170 



ORGANOGRAPHY. 



BOOK I. 



12S 



back of every row, except the in- 

 ner. For example, in the follow- 

 ing diagram (123.), let O be the 





axis, b b placentae, c c the backs of 

 carpels; the placentae, b b, of the 

 inner row will be next the centre 

 O ; the placentae, b b, of the second 

 row will be next the backs, c c, of 

 the first row ; and so on. 



If the order of developement of 

 leaves were exactly followed in that of the stamens and car- 

 ^24 pels, it would happen that the latter 



would be invariably alternate with 



r y- — V, the inner row of stamens; for if a a 



1 ^ / Vly ^-fid' 1^4.) is the station of five sta- 



). '~~y ^^^ mens, b b would be the situations of 



" I the carpels : this relative position is 



therefore considered the normal one, 



( (i) '^^^^ is ill f^ct that which usually ex- 

 ^-'^ ists in perfectly regular flowers; 

 but as all the parts of a flower, 

 in consequence of the non-developement of some parts, or 

 the excessive developement of others, are subject to devia- 

 tions, either real or apparent, from what is considered 

 their normal state, it frequently happens that the carpels 

 either bear no apparent relation to the stamens or are 

 opposite to them. In Papilionaceous plants, for example, 

 where only one carpel is present, it is difficult to say that it 

 bears any exact relation to the stamens, although it is pro- 

 bable that its position is really normal with regard to them ; 

 and so also in Rosaceous plants, with numerous carpels, no 

 exact relation can be proved to exist between the latter and 

 the stamens, unless it may be said to be indicated by those 

 genera, such as Spiraea, in which the carpels are reduced to 

 five; and, finally, in such plants as Delphinium, in which the 

 carpels are three, while the floral envelopes and male system 

 are divided upon a quinary plan, it is manifest that no alter- 

 nation can exist between the stamens and carpels. 



As the sepals and petals most commonly consist each of a 



