6l2 



AN GIOSPERMAE DICOTYLEDON ES 



turning their stigmatic surfaces upwards, and protrude a little from the bell, while the 

 empty anthers become somewhat retracted. The disk-florets are usually surrounded 

 by 5 ray-florets with large corolla-limbs and no stamens ; these increase the diameter 

 of the head to 9-10 mm. 



Failing insect-visits, automatic self-pollination is effected in the disk-florets by 

 the fall of pollen from the sweeping-hairs on the outspread stigmatic papillae. 



Gynodioecism is also said to occur occasionally. 



Fig. 199. Achillea Mille/olium, L. (after Herm. Mailer), (i) A single head, seen from above i 

 a, stigmas of purely female ray-florets; b, do. of disk-florets in the second stage; c, anther-cylinder of 

 disk-floret in the first stage; d, bud nearly ready to open. (2) Single disk-floret in the act of opening, 



seen in longitudinal section: e, ovary; f, nectary; g y style; h, corolla-tube; 1, filaments; k, stylar 

 branches ; /, tip of the style, with sweeping-hairs ; *, anther-cylinder ; , throat of corolla ; o, valves 

 closing the anther-cylinder. (3) Disk-floret (with bract) somewhat more advanced ; pollen is issuing 

 from the anther-cylinder. (4) Older disk-floret ; the diverging stylar branches protrude, and the 



anther-cylinder is retracted into the corolla. (5) Tip of the style of a disk-floret in the first (male) stage : 

 i', stigmatic papillae ; /, sweeping-hairs ; />, pollen-grains. 



Chrysanthemum Leucati/hemum, L. (6) Disk-floret in the first (male) stage : />, pollen. (7) Do., 

 in the second (female) stage. (8) Tip of a stylar branch, seen from within (X 60): k', stigmatic 

 papillae ; /, sweeping-hairs. 



Visitors. I observed the following in Schleswig-Holstein (S.-H.), and on 

 higher part of Helgoland (H.). 



A. Coleoptera. All po-dvg. (a) Curculiontdae: i. Apion marchicum Hbst 

 (S.-H.). (b) Nitidulidae : 2. Meligethes sp. (S.-H.). (c) Telephoridae \ 3. Cantharis 

 fulva Scop. (S.-H.). B. Diptera. (a) Muscidae : all skg. : 4. Anthomyia sp. (S.-H.) ; 

 5. Aricia incana Wted. 5 (S.-H.) ; 6. Dolichopus plumipes Scop. (S.-H.) ; 7. Leucostoma 

 aenescens Zelt. (S.-H.) ; 8. Lucilia caesar Z. (S.-H.) ; 9. Musca corvina F. (S.-H.) ; 

 10. Nemotelus uliginosus L. (S.-H.); 11. Oliviera lateralis F. t skg. (S.-H.); 

 12. Onesia sp. (S.-H.); 13. Pollenia sp. (S.-H.); 14. Sarcophaga camaria L. 

 (S.-H.); 15. S. striata Fabr. (S.-H.); 16. Scatophaga lutaria F. (S.-H.); 17. S. 

 merdaria F. (S.-H.); 18. S. stercoraria Z. (S.-H. and H.); 19. Spilogaster carbo- 





