INTEODUCTOEY CHAPTEE. 



ST . 



The whorl within or above the corolla is the androecium, (androecium, figs. 7, E, 

 and 10), and its leaves a,vestamens {stamina, figs. 10, E, and 11). The petiole of the 



stamen is the filament 



[filamentum), and its blade 



is the anther {anthera). 



The dusty parenchyma 



contained in the anther is 



called pollen {pollen, p). 



This pollen leaves the 



anther at a certain period, 



and, falling on the central 



» ,1 J, . , 111. i.ValJfloner. 11. 'Wallflovrer. 



organ OI the nOWer, assists Anclraorani ana pistU (mag.). Stameu (iuag.). 



in the formation of the seed. 



There frequently occur on the receptacle (fig. 10, r) small bodies (gl) which 

 secrete a sweet juice, named nectariferous glands or nectaries {glandulce nectarifercs, 

 nectaria) . 



The whorl within or above the androecium is the xjistil {pistillum., fig. 12). This, 



^ 1 



8. Wallflower. 

 Calyx (mag.). 



9. Wallflower. 

 Petal. 



12. Columbine. 

 Pistil composed of 5 carpels, 

 ■with the scars of the stamens 

 on the receptacle R. 



10. Columbine. 



Ripe carpel partially 



opened at the top. 



14. Pea. Ripe pistil open. 



la. Apricot. 

 Pistil cut vertically (mag.), showing 

 the suspended ovule D, v. stigroa .'*, 

 and axis of style T, ti-aversed by t!;e 

 pollen to fertilize the ovule. 



the central or last of the floral whorls, is composed of one or more leaves called 

 carpels {carpidia, earpella, fig. 13), bearing on their edges small bo.dies called ovules 

 {ovula), destined to reproduce the plant when fertilized by the pollen. The blade 

 of the carpel, which encloses and protects the ovules, is the ovari/ {ovarium, fig. 

 12, o) ; its prolongation upwards into a longer or shorter neck is the style {stylus, t) ; 

 and the stigma {stigma, s) is an organ of variable form, spongy and viscous when 

 young, usually placed on the top of the style, and destined to receive the pollen, 

 which adheres to its surface. 



The substance of an ordinary leaf, however thin, consists of three parts : 

 (1) an upper and (2) an under surface, enclosing (3) a network of fibres and paren- 

 chyma; and a slight inspection will show that a carpellary leaf is constructed on 

 the same plan. Thus in the Pea, the pistil of which is composed of a single carpel, 

 which splits into halves when ripe (fig. 14), the outer portion of the leaf (e) is a 

 thin skin, easily torn away, named epicarp {epicarpium). The inner portion (kn) 



