Wis. = THE OVULE. 
Fig. 43. Fig. 44. Fig. 45. 
Orthrotopous. Anatropous. Campulitropous. 
The different parts are expressed by the same letters in the 
above figures. See paragraphs 452, 453, and 454, for refe- 
rences. . 
' 457. The nucleus contains the liguor amnios which affords q 
nourishment to the young embryo, and part of which assists — 
to form the albumen; and some recent authors have de- 
scribed it as being covered by three coats, the tercine, qua 
tine, and quintine ; of which the first two become the albu — 
men in the seed, and the last becomes the organ occasionally 
present, called vitellus. This is not often met with, but may 
be observed in the seed in the Nymphceacee and Piperace®. 
The nucleus with its coverings becomes the seed with its — 
coats, to form which is the ultimate object of the whole ap- 
paratus of the reprodiictive organs. : 
458. The ovule is not always enclosed in an ovary, though — 
generally so. In Conifer@ and Cycadew, the ovule is naked, — 
 uneovered by an OP feed tbe pollen is immediately 
to the ovule.. 
