GROSS ANATOMT OF FLOWEHINQ PLANTS, xxxiii 



Simple Pistil, — In the simple pistil the ovules actually grow 

 out from the united margins (the ventral suture) of the carpophyll; 

 the internal ridge or projection upon which they are borne is the 

 placenta. Sometimes the ovules are erect — i.e., they grow upward 

 from the bottom of the ovary — and when sipgle appear to be di- 

 rect continuations of the flower-axis. Suspended ovules — i.e., 

 those growing from the apex of the ovary-cavity — are also com- 

 mon. (Fig. xxxir.) 



Compound Pistili — In compound pistils the coalescence may be, 

 on the one hand, of closed carpels, and on the other of open car- 

 pels. In the former case the- pistil has generally as many loauU 

 (cavities or cells) as there are carpels; this is expressed by the 



Fio. XXXIII, 



Cross-sections of compound pistils: 1, 2, 3, 4. unilocular; 5, 

 bilocular; 6 and 7, trilocular; 8, quadrilocular. 1, 2, 3, with parietal placentee; 

 4, with a free central placenta; 5 to 8, with axile placentae. 



terms hi-, tri-, quadri , and so on to multi locular (5 to 8, Fig. 

 XXXIII). Such pistils have aadle placentae — i.e., they are gathered 

 about the axis of the ovary. In the case of compound pistils 

 formed by the coalescence of open carpels, the margins only of 

 the latter unite, forming a common ovary-cavity {unilocular, 

 1, 3, 3, Fig. XXXIII) ; here the placentae generally occur along 

 the sutures, and are said to be parietal — i.e., on the walls. 

 Between such unilocular pistils and the multilocular ones de- 

 scribed above there are all intermediate gradations. In one series 

 of gradations the placentae project farther and farther into the 



