parru.] THE MECHANISMS OF FLOWERS. 123 
of the lower petal, thrust its proboscis between the two valves of 
the pouch, and thus come in contact both with the pollen and with 
the viscid stigma; the proboscis being thus rendered adhesive 
_ carries some pollen with it out of the flower, and when it is drawn 
out of the next flower in a similar manner it leaves some of this 
pollen either caught by the stigmatic hook or adherent to the 
_papille. Thus cross-fertilisation goes on regularly. In default 
of insect-visits the stigmatic lobe curves over upon the pollen 
~ accumulated in the “spoon,” and is thus self-fertilised. 
On the Alps P. comosa is visited by Lepidoptera, but in Low 
. Germany chiefly by bees (590, IL. ; 609). 
i Polygala alpestris, Rehb., is visited by butterflies (609). 
51. PoLYGALA VULGARIS, L, :—~ 
Visitors: A. Hymenoptera—Apide : (1) Bombus terrestris, L. 9, s., very 
frequent ; (2) B. lapidarius, L. §, s.; (3) Apis mellifica, L. $,s. B. Lepid- 
_ optera—(4) Polyommatus Eurydice, Rott. (Chryseis, W. V.),s. See also No. 
590, II. 
Polygala Chamebuxus, L.—The pollen is stored in a cup at 
the end of the style, beside which is the sticky stigma-disc 
_ The mechanism of fertilisation shows a certain resemblance to 
that of Papilionacee. In both, the stamens and style lie in the 
inferior part of a tubular horizontal flower, at the end of which 
_ they bend upwards, and bear the anthers and stigma. Those parts 
lying in the anterior part. of the flower are in both sheltered by a 
carina formed of coherent petals, and emerge, or at least permit 
_ the stigma and pollen to emerge, when the carina is pressed down, 
as it is by every insect which obtains the honey in the legitimate 
manner. 
In Polygala Chamebuzus, as in Lotus and several other Papii- 
- tonacece, it is not the anthers themselves that emerge when the 
carina is depressed, but only part of the pollen which escapes ; 
and after repeated depressions the stigma also emerges, and 
cross-fertilisation is thus insured. A full description of this 
interesting flower is given in my book Die Alpenbumen. 
Polygala myrtifolia, L., has also, according to Delpino, a floral 
arrangement comparable to that of Papilionacez. The two upper 
petals represent the vexillum ; the lower one represents the carina, 
and like it surrounds the reproductive organs and allows them to 
