PHYTOGENY. 237 



added. The pentapetalous corolla is also an odd pin- 

 nate leaf in a whorl-shaped position with four pinnate 

 leaflets. 



1216. The pentapetalous is naturally higher in rank 

 than the tripetalous, and this than the monopetalous, 

 corolla. 



1 217. In the former four petals are of equal rank, but 

 the fifth or odd petal differs from them. This difference 

 is shown in its position, size, form, design, and colour- 

 ing. The odd leaf is usually larger, of a rounded form, 

 having more ribs and other spots or markings. 



1218. It appears as if, with this second liberation of 

 fibrous fascicles from the main bundle, the differentiali- 

 zation were closed. For most corolla? are only quinarily 

 divided, or admit at least of being referred back to that 

 number. 



1219. It is readily comprehended why there are only 

 three breaks present in the number of petals, that these 

 are denoted by one, three, and five, and that they rarely 

 ascend to seven, nine, and so on. For the posterior pin- 

 nate leaflets are wont also to abort or be arrested in the 

 leaves. 



1220. There can be no plant with originally two 

 corolla-lobes or petals ; for the fibrous bundle does not 

 thus divide itself; one main fasciculus is always left. 

 The cause why the principal bundle does not divide into 

 two equal fasciculi resides in the very nature or essence 

 of the stalk. The idea of the stalk operates throughout 

 the whole plant. The odd or uneven leaflet is only the 

 last expansion of the stalk. The even leaflets are its 

 branches. 



1221. For the same reason there can be no originally 

 quaternary corolla. 



1222. There can be none that is originally sexanaiy. 



1223. But an originally septenary corolla is con- 

 ceivable, if forsooth the energy of light is still in a con- 

 dition to separate two bundles of fibres. How rarely 

 this occurs is well known, and thus it still continues 

 doubtful whether this form is not to be explained by an 

 arrest of development. 



