ON THE STRUCTURE AND GROWTH OF SEEDS. ^5 



you cut them off. The quantity of hairs that will replace a 

 dilapidated piece in one night is really wonderful. Here 

 therefore Nature plainly speaks her purpose: nor does she 

 less pointedly make it known, when the nourishing vessels 

 decay as soon as the radicle enters the earth. It is such in- but^eray 

 dications as these of the laws and customs of nature, that ^j^.^ ^'^^ ^ 

 should be collected by Botanist? with care, after being 

 thoroughly verified^ and form their axioms, for they cannot 

 mislead. But those which place nature in an unnatural 

 situation, in order to ascertain her rules, I would ever re- 

 ject ; or keep them for trials only, and not build systems on 

 them : for, if the foundation is not secure, how can you 

 trust to the building? I shall say no more on this subject; 

 as a little consideration must I think show, that the idea of 

 the cotyledons nourishing the embryo is a mistake, which 

 will I trust be rectified. T shall proceed therefore to my 

 last subjprt, grieved that my letter has unavoidably spread 

 to such a length. 

 To the division most physiologists make of monucotyledo-Thedivisionof 



nous and dicotyledonous plants 1 should have no manner of P'^"'^ '"*« 



•' . ' , _ , m«nocotyiedo- 



Objection, were it not founded on the mistaken supposition nous and dico« 

 of there beino; plants, that have only one cotyledon, which tyledonousa 



11 iT p 1 mi 1 1 'ii -r 1 1 raistake, as 



Is undoubtedly false. 1 he palms, at least all I have been there are none 



able to procuVe for dissection, have 2, and the grasses either ^'^^ a; ingle 



' , , . ,....,. , cotyledon. 



2 or 4. 1 ne orchises are so very diminutive in their seeds, paims 



that it is not easy for any one to dissect them ; but I have Orchises. 

 been fortunate enough to detect one in a state, that showed 

 its cotyledons in the solar microscope. It is a seed leaf, and 

 has two. The only mosses I have been able to dis.^ect on the 

 same account have visibly two little round leaves from the 

 interior of the pocket, being the usual place; whereas the 

 grasses and palms have their cotyledons rising from the side 

 of the heart, instead of the middle; and what has been 

 taken by botanists for the cotyledons is the prinnordial leaf, 

 whi'ch must of course in both those plants be single, since 

 they grow only leaf by leaf. In the palm, (see PL II, figs. Date paJm. 

 27, 28, 30,) the cotyledons surround the heart, and are in- 

 deed very difficult to be separated from it. Nothing but 

 boiling will do, and then it must be the corculum alone that 

 is boiled. The leaves then peel ofF> and show their number. 



In 



