Chap. XIII. KEVEESION. 33 



many peloric flowers. That pelorism is not due to mere chance 

 variability, but either to an arrest of development or to reversion, 

 we may infer from an observation made by Ch. Morren, 70 namely, 

 that families which have irregular flowers often "return by these 

 monstrous growths to their regular form; whilst we never see a 

 regular flower realise the structure of an irregular one." 



Some flowers have almost certainly become more or less completely 

 peloric through reversion, as the following interesting case shows. 

 Corydalis tuberosa properly has one of its two nectaries colourless, 

 destitute of nectar, only half the size of the other, and therefore, to 

 a certain extent, in a rudimentary state; the pistil is curved 

 towards the perfect nectary, and the hood, formed of the inner 

 petals, slips off the pistil and stamen in one direction alone, so that, 

 when a bee sucks the perfect nectary, the stigma and stamens are 

 exposed and rubbed against the insect's body. In several closely 

 allied genera, as in Dielytra, &c, there are two perfect nectaries, 

 the pistil is straight, and the hood slips off on either side, accord- 

 ing as the bee sucks either nectary. Now, I have examined several 

 flowers of Corydalis tuberosa, in which both nectaries were equally 

 developed and contained nectar ; in this we see only the redevelop- 

 ment of a partially aborted organ ; but with this redevelopment the 

 pistil becomes straight, and the hood slips off in either direction , 

 so that these flowers have acquired the perfect structure, so well 

 adapted for insect agency, of Dielytra and its allies. "We cannot 

 attribute these coadapted modifications to chance, or to correlated 

 variability; we must attribute them to reversion to a primordial 

 condition of the species. 



The peloric flowers of Pelargonium have their five petals in all 

 respects alike, and there is no nectary ; so that they resemble the 

 symmetrical flowers of the closely allied genus Geranium ; but the 

 alternate stamens are also sometimes destitute of anthers, the 

 shortened filaments being left as rudiments, and in this respect 

 they resemble the symmetrical flowers of the closely allied genus 

 Erodium. Hence we may look at the peloric flowers of Pelargo- 

 nium as having reverted to the state of some primordial form, the 

 progenitor of the three closely related genera of Pelargonium, 

 Geranium, and Erodium. 



In the peloric form of Antirrhinum maj'us, appropriately called 

 the " Wonder" the tubular and elongated flowers differ wonderfully 

 from those of the common snapdragon ; the calyx and the mouth 

 of the corolla consist of six equal lobes, and include six equal instead 

 of four unequal stamens. One of the two additional stamens is 

 manifestly formed by the development of a microscopically minute 

 papilla, which may be found at the base of the upper lip of the 

 flower of the common snapdragons in the nineteen plants examined 



19 In his discussion on some curious nal of Horticulture,' Feb. 24,1863, 

 peloric Calceolarias, quoted in ' Jour- p. 152. 



