MR. M. T. MASTERS ON PROLIFICATION IN FLOWERS. 363 



rivale, where tlie sepals are usually large and leaf-like, as they likewise are frequently in 

 proliferous Roses and Pears. 



Proliferous Eoses have a special interest, inasmuch as they show very conclusively that 

 the so-called calyx tube of these plants is merely a concave and inverted thalamus which, 

 in proHfied specimens, becomes elongated after the fashion of Geum rivale*, etc. I have 

 in my possession a Rose, wherein from the middle of the outer surface of the urn-shaped 

 thalamus proceeds a perfect leaf, which could hardly be produced from the united sepals 

 or calyx- tube ; a similar occurrence in a Pear is iigured in one of the plates of Keith's 

 ' Physiological Botany', sketch 4. 



An important change in the calyx necessarily occurs when flowers with an habitually 

 adherent ovary become prolified, as the calyx is then disjoined from the ovary ; its con- 

 stituent sepals are then frequently separated one from the other, and not rarely assume 

 more or less of the appearance of leaves, as in proliferous flowers of Vmbelliferce, Cam- 

 panulacecB, Compositce, etc. 



As to the corolla, it was long since noticed that prolification was especially liable to occur 

 in doulile flowers ; indeed Dr. Hill, who published a treatise on this subject, setting forth 

 the method of artificially producing prolified flowers, deemed the doubling as an almost 

 necessary precm-sor of prolification t ; but, though frequently so, it is not invariably the 

 case that the flower so affected is double— e. g. Geum. If double, the doubling may arise 

 from actual multiplication of the petals, or from the substitution of petals for stamens 

 and pistils, according to the kind of flower affected. Occasionally in prolified flowers, the 

 parts of the corolla, like those of the calyx, become foliaceous, and in the case of proli- 

 ferous Pears fleshy and succulent. There is in cultivation a kind of CheirantJms ? in 

 which there is a constant repetition of the calyx and corolla, conjoined with an entire 

 absence of the stamens and pistils ; a short internode separates each flower from the one 

 above it, and thus frequently ten or a dozen of these imperfect flowers may be seen on 

 the end of a flower-stalk, giving an appearance as if they were strung like beads, at 

 regular intervals, on a common stalk. I have seen a similar instance in a less degree in 

 a species of Helianthemum. 



The stamens are subject to various changes in prolified flowers ; they assume, for in- 

 stance, a leaf-like or petal-like condition, or take on them more or less of a carpellary form, 

 or they may be entkely absent ; but none of these changes seem to be at all necessarily 

 connected with the proliferous state of the flower. Of more interest is the change in the 

 position of these organs which sometimes necessarily accrues from the elongation of the 

 axis and the disjunction of the calyx : thus in proliferous Eoses the stamens become strictly 

 hypogynous, instead of remaining perigynous. In TJmbellifercB the epigynous condition 

 is changed for the perigynous, etc. 



The condition of the pistiUary organs in a prolified flower is always worthy of notice. 

 The frequent complete absence of the carpels gave rise to the opinion that the pistil or 

 the pistils were converted into a stem bearing leaves or flowers. Setting aside the morpho- 



* Bell Salter, Ann. Nat. Hist. 1847, vol. xix. p. 471, etc. 



t " The Origin and Production of Proliferous Flowers, with the Culture at large for raising Double Flowers from 

 Single, and Proliferous from the Double." By J. Hill, M.D. London, 1759. 



