184 THE FERTILISATION OF FLOWERS. [PART III. 
100. TRIFOLIUM PRATENSE, L.—The honey lies at the base of a 
tube, 9 to 10 mm. long, formed by cohesion of the nine inferior 
stamens with each other and with the claws of the petals; it is 
secreted by the bases of the stamens, and accumulates in the tube 
around the base of the ovary. But while in Trifolium repens, as in 
Lotus and most other Papilionacez, only two small openings, one on 
either side of the base of the superior stamen, give access to the 
honey, and compel the bee to thrust its proboscis down to them 
outside the staminal tube, in 7’. pratense the bee’s proboscis, after 
being thrust under the vexillum, passes at once into the staminal 
|! Hf ) ih ; 
Fic. 60.—Trifolium pratense, L. 
1.—F lower, from below. 
2.—Ditto, from above, after removal of the vexillum. : 
3.—Anterior part of flower, twice as much magnified ; the edges of the carina have been forced 
apart. . 
4.—Right ala, from within. ‘ 
5.—Right half of the carina, from without. (The claws of 4 and 5 have been broken short off.) 
6.—The essential organs emerging from the depressed carina. 
a, calyx; b, tube formed by coalescence of the nine filaments with the claws of the vexillum, ale, 
and carina; c, vexillum ; d, concave part of the inner side of the ala; e, lower border of ala, bent 
outwards ; f, outward surface of ala; g, pouched swelling on the base of the ala; h, carina; i, style ; 
k, superior free stamen ; 1, stigma; m, anthers; n, point of union between ale and carina; 0, point 
of flexure of the carina; p, part of the upper border of the ala, bent outwards; q, downward 
extension of vexillum. 
tube, to which in this case the claws of the petals are adherent. 
The insect’s proboscis, passing down the tube in the middle line 
superiorly, would be impeded by the superior stamen which is 
inclosed in the tube if this retained its normal position ; but its two 
ends only are situated in the middle line, and the rest of the stamen 
lies wholly to one side. 
From the anterior end of the common tube come off the 
| 
: 
: 
