298 



ORGANOGRAPHY. 



of a similar nature, we have a one-celled ovary converted into a 

 many-celled fruit, by the formation of a number of transverse dis- 

 sepiments. In the Pretrea zanguebarica, a one-celled ovary is 

 converted into a six-celled fruit (jig. 642, 2), by an extension and 

 doubling inwards of the placenta. In Trihulus terrestris, the 

 ovary is quinquelocular, but as it approaches to maturity, each 

 loculus {Jigs. 643 and 644) becomes divided into as many divi- 



Fig. 642, 2. 



Fig. 644. Fig. 643. 



Fig. 642, 2. Transverse section of the 

 fruit of Pretrea zanguebarica. From 



Lindley Fig. 643. A vertical 



section of a loculus of the ovary of 

 Trihuhis terrestris. o, o, o. Ovules, 

 c. Projections from the wall which 

 are commencing to separate the 



cviiles Fig. 644. A vertical section of the loculus of a ripe ovary of the 



same, in which the partitions, c, completely separate the seeds, g. 



sions as there are seeds contained within it, in consequence of 

 a con-esponding number of projections proceeding from its walls. 

 Other examples of the formation of spurious dissepiments pro- 

 ducing changes in the ovary have been mentioned when speak- 

 ing of those structures. 



2nd. Other changes are produced in the ovary as it proceeds 



Fig. 645. 



to maturity, in consequence of the great de- 

 velopment of succulent parenchyma. Thus 

 as already noticed, the thalamus of the Straw- 

 berry (^fg. 645) becomes enlarged and suc- 

 culent, and forms what is commonly termed 

 the fruit, but the real fruit consists of the 

 small dry carpels which are scattered over its 

 surface. The pulp of the Guava, Gooseberry, 

 Tomato, &c., in which the seeds are imbed- 

 ded, appears to be produced from the pla- 

 centas ; that of the Orange, is of a similar 

 nature. 



3rd. Other alterations are produced by the 

 abortion, or obliteration of parts, as the ovary 

 ripens. Thus tlie ovary of the Oak, and 

 Hazel, consists of three cells, each of which contains two ovules, 



Fig. CAr>. Fruit of the 

 Strawberry. 



