308 



ORGANOGRAPHY. 



valve, therefore, represents one of the component cai*pels of 

 the fruit; or the dehiscence may take place through the dorsal 

 sutures, as in the Heart's-ease {fig. 665), in which case it 

 is analogous to the loculicidal dehiscence, and each valve is 

 composed of the adjoining halves of two carpels. These 

 forms may be readily distinguished by the varying attach- 

 ment of the placentas and seeds in the two cases; thus in the 

 former instance, each valve will bear the placentas and seeds 

 on its two margins {fig. 664), and the valves are said to be 

 placentiferous at their borders; in the latter, the placenta and 

 seeds will be attached to the centre of each valve {fig. 665), 

 and the valves are then said to be placentiferous in their middle. 

 It sometimes happens, as in the fruit of the Chelidonium 

 {fig. 667), and Wallflower {fig. 666), &c., that the placentas 

 bearing the seeds remain vmdivided, and the valves break away 

 from them, so that they are left attached to a frame or replum 

 {fig. 600). 



Fig. 664. 



Fig. 665. 



Fig. 666. Fig. 66^ 



Fid. CM. Friiitofa Gentian dehiscing in a 



septiciflal manner. Fig. fitiS. Fruit of 



Ileart's-ease ( Viola tricolor^, dehiscing in a 



loculicidal manner Fig. Gfifi. Fruit or 



Biliqua of the Wallflower, showing the se- 

 paration of two valves from a replum. 



Fiij. tu;". Fruit of Celandine {Clielidoniuni 

 iri(ijii.i), with the valves separating from 

 tlie placentas. 



In compound fruits with a free central placentation, the same 

 forms of dehiscence occur as in those with ])arietal jdaccnta- 

 tion, but here it is difficult in many cases to speak positively as 

 to the nature of the dcliisccnce, from the absence of seeds or 

 dissepiments u])on the valves. The means usually adoi)ted in 

 such cases, is to count tlic number of the valves and compare 

 their position with that of the divisions of the calyx. Tlius as 



