THEORETICAL STRUCTURE. 41 



SI, Tlie ovuLEgf'are certain little globular bodies, produced in 

 the cells of the ovary, destined to become the seeds in the 

 matured fruit.} (Fig. 10; 1.) 



82. The PLACENTA (is that part of the ovaiy from wliich the 

 ovules arise, and to wliich they are attached/' It consists of a 

 Hne, or fleshy ridge, placed in some angle of the cell. Its direc- 

 tion is always vertical, that is, parallel with the axis of growth. 

 (Fig. 10; l,d.) 



83. Physiological structure. The ovary and style are com- 

 posed cloieflyfof one or more bundles of vascular tissue, imbed- 

 ded in cellular tissue^ The stigma consists of a loose cellular 

 substance, called the conducting tissue, communicating with the 

 placenta tlnough the centre of the style. It is the only part of 

 the ascending axis which is destitute of \ih.efe2ncler'mis){Z5). 



84. Theoretical structure. The pistil, as before stated (25, a),"is tlie modifica- 

 tion of a leaf, or of a -vvhorl of leaves, each leaf constituting a cai-pel,,) Each 

 carpel has its own style and stigma, and is formed of a leaf folded together in 

 such a way that tlxe upper surface becomes the inner, and is turned towai'ds tho 



The 15th class, Tetradynamia, is divided into two orders, Avhicli ai'C distiaiguished 

 by the form of the pod : — 



1. Siliculosa, the fruit a silicic, or short pod. 



2. Siliquosa, fruit a silique, or more or less elongated pod. 



The orders of the 16th, 17th, 18th, 20th, 21st, and 22d classes are of the same 

 name and character as the first 13 classes themselves, that is, they ai-e founded 

 upon the number of the stamens to the flower, thus : — 



Order 1, Monandria, includes aU Monadelphous plants, Diadelphous plants, &c. 

 with one stamen to each flower. 

 2, Diandria, with two stamens to each flower, and so on. 

 The oi-ders of the 19th class, *Syngenesia, are five: — 

 Order 1. Equalis (e_ciual), with the florets (flowers) of the head all perfect. 



2. Supcrflua (superfluous), florets of the rays, or margin of the head pistil- 



late, the rest perfect. 



3. Frustranea (frustrated), florets of the margin neutral, the rest perfect. 



4. Necessaria (necessary), florets of the margin pistillate and fertile, the rest 



staminate and sterile. 



5. Scgregata (separated), each floret having its own proper calyx. 



The orders of class 23d, Polygamia, are two, founded upon the same characters 

 Jis the two preceding classes : — 



1. Monoecia, where both separated and perfect flowers are fomid in the same 



individual. 



2. Dicecia, where the different flowers occiipy difierent individuals. 



The orders of class 24th, Cryptogamia, are nine, tho same as the natural order? 

 of this grand division, as Filices, the ferns, Musci, the mosses, &c 



