4 
James Small. 
systematists. Bentham (see Bib. I, 7) confirmed Brown’s statement 
(10) of the universality of the valvate aestivation of the corolla in 
the family and considered the characters of the corolla as important 
for purposes of classification. Robertson (72) mentions a curious 
point concerning the receptacular bristles in Echinacea spp., which 
protect the flowers from bees and adapt them to butterflies by 
increasing the functional length of the nectar tube beyond that of 
the corolla. 
The only observations of the “ absciss-mechanism ” of the 
corolla seem to be those by Yapp (98). 
In connection with the popular explanation of the enlargement 
of the corolla of the ray florets at the expense of the stamens, 
Uexkiill-Gyllenband (85) adduces numerous examplesof (1) reduction 
in the stamens with no reduction in the corolla, (2) enlargement of 
the corolla with no reduction in the stamens, (3) reduction in the 
stamens with reduction also in the corolla, and (4) reduction in the 
stamens with both enlargement and reduction of the corolla in the 
same species. It may, therefore, be considered proved that there 
is no correlation between the enlargement of the corolla and the 
absence of the stamens in the ray florets. 
The detailed history of the corolla subsequent to Cassini may 
be most conveniently given in various sections as follows:— 
Development. The first account of the floral development in the 
family is by Buchenau (12, 1854), who extended his observations 
in a later contribution (13). Two years later Cruger (22) showed 
clearly that the corolla was differentiated before the pappus, and 
the following year the study of the subject reached its highest point 
in Payer’s clear and elaborate exposition (67). Payer confirmed 
the late appearance of the “ calyx ” and the early appearance of the 
posterior split in the Cichorieae. Weber (89) considered that the 
corolla in the Cichorieae and that of the ray florets in other tribes is 
an entire tube which is split only by the growth of the style and 
stamens when the corolla is quite mature. Kohne (46), Buchenau 
(13) and Payer (67) all agree in observing the early posterior split 
in the Cichorieae and the abortion of the posterior lip in the ray 
florets. Hildebrand (36) gives the usual account with a few figures, 
but Payer’s figures are the best yet published. Cramer (21) treats 
of the Compositae, but considered only the ovule in detail. 
Our knowledge of the development of the corolla was extended 
to the “ Labiatiflorae ” by Hanlein (35) who considered that the 
