104 



THE FLOWERING PLANT. 



or curved, and in many cases its exterior is provided with hairs. 

 The stigma is a roughened and viscid region of the pistil. It 

 may be a mere spot or streak, but often forms a distinct projec- 

 tion. The general shape of the ovary may be described by such 

 terms as globular, ovoid, elongated, flattened, &c. It often pre- 

 sents a particular number of sides and angles, corresponding to 

 the number of united carpels. The ovaries of tulip and lily, for 

 instance, are three-sided. Prominent ribs or conspicuous veins 

 may correspond to the midribs of the united carpels. The surface 

 of the ovary is often more or less beset with hairs. One or more 

 ovule-containing compartments (loczdi) may be found within the 

 ovary, and we will now try to ascertain what this has to do with 

 the folding of the carpels. Imagine the five separate carpels of 

 a columbine to fuse together. An ovary possessing five com- 

 partments or loculi would be formed, each of which would have 

 an outer wall formed by the dorsal side of a carpel, and two side- 



w r alls or dissepiment* 

 separating it from ad- 

 jacent compartments 

 (fig. 48, G). The side- 

 walls would evidently 

 be double in nature. 

 Finally, the ventral 

 sutures would become 

 internal, and the ovules 

 would spring from the 

 inner angle of the 

 loculus. This kind of 

 placentation is termed 

 axile. Good examples 

 are found in orange 

 (several carpels), dit- 

 tany (five), snowberry 

 (four), lily (three), and 

 foxglove (two). It is 

 evident that if two or 

 more carpels become 

 united by their edges 

 without any folding, 

 they would form an 

 unilocular ovary, i.e., 

 an ovary with one 

 compartment. This 

 condition is well exemplified in the three-sided ovary of violet or 

 pansy (fig. 51). A cross-section shows that the angles corre- 



FIG. 48.— Placentation and Ovules rafter Prantl). D-G. 

 diagrammatic cross-sections of ovaries. D. simple 

 ovary. E. ovary showing parietal placentation. F. 

 ditto, but tending towards G, which represents axile 

 placentation ; p. placenta ; v.s. ventral suture ; H-K. 

 straight, inverted, and bent ovules ; /. funicle ; mp. 

 micropyle ; int, inf. integuments ; nu. nucellus ; e.s. 

 embryo sac. 



