6 ANGIOSPERMAEDICOTYLEDONES 



crowded flowers. In young flowers the stigmas mature according to Miiller, 

 partly immature according to Schulz and Ricca are covered by the unripe inner 

 stamens, being thus shielded from contact with insect visitors, which, in this first 

 condition of the flower, get dusted with pollen as they creep about collecting or 

 devouring this kind of flower-food. The inner stamens subsequently ripen and 

 spread out, so that insects alighting in the middle of the flower must necessarily 

 effect cross-pollination if they come from other flowers of the same species. Should 

 insect-visits fail, self-pollination takes place automatically, for the stigmas are situated 

 in the line of fall of pollen from the inner anthers. 



It is also possible that the light and but slightly adhesive pollen may be carried 

 by the wind, but as Schulz remarks anemophily cannot often obtain, for the 

 closely crowded stamens keep pollen from the stigmas. 



Visitors. According to the observations of Hermann Miiller (H. M.), and 

 myself (Kn.), these are pollen-collecting bees or pollen-devouring flies and beetles. 

 A. Coleoptera. (a) Nitidulidae : i. Meligethes (Kn.). (b) Scarabaeidae : 2. Trichius 

 fasciatus L., devouring the anthers (H. M.). B. Diptera. Syrphidae : 3. Eristalis 

 arbustorum L. (H. M.); 4. E. nemorum Z. (H. M.); 5. E. pertinax Scop. (Kn.); 

 6. E. sepulcralis Z. (H. M.) ; 7. E. tenax Z. (Kn., H. M.) ; 8. Rhingia rostrata Z. 

 (H. M.); 9. Syrphus balteatus Beg. (Kn.) ; all po-dvg. C. Hymenoptera. Apidae: 

 10. Apis mellifica Z., po-cltg. (Kn., H. M.); 11. Halictus cylindricus F. 5 (Kn.); 

 1 2. H. sexnotatus K. j, po-cltg. (H. M.) ; 13. Prosopis signata Pz. $ 5, po-cltg. (H. M.). 



In the Alps Herm. Miiller also saw 4 flies, 3 beetles, 3 Hymenoptera. 



Loew observed the following in the Berlin Botanic Garden. A. Coleoptera. 

 Scarabaeidae-. 1. Cetonia aurata Z., devouring the anthers. B. Diptera. Syrphidae: 

 2. Syritta pipiens Z., po-dvg. C. Hymenoptera. Apidae: 3. Apis mellifica Z., 

 po-cltg. 



9. T. alpinum L. A pollen flower. The stamens projecting far out of the 

 pendulous flowers indicate that the plant is anemophilous. According to Lindman 

 the stigmas mature before the stamens, but remain in a receptive condition during 

 the dehiscence of the anthers. According to Ekstam, the flowers are protogynous- 

 homogamous in Nova Zemlia. According to Kerner, the stigmas of this species 

 are at first concealed under the sepals: but after the sepals have fallen away they 

 may be geitonogamously pollinated by neighbouring flowers. The same is true of 



10. T. flavum L. (Herm. Miiller, Fertilisation,' p. 70 ; MacLeod, ' Bot. Jaarb. 

 Dodonaea,' Ghent, vi, 1894; Schulz, 'Beitrage/ II, p. 2.) According to Warnstorf 

 (Verh. bot. Ver., Berlin, xxxvii, 1896) the flowers are slightly protogynous to homo- 

 gamous. The pollen is yellow, polyhedral, smooth, about 25-30 /x in diameter. 



Visitors. I observed the following in the gardens at Kiel. Apis mellifica 

 Z. $ , and Bombus lapidarius Z.; po-cltg. Hermann Miiller also observed the former 

 in the Lippe meadows, near Lippstadt, as well as a number of pollen-devouring 

 Diptera: (a) Syrphidae: 1. Eristalis arbustorum Z.; 2. E. nemorum Z.; 3. E. tenax 

 Z.; 4. E. sepulcralis Z.; 5. Syritta pipiens Z. (b) Muscidae: 6. Pollenia vespillo F. 



11. T. minus L. (Herm. Miiller, 'Weit. Beob.,' I, pp. 312-13; Kerner, 'Nat. 

 Hist. PI.,' Eng. Ed. 1, II; Schulz, 'Beitrage/ II, p. 2 ; Knuth, ' Bliitenbiol. Beob. 

 a. d. Ins. Riigen.') The filaments which are narrowed at the base project loosely 

 from the nectarless flowers, and are moved by every breath of wind. The plant is 

 therefore to be regarded as anemophilous. Owing to the sulphur-yellow colour of 

 the stamens, however, the flowers are very conspicuous, so that insects now 



