6 4 
Cutting. — On the Potlination Mechanism of 
out so that the whole structure is about two and three-quarter inches long : 
the calyx tube is about three-quarters of an inch long. The width of the 
tube, at the place where the anthers are placed, is half an inch, and the width 
at the open end of the tube is about three-quarters of an inch (see Fig. i). 
The tube is mostly yellow in colour, with purple spots, and the free portions 
are rose-purplish with purple spots.’ 
C. Young stigma: i, front view; 2 , side view. 
D. Diagrammatic view of flower from below 
(with a slit in the side). E. Diagrammatic longi- 
tudinal section of flower. F. Diagram of anther 
showing the pad touching the style, x ij. 
p. process; p.o. outer process; p.i. inner pro- 
cess ; b. 1 buffer ’ or pad ; a.i. inner anther ; 
a.o. outer anther; f filament; s. style; s.l. 
stigmatic lobe; d. slit in anther lobe.. 
The earlier opening flowers are lighter 
than those that mature later. A 
number of lines run down the corolla 
tube ; these may be interpreted as 
being honey guides, and two marked 
ridges run down the tube anteriorly. 
The lower petals are slightly larger 
than the upper ones, so that the 
corolla is asymmetrical. The flower 
does not completely open in dull 
and cold weather. (This condition 
probably does not occur in its 
native habitat in Yunnan.) The 
position of the flowers seems to be 
determined partly by gravity and 
partly by light, as in the Narcissus. 
No experiments were tried to test 
this statement, but most of the flowers 
. were discovered to have so twisted 
their stalks (their origins are sym- 
metrically placed on the axis) as to 
be facing away frond the wall in the 
garden in which they were growing, 
and towards the south-west. Gravity 
probably has even more effect than 
this upon the development of the 
flower. In the young buds the sta- 
mens are similar and symmetrically 
arranged, and the axes of the anther- 
lobes of each anther are parallel 
with each other and with the fila- 
ment (Fig. 2 , a). As the flower grows older the anther-lobes on the 
shorter stamens become of dissimilar size (Fig. 2, b), and the lobes 
on all four stamens diverge until the axis of the two lobes of each 
stamen are in line and at right angles with the filament at the point 
of origin. This is comparable with the state of affairs in Digitalis . The 
stamens also change their positions relatively to the other parts of the 
flower. As the flowers grow older the filaments of the anthers twist round, 
