104 ANGIOSPERMAE—DICOTYLEDONES 



the petals along with the sepals form a tube i-i-| mm. wide and 15 mm. long. 

 At the bases of the two short stamens there are four nectaries, of which the secretion 

 collects in the bottom of the tube just mentioned. Cross-poUination predominates, 

 for the stigma projects somewhat beyond the anthers of the four long stamens — 

 which are in the entrance of the flower — so that automatic self-pollination is usually 

 impossible. The two outer stamens are sometimes as long as the four inner ones. 

 The flowers examined by Kirchner (Bot. Centralbl., Cassel, Ixix, 1897, P- 2°> note) 

 were odourless; they exhibited slight protogyny, and their diameter was 15-22 mm. 



71. Alyssum Toum. 



Flowers rather small, yellow, homogamous to protogynous, with half-concealed 

 nectar. Usually four nectaries. There is sometimes no nectar. 



243. A. calycinum L. (Kirchner, ' Flora v. Stuttgart,' p. 304 ; Kerner, ' Nat. 

 Hist. PI.,' Eng. Ed. i, II; Knuth, ' Bloemenbiol. Bijdragen.') — The small flowers — 

 I -5— 2 mm. in diameter — are devoid of nectar; they are at first bright yellow, but 

 subsequently colourless. The erect sepals closely ensheath the claws of the petals. 

 The anthers dehisce introrsely, and as those of the short stamens are at the same 

 level as the stigma, while those of the long ones project beyond it, automatic 

 self-pollination is inevitable. Kerner says that there is at first slight protogyny, 

 so that in the early stage insect-visits must effect cross-pollination, but failing these 

 the stamens incUne towards the stigma towards the end of anthesis, and autogamy 

 results. 



Visitors. — In the Kiel Botanic Garden I have observed Syritta pipiens L. skg. ; 

 Herm. MtiUer (' Weit. Beob.,' I, p. 327) — in Thuringia — saw one of the Conopidae — 

 Myopa testacea L. — skg. 



244. A. montanum L. (Kerner, 'Nat. Hist. PI.,' Eng. Ed. i, II; Schulz, 

 ' Beitrage,' II, p. 15.) — The homogamous 3'ellow flowers are rather small, and smell 

 like honey. There are four functional nectaries, two in the angle at the bases of 

 the short stamens, and two between the long stamens of each pair. The anthers are 

 usually at the same level as the stigma, which matures at the same time. In 

 fine weather the petals and stamens spread out to some extent, when cross-pollination 

 is likely to result from insect-visits. In dull weather and at night ihe petals and 

 stamens are closely applied to the pistil, so that automatic self-pollination must 

 result. Kerner says that the conspicuousness of the inflorescence is greatly enhanced 

 by growth of the petals after the flowers have opened. 



Visitors. — Schulz noticed flies. Hermann Miiller observed the following in 

 his garden. — 



A. Coleoptera. Telephoridae : i . Dasytes plumbeus 7I/«7/., freq. B. Diptera. 

 [a) Muscidae: 2. Sp. of Anthomyia, freq., skg.; 3. Lucilia cornicina F., skg. per- 

 sistently, (b) Syrphidae: 4. Eristalis sepulcralis Z., in large numbers, skg. ; 5. Syritta 

 pipiens L., freq., skg. and po-dvg. C. Hymenoptera. {a) Apidae : 6. Halictus 

 niiidiusculus K. 5, freq., skg. and po-cltg. ; 7. Nomada ruficornis Z., skg. ; 8. Prosopis 

 J, in large numbers, skg. {b) Sphegidae : 9. Cerceris rybiensis Z., not infrequent, skg. 



Friese saw in Hungary the rare species Andrena tscheki Alor. (=A. nigrifrons 

 Sm.). Ducke records from Trieste, Andrena tscheki Afor. 5, and A. (Biareolina) 

 neglecta Dours $. 



