282 



ORGANOGRAPHY. 



Fig. Gil. Compound irregular 

 ovary of Antirrhinum. 



612. 



he eitlier perfectly even or uniform, 

 thus showing no trace of its internal 

 divisions ; or it may be marked by 

 fuiTOws extending from its base to 

 the origin of the style, and cori'c- 

 sponding to the points of union of 

 its constituent carpels. When these 

 furrows are deep, the ovary assumes 

 a lobed appearance, and is described 

 as one, two, three, four, five, or many 

 lobed, according to circumstances. 

 Sometimes Ave find, in addition to the furrows which correspond 

 to the dissepiments or points of union of the carpels, others of a 

 more superficial character which coi-respond to the dorsal 

 sutures. At the latter points, however, it is more common to 

 find slight projections, which then give a somewliat angular 

 appearance to the ovary. 



The e])idermis covering the surface of the ovary, may be 

 either perfectly smooth, or covered in various ways with ditfer- 

 ent khids of hairs, or prickles ; or it may assume a glandular 

 appearance ; in Avhich cases the same terms are 

 used as in describing similar conditions of the 

 surface of the leaves, or other organs of the 

 plant. 



When the ovary is compound, the number of 

 carpels of Avhich it is composed may be ascer- 

 tained in one or more of the following ways. 

 Thus, when the styles or stigmas remain distinct, 

 tlie number of tliese generally corresponds to 

 the number of carpels. It does, however, occa- 

 sionally happen, as in the Euphorbia (Jig. 612), 

 that the styles are themselves di^'idcd, in which 

 case they would of course indicate a grcatei 

 number of carjiels than are actually present ; wc 

 must then resort to other modes of ascertaining 

 this point, such, for instance, as the furrows, or 

 lobes on the external surface of the ovary, or the number of 

 partitions or loculi which it contains, as these commonly cor- 

 respond in number to the carpels of which that ovary is com- 

 l)Osed. I'lie mode of venation may in some cases also, foini a 

 guide in the determination ; while in others, the manner in which 

 the ovules are attached must be taken into consideration. We 

 will now i)ass to tlie examination of the latter point. 



Placcittation — The term placenta is by most botanists applied 

 to the more or less marked ])rojection occurring in the cavity of 

 the ovary to whicli the ovules are attached ; by others, it is 

 restricted' to the jioint corresponding to the attachment of each 

 ovule, and tlie term placaitaries is then given to the projecting 



Fig. 612. Pistil- 

 late flower of a 

 species of Eu- 

 phorbium, with 

 three divided 

 styles. 



