262 On the Fertilization of the Blue Lobelia. 
with the pollen. Wher an insect leaves one flower and goes 
to another, possibly a flower lower in position and in a later 
stage of development, on another stem or plant, he will very 
likely find the stigma of that flower expanded and protruded. 
If so, it will just sweep his back dusted with the pollen of the 
previous flower; and if he then mounts to a flower higher in 
position and in an earlier stage of development on the second 
stem or plant, he will probably find the anthers in a state to 
give up their pollen to him, and so on. 
The flowers are very commonly out two at once on one 
stem, the lower one with the stigma protruded and unfolded, 
and the upper one with the stigma still within the anther- 
tube, and the anther-tube ready to discharge its pollen at a 
touch. The number of flowers visited by a humble-bee in a 
few minutes is very remarkable. 
It is interesting to watch the gradations of this curious 
structtre in Campanula, Jasione, and Lobelia. All have the 
stamens set upon the calyx; all have the brush on the style 
for sweeping out the anthers; in all the stigmatic surface 
remains closed until the pollen has been swept out; and in all, 
when the stigma opens it turns its back on its own pollen, if, 
indeed, any is then left on the style. But there are great 
differences. 
In Campanula the brush is long and the three-lobed stigma 
large; the pressure of the growing style with its brush against 
the anthers is effected by means of the edges of the lobes of 
the valvate corolla, which are folded deeply inwards, and, 
being opposite to. the stamens, press against their backs as the 
flower opens ; and the transportation of pollen must be effected 
by the moving about of the insect within the bell and against 
the pollen-covered style. ‘There must be a profuse expendi- 
ture of pollen; but even here there seems to be a wonderful 
economy in the bristles, which are not scattered on the style 
promiscuously, but are set on in ten rows apparently opposite 
the ten anther-cells. 
In Jasione the brush is shorter, and the two-lobed stigmatic 
surface quite small; the long thin lobes of the corolla do not 
press the anthers against the brush, but, instead, the anthers in 
the opened flower are syngenesious. ‘Their attachment to one 
another, however, is slight, is at the base only, and does not exist 
in the early bud. The transport of pollen must be effected by 
the insect walking over the numerous flower-heads, and 
amongst and against the long protruding styles, of which 
some in each head are generally pollen-covered, with closed 
stigmas, and others pollen-stripped, with opened stigmas. 
In Lobelia the anthers are short, the brush on the style is 
