XXX 
INTRODUCTION. 
or less into the cell, is called the Placenta. Each placenta consists of, 
and often separates into, two parts 5 one belonging to each margin of the 
transformed leaf. 
167. It is apparent, therefore, that when the carpels of a whorl combine 
to form a compound pistil by the cohesion of the contiguous parts, the 
compound ovary so produced will have as many cells as there are carpels 
in its composition, and the placentae will all meet in the axis, or around it; 
or, in other words, the ovules will be borne from the internal angle of each 
cell. It is obvious, also, that the partitions (or dissepiments ) of the com¬ 
pound ovary consist of the contiguous and united sides of the carpels, and 
that each is double, or of two layers. 
168. Although a simple carpel has no proper dissepiment, yet the pres¬ 
ence of a partition is no absolute proof that an ovary is compound ; since a 
spurious partition is sometimes formed by the inflexion of, or a growth from, 
the dorsal suture ; as in the simple carpel of Astragalus (p. 103), and in 
the compound ovary of Flax (p. 72) and Blueberry (p. 261), which in this 
way show twice as many cells as there are component carpels. 
169. Nor, jon the other hand, can a 1-celled ovary be inferred to be 
simple on that account. The more or less distinct styles, or the numerous 
stigmas, or the number of the placentae, indicate the composition. A one- 
celled compound ovary may arise in either of the following ways. 
170. The partitions which actually exist at a very early stage may vanish, 
by the more rapid growth of the exterior, so as entirely or nearly to disap¬ 
pear before the flower opens, forming a free central placenta; as in most of 
the Pink Family (p. 55). 
171. Or, the compound ovary may arise as if from the union of a whorl 
of 2, 3, or more open carpellary leaves, the margin of one uniting with the 
contiguous margin of the adjacent leaf to form a placenta or ovuliferous 
line, without any introflexion at all (as in the Prickly Poppy, p. 26, the 
Violet, p. 43, and Sundew, p. 49), or with more or less introflexion, though 
not so as to reach the centre (as in the Poppy, p. 26, many St. John’s- 
worts, p. 53, &c.). The placentae, being in such cases borne on, or pro¬ 
jected from, the parietes or walls of the ovary (instead of from the centre), 
are said to be parietal. 
172. The number of carpels which make up a compound ovary, of what¬ 
ever sort, is expressed by the terms di-(2-)carpellary^ tri-{3-)carpellary, 
tetra-(4-)rarpellary, penta-(5-)carpellary , and so on. To express the de¬ 
gree of union of the styles, we may either say, style cleft, parted , &c.. de¬ 
scribing according to the appearance, as if an originally solid body had been 
split, &c.; or, more properly, styles united at the base , to the middle , to the 
summit, &,c., thus adapting the language to the actual state of the case. 
* * * * Ovules; Fertilization. 
173. Ovules (149) at first appear like minute granulations, or pulpy 
excrescences of the placenta ; but before the flower opens they have gen¬ 
erally acquired their regular form and structure. 
174. The ovule is commonly raised on a stalk of its own, the Funiculus. 
It ordinarily consists of two coats, an outer, the Primine, and an inner, 
the Secundine, which are developed around the base of a cellular mass, 
the Nucleus, so as at length to inclose it. The coats are, however, open 
at the apex, the mouth or orifice (foramen, micropylf.) of the outer 
being called the Exostome *, of the inner, the Endostome. The base, or 
extremity where the coats and the nucleus join and are fixed to the stalk, 
through which it draws its nourishment from the placenta, forms the 
Chalaza. 
175. In the orthotropous ovule, which is the simplest form of all, the 
whole organ remains straight, as the name denotes, with the chalaza or real 
