THE OVARY. 395 



shows us a single cell or loculus in each ovary. Apparently 

 it is a single reproductive, or carpel lary leaf, which forms each 

 such ovary. We can conceive the carpellary leaf as having folded 

 inwards and its edges grown together. To such an origin points, 

 moreover, the ventral suture, which we find in the median plane 

 of the ovary on its side turned towards the centre of the flower. 

 Such an ovary, composed of one fertile carpellary leaf, is mono- 

 carpel lary ; when a number of such 

 monocarpellary ovaries are found in a 

 single flower, as is the case in our 

 example, the flower is said to be apocar- 

 pous. The ovaries are here free to their 

 base, and inserted upon the summit of 

 the floral axis, i.e., they are superior, 

 or free. The entire female sexual 

 apparatus of the flower may consist of FlG 144 _^ /Vl -,^ //? AJQf . 



one or of many pistils, and is designated <*. Cross-section through an 



. ' , ovary. <>, wall of the ovary ; 



the gy n03C 1 U m , Our cross- section shows ,, ? vascular bundles in the wail ; 



clearly the groove on the ventral side ; ^/^o^le /*' diraentarv 

 and with stronger magnification we can 



here follow the outer epidermis through the entire thickness of the 

 wall, and see it continue into the epidermis of the ovarian cavity. 

 It is interesting that this inner epidermis also possess stomata. 

 The wall of the ovary is traversed by a number of vascular bundles, 

 of which most appear on the dorsal side, and some near the edges 

 of the carpel on the ventral side. The edges of the carpellary leaf 

 are somewhat thickened, and form, on the cavity side, the pla- 

 centae (p). From these the ovules (s), in agreement with the 

 number of placentae, arise in two rows. With the ovules we shall 

 concern ourselves later on, and for this purpose we put our pre- 

 paration on one side. 



Instead of Delphinium, and available so early in the year as 

 February, we can use the pistils of the stinking Hellebore, Helle- 

 borus fcetidus. They agree in all essentials with the above. 

 Sections taken through flower- buds at various stages will show 

 moreover the method of union of the edges of the carpellary leaf. 

 Some of the sections will show these edges unjoined but in 

 contact ; in others, the epidermal cells of one thickened edge 

 will be seen" to grow out, papillately, between the similar cells 

 of the other margin, so as to " dovetail " the edges together. 

 Sections of the same young flower- buds may show the division 



