208 THE FERTILISATION OF FLOWERS. [PART III. 
expansion of the flower. The pouch becomes quite filled with 
pollen, and the anthers withdraw into its lower part. The hairy 
surface of the style and the stigma are thus covered with pollen in 
the opening flower, and each time that the carina is depressed they 
emerge at its apex sweeping a little pollen out. Since the hairs of 
the style do not pass into the lateral pouches, these would remain 
full of pollen, were it not that when the carina is depressed, the 
Fig. 70.— Lathyrus pratensis, L. 
1.—Flower, slightly enlarged, from the side. 
2.—Ditto, from above, after removal of the calyx and vexillum (x 38). 
3.—Inner view of left ala. 
4.—Flower, from above, after removal of vexillum and al. 
5.—Bud about to expand ; the calyx, vexillum, and ale have been removed. 
6.—Fore-part of ditto, from above. 
7.—Style, from above. 
8.—Ditto, from within. : 
a, slight concavity in the ala, which fits into the much deeper depression (a’) in the carina; 
b, infolded process of the margin of the ala, pointing forwards and downwards, and fitting into the — 
narrowest part of the depression in the carina; ec; transverse depression in the ala, into which the _ 
ridge (0) of the vexillum fits; d, posterior alar process ; e, claw of ala; f, incurved margin of ala; 
99, edges of the carina ; h, superior stamen ; i, the coherent filaments ; k k, the entrances to the honey : 
l, claw of carina; m, point where the stigma emerges. when the carina is depressed; n, foliaceous 
expansion developed at the line of junction of the two carinal petals; o, ridge on the inferior sur- 
face of the vexillum, corresponding to a groove on its superior surface; p, bulge in the carina, 
beneath which are the anthers and style,—it is separated by a deep fold from the upper margin of 
the carina on each side. 
empty anthers and the ends of the filaments pass into and push the 
pollen out of the pouches into the apex of the cone, whence it is — 
swept out by the style. It requires considerable force to depress 
the carina, since the style with its hairs has at the same time to be 
forced through the slit at the apex of the carina. 
It stands in close relation to this arrangement that the union — 
of the two halves of the carina is strengthened by an anterior 
Fo fie Te PK, cee 1" 
