198 MANUAL OP BOTANY 



outer surface may be either perfectly even or uniform, show- 

 ing no trace of its internal divisions ; or it may be marked by 

 furrovsfs extending from its base to the origin of the style 

 and corresponding 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-, 01 many-lohed, according to the number of its lobes. Some- 

 times we find, in addition to the furrows which correspond 

 to the lines of union of the ovaries, others of a more super- 

 ficial character which correspond to the dorsal sutures. At the 

 latter places, however, it is more common to find slight projec- 

 tions, which then give a somewhat angular appearance to the 

 ovary. 



When the ovary is compound, the number of carpels of which 

 it is composed may be ascertained in one or more of the foUow- 



FiG. 430. Fig. 431. 



Fig. 430. Pistillate flower of a species of Euphorbia, witli tliree forked styles. 

 Fig. 431. Vertical section of the flower ot tlie Stonecrop. pi. Placenta of 

 one ot the ovaries, arising from the ventral suture. 



ing ways. When the styles (fig. 416), or stigmas (fig. 346), 

 remain distinct, the number of these generally corresponds to 

 the number of carpels. It does, however, occasionally happen, 

 as in Euphorbia (fig. 430), that the styles are themselves 

 divided, in which case they fail to indicate the number of 

 carpels that are actually present ; we 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 correspond in number to the carpels of which that 

 ovary is composed. The mode of venation may in some cases 

 also form a guide in the determination; while in others the 

 manner in which the ovules are attached must be taken into 

 consideration. AVe now pass fo the examination of the latter 

 point. 



