PART IIL, | THE MECHANISMS OF FLOWERS. 95 
this species unfruitful in South Brazil, and Darwin found it fruitful 
_ in England, when fertilised with its own pollen. Plants which Fritz 
_ Miiller raised in South Brazil from seed sent from England by 
_ Darwin yielded some seeds when fertilised with their own pollen, 
_ but far fewer than in England. Hildebrand found this species not 
absolutely barren, but very nearly so, when fertilised with its own 
_ pollen (358). 
Orv. FUMARIACE &. 
_  Hypecoum procumbens, L.—In the bud, the two inner petals 
receive all the pollen in two pockets developed upon their inner 
_ surface, and these pockets close up before the development of the 
stigma. On pressure from above, their edges separate and dust the 
‘object pressing them with pollen. The stigmatic papillze do not 
" attain’their full development until some time after the opening 
- of the flower, and after the pistil has grown up above the level 
- of the pollen-sacs, so that in each flower insects come in contact 
| first with the stigma and then with the pollen. Cross-fertilisation 
_ is insured (in case of insect-visits) first by proterandry, and secondly 
_ by the projecting situation of the stigma (358). 
} Hypecoum grandifiorum.—Hildebrand found that the flowers 
_of this species were very nearly though not absolutely barren 
when fertilised with their own pollen or with pollen from another 
flower of the same plant (358). 
«22, -DICLYTRA SPECTABILIS, D‘C.—The heart-shaped pendulous 
+7 lowers contain honey in the two pouches at the base of the outer 
_ semi-cordate petals. Each of these two petals incloses three 
| stamens which follow the contour of its wall and then together 
| form a channel leading from the middle of the flower to the honey. 
; The exserted ends of the six stamens project straight downwards, 
_ lying close together around the pistil, and being themselves sur- 
2 rounded by the hood-like ends of the, two inner petals, which 
_ cohere at the points. 
Li Between the hood-shaped end of the inner petal and the curled 
1 end of the outer one, there remains on the right and left a canal 
leading to the honey. Ifa bee hanging from the flower thrusts its 
| proboscis into one of the two canals, the lower surface of its 
_ abdomen presses both the hood and the flexible stamens towards 
_ the opposite side; and the stigma, which is at the end of a stiff 
‘. ‘style and Pertork escapes being pushed aside, is rubbed by the 
