94 THE FERTILISATION OF FLOWERS. [PART IIT. 
Argemone ochroleuca, Glaucitum luteum, and Papaver argemonoides 
all bear seed when fertilised with their own. pollen (358). 
Papaver Argemone, L.i—The flower has exactly the same 
structure as P. Rhwas, the only difference being that a smaller 
part of the stigmatic lobes is exposed to self-fertilisation. 
In Papaver dubium, L., the stigma stands some millimeters 
above the level of the anthers, so that self-fertilisation can only 
take place in a down-turned position of the flower. Perhaps the 
fact that this species is much rarer than the others (in Westphalia, 
at least) is due to the impossibility of self-fertilisation. 
Papaver alpinum, L., is homogamous, and (when cultivated) 
is sterile to its own pollen. The flowers are devoid of honey, and 
are visited by pollen-feeding Diptera (609). 
Papaver hybridum, L., has cleistogamic flowers, at least when 
under cultivation (369). | 
21, CHELIDONIUM MAJUS, L.—In sunny weather the anthers 
dehisce laterally as the flower opens, and the stigma is developed 
at the same time. Since the stigma somewhat overtops the anthers, 
insects alighting in the middle of the flower touch the stigma first 
and accomplish cross-fertilisation, while those which alight on a 
petal and crawl inwards may accomplish either cross- or self- 
fertilisation. In dull weather the flowers remain closed longer, 
and the stamens dehisce within the as yet unopened flower, causing 
self-fertilisation. 
The flowers contain no honey, and are visited and fertilised only 
by pollen-seeking insects. 
Visitors: A. Hymenoptera—Apide : (1) Bombus pratorum, L. § ; (2) B. 
agrorum, F, §; (3) B. Rajellus, Ill. 9—/(all three alighted on the centre of 
the flower and swept pollen in great haste with the tarsal brushes of the fore 
and midlegs out of the anthers into the baskets on their ,hindlegs, and hardly 
spent two to three seconds on the flower before passing to another ; they effect 
cross-fertilisation regularly) ; (4) Halictus cylindricus, F. 2; (5) H. zonulus, 
Sm. 9; (6) H. sexnotatus, K. 9; (7) H. sexstrigatus, Schenck, 9 —(these 
small bees alight on the anthers and spend a much longer time on each flower, 
passing round upon the anthers. They only come in contact with the stigmas 
accidentally, and may effect self-fertilisation and cross-fertilisation indifferently). 
B. Diptera—(a) Syrphide : (8) Syrphus balteatus, Deg. ; (9) 8. ribesii, L. ; 
(10) Syritta pipiens, L.; (11) Ascia podagrica, F. ; (12) Rhingia rostrata, 
L., all feeding on the pollen, and moving round the flower in the same way as 
the species of Halictus ; (b) Empide : (13) Empislivida, L. See also No. 590, 1. 
Eschscholtzia Californica, Chmss., furnishes an illustration of 
varying capacity for self-fertilisation. My brother Fritz Miiller found 
