632 ANGIOSPERMAE—DJCOTYLEDONES 



of September, and fruiting specimens have been observed (by Nathorst, 17. 8. '82. 

 The pollen is abundant, and normally developed (Andersson and Hesselman, 

 ' Bidrag till Kanned. om Spetsbergens o. Beeren EiL Karlvaxtflora,' p. 10). 



1494- A. Chamissonis Less. — 



Visitors. — Loew observed 2 Syrphids (Eristalis aeneus Scop., and E. tenax Z.) 

 and 2 bees (Heriades truncorum L. 5, po-cltg. ; and Megachile centuncularis L. 5, do.) 

 in the Berlin Botanic Garden. 



462. Cacalia L. 



1495. C. hastata L. — The heads of this species exhale a strong odour of 

 honey. 



Visitors. — Knuth observed the following (12.9. '97) in the Kiel Botanic Garden; 

 all (except 5 and 7) very freq., and all skg. (' Bliitenbiol. Notizen'). — 



A. Diptera. Syrphidae: i . Eristalis intricarius Z. ; 2. E. tenax Z. ; 3. Syrphus 

 coxoWatF.; 4. S. ribesii Z. ; 5. Volucella pellucensZ., occasional. B. Hymenoptera. 

 Apidae : 6. Apis mellifica Z. 5 J 7- Bombus agrorum F. 5, occasional ; 8. B. lapidarius 

 Z. $: 9. B. terrester Z. 5. C. Lepidoptera. Rhopalocera: 10. Vanessa ioZ. ; 



II. V. urticae Z. 



463. Senecio L. 



Literature. — Hildebrand, ' tj. d. Geschlechtsverhalt. b. d. Compositen.'pp. 27-8, 

 Taf. II, Figs. 29-36 (S. populifolius). 



Ray-florets female, ligulate, yellow in colour, sometimes wanting; disk-florets 

 hermaphrodite, tubular, yellow. Stylar branches with an apical bundle of sweeping- 

 hairs, quite covered with stigmatic papillae internally and marginally. 



1496. S. vulgaris L. (Herm. Mtiller, 'Fertilisation,' p. 336, 'Weit. Beob.,' 



III, p. 90 ; Knuth,' Bl. u. Insekt. a. d. nordfr. Ins.,' p. 94, ' Bloemenbiol. Bijdragen.') — 

 Ligulate ray-florets are wanting in this species. Hermann Miiller says that there are 

 60-80 florets in a single head, with corolla-tubes 3^-4 mm. in length and bells 

 i-i^ mm. long. Nectar ascends into the bell and is therefore very easily accessible. 

 Owing to the small size of the heads (only 4 mm. in diameter) and the fact that the 

 plant is not very conspicuous, insect-visits are few. The pollen-grains brushed out of 

 the anther-cylinder by the sweeping-hairs which form a tuft at the end of the stylar 

 branches, partly remain clinging to the marginal papillae when the branches diverge, 

 and partly fall on their stigmatic inner surfaces. It follows that automatic self- 

 pollination regularly takes place, and this is certainly effective. Bateson found, 

 however, that plants resulting from cross-pollination were larger and more fertile than 

 those produced by autogamy. 



Visitors. — The following were recorded by the observers, and for the localities 

 stated. — 



Knuth, on one occasion, a hover-fly (Melanostoma mellina Z.) po-dvg. Herm. 

 Miiller, during a period of 1 5 years, not infrequently saw a hover-fly (Syritta pipiens Z.) 

 and a bug (Pyrrhocoris apterus Z., skg.). Buddeberg (Nassau), 2 bees (Halictus 

 morio F. 5, skg. ; and Heriades truncorum Z. $, do.). Verhoeff (Norderney), the 

 hover-fly Syritta pipiens Z. MacLeod (Flanders), 4 Hymenoptera, 5 Syrphidae, 

 4 Muscidae, and a Lepidopterid (Bot. Jaarb. Dodonaea, Ghent, v, 1893, pp. 427-8, 

 vi, 1894, p. 374). Scott-Elliot (Dumfriesshire), a Muscid ('Flora of Dumfriesshire,' 

 p. 97). Burkill (Yorkshire coast), a Muscid (Anthomyia sp.) (' Fertlsn. of Spring Fls.'). 



