PROLIFICATION OF THE FLOWER. 13] 
gated (fig. 64) after the fashion of Geum rivale, &c.' 
Occasionally 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 figured in 
Keith’s ‘ Physiological Botany,’ plate ix, fig. 12. 
The change which the calyx undergoes when flowers 
with an habitually adherent ovary become prolified, and 
wherein the calyx is disjoined from the ovary, has been 
before mentioned, but it may also be stated that, under 
such circumstances, the constituent sepals are frequently 
separated one from the other, and not rarely assume 
more or less of the appearance of leaves, as in pro- 
lferous flowers of Umbellifere, Campanulacee, Com- 
posite, &e. 
As to the corolla, it was long since noticed that 
prolification was especially liable to occur in double 
flowers ; indeed, Dr. Hill, who published a treatise on 
this subject, setting forth the method of artificially 
producing prolified flowers s, deemed the doubling to be 
an almost necessary precursor of prolification ;’ but, 
though frequently so,"it 1s not invariably the case that 
the flower so affected is double—e. g. Gewm. If double, 
the doubling may arise from actual multiplication of 
the petals, or from the substitution of petals for sta- 
mens and pistils, according to the particular plant 
affected. Occasionally in prolified flowers the parts 
of the corolla, like those of the calyx, become folia- 
ceous, and in the case of proliferous pears fleshy and 
succulent. There is in cultivation a kind of Cheiran- 
thus? mm 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 
' Bell Salter, ‘Gard. Chron.,’ March 13th, 1847, and ‘ Ann. Nat. Hist..,’ 
1847, vol. xix, p. 471, Ke. 
? “The Origin and Production of Proliferous Flowers, with the Cul- 
ture at large for raising Double Flowers from Single, and Proliferous 
from the oorle. By J. Hill, M.D. London, 1759. 
