silvery 



and delicate cotyledons, leave them in the earth, where 



they decay with the lobes. I cannot agree with Mirbel, 



that they afterward nourish the plant ; in a very short time 



they (as well as the remnant of the seed) break off, and are 



lost in the earth ; or serve as a nest for some of the numev- 



pus insects, that equally receive their noxirishment from the 



bounty of the Almighty. 



I shall now show the conclusion of the chestnut and grass, ^^"^ of the 

 the former of which differs in a curious manner. It possesses, ^ ®^^""^* 

 like the peach and every other seed, the parts already men- 

 tioned, except the cotyledons, which it is wholly without. Without coty- 

 It is impossible to have watched it more narrowly, and to ^^^'°"^' 

 have magnified it to a greater degree; but it has certainly 

 no cotyledons ; and the reason why it has none is very plain, 

 and shows distinctly the use of the cotyledons. It has such 

 a length of stalk to the leaf, that the seminal leaves (with- Reason of this. 

 out greatly exceeding their usual size) could not cover it. 

 The primordial leaves therefore, with their stalk, shoot from 

 the place the cotyledons usually show themselves at ; and 

 the stalk of course comes from the same. See the heart of 

 the horse chestnut, fig. 15. This very plainly shows, that 

 the cotyledons are of no other use to the embryo, than Use of the co- 

 screening the primordial leaves from the light and air at '^ ^ ^"''* 

 their first formation. The esculus differs in no other man- 

 ner from the peach in its seed ; the holders are longer, but 

 they in reality are no more connected with the interior, than 

 the fruit; which I have purposely avoided mentioning, not 

 to confound it with what nature esteems of so much more 

 consequence. 



As to the grass, it will at first sight appear to possess a Grass, 

 part different from other seeds. After strict examinaticn 

 however, this is found not to belong to the seed, but to the 

 valves of the grass, and to be the excrescence on which the 

 stamens grow : and as to the small head on which the coty- 

 ledons rest, it is certainly a part of the heart, since all the 

 vessels pass through it; and literally is that part, which is 



first 



