Mechanism in the Compositae . 267 
tion of the pollen requires careful observation, as it frequently continues 
after the style branches have diverged. 
(4) Movement is sometimes shown in cut flowers of this species. 
(5) This species has orange pollen and dark purple anthers, and 
the presentation is therefore very easily seen. 
; (6) In Erigeron multiradiatus and Heliopsis scabra the movement 
is greatest when the posterior side of the anther tube is touched, giving 
a movement towards the centre of the capitulum. 
(7) In Gerbera Jamesoni and Perezia multiflora 1 the outer florets are 
much more active than the inner, and the greatest lateral movement is 
towards the centre of the capitulum. In the former half the pollen is 
expelled at the first touch, and the rest at the second. In the latter all the 
pollen is expelled at the first touch. In Gei'bera hybrida the pollen is 
extruded in small quantity, but more rapidly than in the ‘ C ’ type, and the 
movement is towards the touch. 
(8) In Heliopsis gratissimus the anthers are forced apart on being 
touched, and the pollen is presented along the slit, which does not at first 
extend to the base of the anther tube. In the evening, however, the 
stamens are more or less free from each other in this species. This 
breaking of the anther tube has been observed in several other genera, e. g. 
Senecio grandifolius, Celmisia verbascifolia , &c., and has been recorded by 
Moore (10) in Cratistylis conocephala . 
(9) In Helipterum Manglesii the movement towards the touch through 
an angle of about twenty degrees is immediately followed by a movement 
in the reverse direction of about half that magnitude. 
(10) This seems to be a garden variety of Senecio populifolius . 
(11) In Senecio poptdifolius the presentation is very distinct, and if the 
staminal tube is touched at the proper stage the style branches may 
be seen to protrude and diverge immediately the anthers are retracted. 
(12) Centaur ea montan a, C. dealbata , Cirsium Kerneri , and Silybum 
Marianum were recorded in 1915 ( 12 ). 
(13) The mechanism of the lateral movement is very clear in Lapsana 
communis ; the five filaments can be seen quite well. They are slightly 
bent, and if one of them be touched with the needle-point it is seen to 
straighten by contraction while the other filaments become more bent, thus 
tilting the anther tube in the direction of the stimulated filament. 
(14) Irritability of the style has been recorded in the Compositae only 
in the genus Arctotis ( 4 , 9 , and 12). 
(15) An irritable pollen-presentation mechanism similar to that of 
Compositae was observed in Lobelia thapsoides , Cham., in the Temperate 
House of the Royal Botanic Gardens, Kew. 
(16) Among the British species recorded as ‘ irritable ’ by Juel ( 4 ) are 
1 First recorded in 1915 ( 12 ) under the synonym Gerbera multijlora. 
