AN ERRATIC IVY. 175 



the stimulus created by the birds in the satisfaction of their 

 needs, and the dispersal of the seed would in consequence be 

 facilitated. It is impossible to treat these matters other than as 

 more or less plausible hypotheses, and it seems equally impossible 

 to deny that the appearances in question may be the outcome of 

 recent or temporary conditions, and have no genetic significance 

 whatever. Similar remarks apply to the valvate condition of the 

 carpellary edges. The absence of ovules is clearly a case of sup- 

 pression or complete arrest of development which, if really of 

 genetic significance, points to a former unisexual condition, such as 

 is not uncommon in Umbelliferae. The suppression of the ovules 

 may, however, be correlative with the development of anthers ou 

 the upper margin of the united carpels, and be an exemplification 

 of the process of compensation — redundancy of anthers, defici- 

 ency of ovules. 



The prolongation of the floral axis is clearly due to excess of 

 growth facilitated, no doubt, by the condition of the carpels 

 which leaves an open centre free from obstruction, and through 

 which the elongation of the axis may consequently take place. 

 The formation of a supernumerary flower at the extremity of this 

 prolonged axis is obviously also a case of over-development. This 

 prolification, at least, can hardly be regarded as having any genetic 

 significance. The supernumerary stamens of course suggest the 

 possibility that they represent the condition of affairs in Tupid- 

 anthiis and other Hederaceae, in which the stamens are normally 

 pleiotaxic, but, as before mentioned, the distribution of the vascular 

 cords, as examined by Henslow, shows that the anther-bearing cup 

 is carpellary in its nature. The formation of anthers on the open 

 carpels seems then to be rather a perversion of the ordinary course 

 of development than an absolute mutation of carpels to stamens. 

 We know now that sporangia of this character may be formed in 

 varied organs without any actual change of one organ into another. 

 Substitution has indeed always been recognised as more correctly 

 representing the real progress of affairs than permutation or 

 *' metamorphosis." 



Terminology, when once it gets established, is apt to be con- 

 servative in its application, tyrannical in its sway, stagnant in the 

 midst of change, and misleading to the unwary. Of course, this 

 stability has many advantages, but it seems to point to the desira- 

 bility of making terms, as also names of plants, mere tokens, and not 

 in themselves propositions or statements of fact. Nevertheless, for 

 convenience of arrangement, these monstrous Ivy-flowers may be 

 said to have presented examples of misplacement of the stamens, 

 dialysis and displacement of the carpels, staminody of the ]3istil, 

 suppression of the placentas, ovules and styles, and of median 

 floral prolification. Looked at historically they illustrate arrest of 

 growth and development in some points, excess and superfluity in 

 others ; physiologically they represent almost the greatest degree 

 of interchange possible ; and genealogically they afford abundant 

 ground for speculati(m as to what may have been ! It is to be 

 hoped that next season Mr. Briggs may be so fortunate as to 



