86 ANGIOSPERMAE—DICOTYLEDONES 



first project beyond the stigma, but consequently come into contact with it, as a result 

 of growth of the style. 



195. A. albida Stev. — 



Visitors. — Loew observed the following in the Berlin Botanic Garden. — 



A. Coleoptera. Coccinellidae : i. Coccinella septempunctata Z. B. Diptera. 

 Syrphidat: 2. Cheilosia sp., po-dvg. ; 3. Eristalis aeneus Scop. C. Hymenoptera. 

 Apidae: 4. Andrena parvula K. J, skg., $, skg. and po-cltg. ; 5. Apis mellifica L. 5, 

 skg. ; 6. Bombus hortorum Z. 5, skg.; 7. B. lapidarius Z. 5, skg.; 8. Osmia rufa 

 Z. S, skg. D. Lepidoptera. Rhopalocera : 9. Vanessa urticae Z., skg. 



196. A. deltoides DC— 



Visitors. — Loew observed a long-tongued bee (Osmia rufa L. 5), skg. and 

 po-cltg., in the Berlin Botanic Garden. 



197. A. caucasica Willd. — 



Visitors. — Burkill (' Fertlsn. of spring fls.') observed — on the coast of Yorkshire — 

 one of the Syrphidae, Eristalis pertinax Scop., freq., skg. 



55. Cardamine L. 



Flowers homogamous or protogynous, white or lilac in colour, with half-concealed 

 or completely concealed nectar. Nectaries 2 or 4. 



198. C. pratensis L. (Sprengel, ' Entd. Geh.,' p. 331; Herm. Miiller, ' Fertili- 

 sation,' pp. 102-4, ' Weit. Beob.,' I, p. 326 ; Kirchner, ' Flora v. Stuttgart,' pp. 290-1 ; 

 Warnstorf, Verh. bot. Ver., Berlin, xxxviii, 1896; Knuth, ' Bl. u. Insekt. a. d. nordfr. 

 Ins.,' pp. 25, 148.) — The white or lilac flowers are large and conspicuous, and insect- 

 visits are therefore more numerous than in the case of most other plants of the order. 

 There are two larger nectaries at the bases of the two short stamens, and two other 

 smaller ones — one outside the bases of each pair of long stamens. The nectar 

 secreted by these four glands collects in the swollen bases of the sepals, and the 

 pouches of the two sepals beneath the larger and more vigorously secreting nectaries 

 are proportionately larger than those of the sepals beneath the two smaller nectaries. 

 As Hermann Miiller remarks, the position of the two short stamens can be recognized 

 by looking at the under-side of the calyx. The sepals are closely applied to the 

 petals, so that the claws of the latter are held together so as to form a tube several 

 milimetres long, in the bottom of which the nectar is concealed. C. pratensis therefore 

 belongs to the flower class C. Even in the bud the long stamens project beyond the 

 stigma. They also make a quarter-turn towards the adjacent short stamens, so that 

 insects probing for nectar touch the stigma and the pollen-covered anthers with 

 opposite sides of their heads. It follows that if they probe the flower first on one 

 side and then on the other self-pollination is effected, but if they work round it cross- 

 pollination may result. The two short stamens always turn the dehisced sides of the 

 anthers towards the stigma. These anthers in many flowers are at a lower level than 

 the stigma, or they may be at the same or a higher level. In the last two cases 

 automatic self-pollination is possible. During cold rainy weather the rotation of the 

 long stamens is either slight or does not take place at all, so that pollen falls upon 

 the stigma. Yet according to Hildebrand (Ber. D. bot. Ges., Berlin, xiv, 1896), the 



