27 
Notes on the Corolla in the Composite. 
In a comparatively few genera the corolla shows a tendency 
to reductio ad nihilutn. Baccharis, Conyza, Erigeron, Haastia, 
Heterothalamus, Psidia, in the Asterese; Clibadium and Iva in the 
Heliantheae; Gnaphalium in the Inuleae; Doronicum and Petasites 
in the Senecioneae; and Leria in the Mutisieae all show this 
tendency in some species. In Haastia Sinclairi (32; see Figs. 
16-18) the female florets show various stages down to the entire 
elimination of the corolla. These cases, however, have little 
phylogenetic value and serve only to emphasise the tendency to 
reduction in corolla material, which is discussed later (p. 30). 
The occurrence of a large proportion of the reduction forms in 
the Astereae is of interest since it is suggested (29) that this group 
is the first of a reduction series leading through the Vernonieae to 
the Eupatorieae, and also in connection with the statement by 
Bentham (4) that the Astereae and Inuleae become discoid by the 
disappearance of the ray florets. The floret, in most cases where 
reduction is observed, is female, but the distribution of sex belongs 
more to the study of the composition of the capitulum, a subject 
which is dealt with in detail by Uexkullung-Gyllenbad, 1 and will be 
discussed in its phylogenetic aspect in a future contribution. 
The Vernonieae and the Eupatorieae show similar tubular florets; 
the Astereae show the typical tubular disc florets with bilabiate rays 
and with the above-mentioned tendencies to reduction in the corolla 
and the complete disappearance of the ray florets; the Heliantheae, 
Helenieae, Anthemideae, Inuleae, Calenduleae and Arctotideae have 
the tubular disc and bilabiate ray florets, which is the typical 
arrangement for the order in most genera, the Senecioneae also 
show the typical arrangement, but a comparatively large proportion 
of the genera have discoid or disciform capitula ; the Mutisieae show 
1 This author disposes of the idea that the disappearance of the anthers 
and the enlargement of the corolla in the bilabiate florets of the ray are 
correlated and concludes that such a method of compensation has no influence 
in determining the reduction in the androecium. As evidence he adduces 
numerous examples of (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. 
Figs. 1-3, typical corolla forms. Figs. 4-9, corolla forms in Helenium 
autumn ale. Figs. 10-11, corolla forms in (10) Calendula officinalis, (11) C. pluvialis. 
Figs. 12-15, corolla forms in the Mutisieae. Figs. 16-18, female florets in Haastia 
Sinclairi, (after Uexkiitlung-Gyllenbad). The corolla is shaded. Figs. 19-21, 
transverse sections of young florets (19) tubular; (20) bilabiate ; (21) ligulate. 
Figs. 22-24, sectionsof typesof pollen grains:—(22) Tubiflorse; (23) Seneciovulgaris-, 
(24) Cichoriese. Figs. 25-33, floral development:—(25-27) tubular florets, Senecio 
vulgaris ; (28-30) ray florets, Calendula officinalis ; (31-33) ligulate florets, Taraxacum 
officinale. 
