OVULES. 



277 



indefinitely numerous. They may also be indefinite or variable 

 in number when not particularly numerous. 



517. As to situation and direction within the ovary, the terms 

 are somewhat special. Ovules are erect, when they rise from 

 the very bottom of the cell, as 



in Fig. 580 ; ascending, when 

 attached above its bottom and 

 directed upward, as in Fig. 579 ; 

 horizontal, when borne on one or 

 more sides of the cell and not 

 directed either upward or down- 

 ward, as in Fig. 314, 315, 530; 

 pendulous, when more or less hanging or declining from the side 

 of the cell ; suspended, when hanging from the apex of the cell, 

 as in Fig. 581. 



518. The body and only essential part of an ovule is its 

 NUCLEUS. This in most cases is invested by one or two proper 

 coats. The coats are sacs with a narrow orifice, the FORAMEN. 

 In the seed, the closed vestige of this orifice is termed the 

 Micropyle ; wherefore this name is sometimes applied to it in 

 the ovule likewise. When the ovule has two coats, the foramen 

 of the outer one is called EXOSTOME, of the inner ENDOSTOME ; 

 literally the outer and the inner 



orifice. The coats themselves have 



been named PKIMINE and SECUN- 



DINE, but with an ambiguity in the 



application which renders these 



names unadvisable : for in their &- 



formation the coats appear later 



than the nucleus, the inner coat c - 



earlier than the outer ; and the 



name of primine has by some 



writers been applied to the earlier 



formed, by others to the external coat. The proper base of the 



ovule, from which the coats originate and where these and the 



nucleus are confluent, 13 the CIIALAZA. The attachment of the 



ovule to its funiculus or support, which in the seed becomes the 



FIG. 579. Ovary of a Buttercup, divided lengthwise, to display its ascending ovule. 

 580. Same of Buckwheat, with an erect ovule. 581. Same of Anemone, with a sus- 

 pended ovule. 



FIG. 582. Diagrammatic section of a typical or orthotropous ovule (such as that of 

 Fig. 582<z), showing the outer coat, a, the inner, &, the nucleus, c. the chnlaza, or place 

 of junction of these parts, d. (The coats are never so separated and the nucleus so re- 

 duced in size as is represented in this mere diagram.) 583. An ovule similar to the 

 preceding, but curved, or campylotropous. 584. An amphitropous ovule. 



