136 - ‘SHE SEED. 
and radicle, and may be considered the rudiments of the first 
leaves which elaborate the sap and supply the young plant — 
with nutritious matter, before it can put forth proper leaves — 
to perform this function. In seeds which have little or no — 
albumen, the cotyledons are filled with nutritious matter, — 
which supply the young plant, as in the Pea. Plants are © 
divided into two classes, according as they are provided with, — 
or destitute of, cotyledons in their seeds—the Cotyledonew, 
and the Acotyledonex. 
528. In some plants the cotyledons are abortive, or gToW 
together and to the other parts, and there appear to be no | 
cotyledons. 
529. When there is only one cotyledon, (or if two, when 
they are alternate and not opposite), the plant is called — 
Monocotyled: , as in Wheat, Barley, Rice, &c. In 
cienscetylodenied seeds the gemmule is enclosed within the _ 
cotyledon, which forms a sheath called coleoptilon; and the — 
cotyledon is converted in germination into a thick leaf. 
530. It has been found that tyledonous plants are — 
endogenous. 
_ 531, When there are two opposite se aeah as in the 
Pea and Lupine; or several in a whorl, as in some of the ~ 
_Conifere ; the plant is called Dicotyledonous, In this case — 
_ the cotyledons are converted, during germination, into two — 
leaves, affording nutriment to the young plant. (See Fig. 
56.) 3 
_ 532. It has been found that shevlitadiaend plants are ¢z0- 
genous, ; : 
- 633. The Cotyledons, when filled with nutritious matter, — 
- frequently remain under ground during germination, in 
which case they are called Hypogean, as in the Pea. When — 
_ the cotyledons appear above ground, and assume the age ’ 
_ of leaves, they are epigean, as in the Lupine. : 
dete The leaves into which the cotyledons are converted, — 
