2 5 
Origin and Development of the Composite?. 
distinguished from the Cynareae. That a bilabiate corolla is not a 
character of tribal rank is obvious from the large number of cases 
where it occurs in other tribes. 
In the Astereae the corolla of the ray florets in Hinterhubera 
(Fig. 10, S), Remya and Nidorella is bilabiate. 
The only genus in the Heliantheae which shows normally a 
bilabiate corolla is Tridax. Here the corolla of the ray floret is of the 
3 + 2 type in some species (Fig. 19, T), the two posterior lobes being 
distinct in T. decumbens, L. and very small or completely aborted 
in the other species, such as T. angustifolia. The position of this 
genus in the Galinsoginae strengthens the affinity suggested (Fig. 7, 
Chap. II) between that sub-tribe and the Helenieae, where the bi¬ 
labiate corolla occurs occasionally in several genera. 
These genera of the Helenieae are—1, Monolopia, where the 
posterior lip takes the form of a small protuberance (Fig. 10, U). 
2, Chcenactis , where forms like those given for Helenitim occur 
(see Fig. 9, 4-9). 3, Bahia, where the corolla is sometimes unequally 
and obliquely divided into four or five lobes. 4, Microspernium , 
where the outer florets have normally the 3 + 2 type of bilabiate 
corolla (Fig. 10, W). 5, Pectis, where the disc florets have the 
corolla sometimes unequally 5-lobed. 6, Helenium, (see Fig. 9, 4-9). 
In all cases where there are only one or two rows of ray 
florets they are apt to disappear giving discoid capitula. This 
occurs in all tribes but especially in the Senecioneae and Anthemideae, 
see list given by Murr (62). 
The Filiform Type, 
The term filiform is applied to the very narrow tubular corolla 
(Fig. 10, A) without the expansion into a limb at the top, as in the 
ordinary campanulate, tubular corolla. It is more or less character- 
stic of the Inuleae, which Bentham divides into two series, the first 
five sub-tribes with the female florets filiform, and the other four 
with the female florets bilabiate. This plasticity of the corolla in the 
outer florets in the Inuleae is to be compared with the similar 
plasticity in the Cynareae. 
Outside the Inuleae this type of corolla occurs only in 
Aphantochcete, Olearia , Erigeron, Conyzn, Haastia, Psiada, Adelostig- 
ma, Baccharidinae in the Astereae and Homogyne in the Senecioneae. 
In Erigeron the female florets are usually bilabiate and very narrow 
or capillary but the female florets towards the interior of the 
capitulum are sometimes filiform. 
