104 ANGIOSPERMAEDICOTYLEDONES 



the petals along with the sepals form a tube \-x\ mm. wide and 15 mm. long 

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

 collects in the bottom of the tube just mentioned. Cross-pollination predominate 

 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 usua 

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

 The flowers examined by Kirchner (Bot. Centralbl., Cassel, lxix, 1897, P* 2 > not 

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



71. Alyssum Tourn. 



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

 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. 1, II; Knuth, ' Bloemenbiol. Bijdragen.') The small flowers- 

 1-5-2 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 pets 

 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 protogyn) 

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

 the stamens incline towards the stigma towards the end of anthesis, and autogamj 

 results. 



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

 Herm. Miiller ('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. 1, II; Schulz, 

 'Beitrage,' II, p. 15.) The homogamous yellow 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 the 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 : 1 . Dasytes plumbeus Mull., 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 ., freq., skg. and po-dvg. C. Hymenoptera. (a) Apidae : 6. Halictus 

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

 $, in large numbers, skg. (6) Sphegtdae : 9. Cerceris rybiensis Z., not infrequent, skg. 



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

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

 neglecta Dours J. 



