Dr Dickson on Diplostemonous Flozaers, dc. 255 



that some members of a primary whorl may be provided 

 with accessory lobes, while others are not. Eegarding this 

 objection, it is sufficient for me to advert to the remarkable 

 condition of the calyx of the hundred-leaved rose, where 

 only two sepals are provided on both sides with lateral 

 lobes : two of the remaining three being destitute of them, 

 and the other having a lobe on one side only. 



In Cardiospermum (fig. 10), tlie number and position of 

 the stamens are exactly the same as in Koelreuteria : the 

 stamens superposed to the petals being reduced to three, 

 and alternating with the same sepals as in that plant. It 

 cannot be doubted that, in the two cases, the androecia are 

 essentially the same, although it is to be remarked that, 

 while the three carpels are, in Koelreuteria, superposed to 

 sepals 1, 2, and 3, in Cardiospermum they alternate with 

 sepals 1 and 4, 4 and 2, 5 and 3. In Cardiospermum, how- 

 ever, the stamens in each whorl, instead of appearing simul- 

 taneously, as in Kcelreuteria, are developed in a remarkable 

 succession, which I have indicated by the numbers accom- 

 panying the stamens in the diagram (fig. 10). In the first 

 place, the two stamens which alternate with sepals 1 and 4, 

 4 and 2, make their appearance ; next, the two stamens 

 superposed to sepals 1 and 2 ; then, the three stamens 

 superposed to sepals 3, 4, and 5 ; and lastly, the stamen 

 alternate with sepals 3 and 5.* Payer has endeavoured to 

 render intelligible the remarkable mode of staminal succes- 

 sion, in this and other analogous cases, by supposing that 

 the irregularity of development, which so frequently mani- 

 fests itself after the appearance of floral parts, is congenital 

 in such cases ; and it is hardly possible to doubt that his 

 explanation is correct. The anomalous succession is evi- 

 dently the effect of a disturbing force delaying or arresting, 

 for a time, the appearance of some of the parts, and thus 

 materially affecting the order of staminal evolution. This 

 disturbing force seems to act in quite an arbitrary manner, 

 as it affects different plants in very different manners : thus 

 — to take examples from Payer's work — in Viola odorala, 

 the stamens appear successively from before backwards ; in 

 the Eesedacese, from behind forwards ; while, in Cardio- 



* Organogenie, pp. 150-1. 



