360 MR. M. T. MASTERS ON PROLIFICATION IN FLOWERS. 



I propose on this occasion to treat of Median Prolification alone, reserving the axillary 

 and lateral varieties for another opportunity. In Median Prolification the adventitious 

 bud springs from the centre of the flower ; the usual arrest of growth which occurs at 

 this spot no longer holds good, but a new growth takes place, manifesting itself generally 

 in the formation of a new flower-bud, of a new leaf-bud, of a branch, or even in the pro- 

 duction of an inflorescence. The new growth may occur whether the carpels be present or 

 not ; if present, then it may emerge from among or between them, or it may originate 

 within the cavity of the carpels. 



Certain of the European families of plants (to which, with few exceptions, these remarks 

 alone apply) present this deviation from their ordinary structure with greater frequency 

 than others : thus the following orders seem to be the most frequently affected by it — Ba- 

 nimcidace(je,Canjophyllacece, Bosacecs; while it is commonly met with in ScroplmlariacecB, 

 Frwmlacece, and Umbelliferce. Of genera which seem peculiarly liable to it, I may men- 

 tion the following — Anemone, Bammculus, Cheiranthus, Diantlms, Dictammis, Demons, 

 Bosa, Geum, Fyrus, Trifolium, AnUrrUnum, Bigitalis, Primula. Appended to this 

 paper is a list showing the orders and genera in which prolification is recorded to have 

 occurred, and specifying whether the new growth take the form of a flower-bud or of a 

 leaf-bud ; the latter condition is, as Linnaeus long since remarked, much less common 

 than the former. The list must not be considered as complete ; but from the abundance 

 of material at my disposal it may, I hope, be esteemed sufficiently so to illustrate and 

 give colour to the remarks and opinions that I now venture to bring before the Society. 



A reference to the list of genera affected by this malformation, and the knowledge of its 

 comparatively greater frequency in some than in others of them, will show that it is more 

 often met with in plants having an indefinite form of inflorescence than in those having 

 a definite one. It would seem probable that there may be some real relation between 

 the conditions ; but I am not prepared at present to affirm the existence of anything more 

 than an apparent relation. 



The change may affect some only, or the whole of the flowers constituting an inflores- 

 cence ; and though it is by no means a constant occurrence, it very frequently happens 

 that the central or terminal flower in a definite inflorescence is alone affected, the others 

 remaining in their ordinary condition, as in Pinks ; and in the indefinite forms of inflo- 

 rescence, it is equally common that the uppermost flower or flowers are the most liable 

 to be thus affected. 



In those plants which present this deviation from the ordinary condition with the 

 greatest frequency, it often happens that the axis is normally more or less prolonged, 

 either between the various whorls of the flower, as in the case of the gynophore, etc., or into 

 the cavity of the carpels, as in the instances of free central placentation. To bear out this 

 assertion, I will cite the following instances taken from those genera having definite in- 

 florescence, and which are very commonly affected with prolification : thus, in Anemone 

 and BanuncuJus the thalamus is prolonged to bear the numerous carpels ; in Diantlms 

 there is a marked internode separating the carpels from the other parts of the flower ; in 

 PrimulacecB central prolification is very common, and this is one of the orders where the 

 placenta seems, from the researches of Duchartre and others, to be truly a production of 



