328 



ORGANOGRAPHY. 



Flq. 709. 



formed on the margin of a leaf, as in Biijophyllum calycinum 

 {Jig. 195) and Malaxis paludosa (fig. 196); or if on a free central 

 placenta, as in Primrose, to a bud formed on the axis. Henslow 

 has described a monstrosity of the Mignonette, in which the 

 ovules were transformed into leaAes, and Lindley has also, in his 

 Elements of Botany, figured a similar monstrous development of 

 the ovules in Aquilegia. 



The ovule is in most cases enclosed in the cavity of the 

 ovary; but all plants of the orders Coniferae and Cycadacece 

 are exceptions to this. Thus in the latter order, the ovules 

 are situated on the margins of leaves in a peculiarly metamor- 

 phosed condition, and in the former, at the base of indurated 

 bracts or open carpellary leaves {fig. 709). In both the above 

 cases, as there is no ovary, there is no 

 style or stigma, and the ovules there- 

 fore, instead of being fertilized by 

 pollen applied through the stigma, as is 

 commonly the case, are exposed and 

 fertilized by its direct application. 

 Such ovules are termed naked. The 

 seeds of such plants are also neces- 

 sarily naked, and hence they have 

 been called Gymnospertnous Plants, 

 that is, — plants with naked seeds; 

 while those plants in which the ovules 

 and seeds are distinctly enclosed in an 

 ovary, have been called Angiospermous 

 Fig. 700. Bract or carpellary Plants. It shouldbe noticed howcver, 

 leaf, 6c, of a species of /'/«««, that there are some plants in which 



bearing two naked ovules, or, , , , ^ . ,i i , . 



at its base ; wuc, micropyie the sceds bccomc partially naked in 

 of the ovule. tl^y course of development, as in the 



Mignonette (fig. 650), Leontice, Cuphea, &c., in which cases 

 they are sometimes termed seminude. The only instances how- 

 ever, of plants possessing naked ovules from their earliest con- 

 dition, are in the two orders above alluded to ; this is a 

 circumstance to be jxirticularly noticed, as such a character is 

 always attended with important structural and physiological 

 ditferences. 



Number, and position of the Ovules. — The number of 

 ovules in the ovary, or in each of its cells, varies. Thus in the 

 Poljjgonacea) {fig. 710), Composita;, Thymelacea\ Valcriaiiacea', 

 Dipsacaccre, &c., the ovary contains but a solitary ovule; in 

 the Kubiacea;, Umbcllifcra;, Araliacea), &c., there is but one 

 ovule in each cell. AVhen there is more than one ovule in the 

 ovary, or in each of its loculi or cells, the number may be either 

 uniform and easily counted, when they are said to be dvfinite, 

 as in JEscnlns {fig. 714), &c., — and the ovary or cell is then de- 

 scribed as biovidatc, triovulate, quadriovulate, quinqueovulutc, &c , 



