CRUCIFERAE in 



Hist. PI.,' Eng. Ed. i, II; Knuth, ' Bloemenbiol. Bijdragen.') There are muriform 

 nectaries at the bases of the stamens in the fragrant flowers, but the secretion is very 

 scanty. All the anthers dehisce introrsely ; those of the long stamens are at the same 

 level as the stigma, which matures simultaneously. This being in the entrance to the 

 flower, cross-pollination is likely to be effected by insect visitors. Self-pollination 

 may also easily occur, though Kerner says that it is almost or entirely ineffective. 

 According to Warnstorf, the flowers are protogynous, and the stigmatic papillae 

 mature before anthesis. The same authority states that all the stamens project 

 beyond the stigma. The pollen-grains are yellowish, ellipsoidal, tuberculated, on an 

 average 37-43 /j. long and 15-19 //. broad. 



Visitors. Hermann Miiller (H. M.) and myself (Kn.) have observed the 

 following. 



A. Coleoptera. (a) Nitidulidae: 1. Meligethes sp. in immense numbers (Kn., 

 H. M.). (b) Telephoridae : 2. Malachius bipustulatus L., dvg. the anthers (H. M.). 

 B. Diptera. (a) Bibionidae : 3. Bibio hortulanus Z., searching for nectar (?) (H. M.). 

 (b) Empidae: 4. Empis punctata F., skg. (H. M.). (c) Muscidae: 5. Scatophaga 

 merdaria F., skg. (H. M.); 6. Sepsis sp. (Kn.). (d) Syrphidae: 7. Eristalis sp., 

 skg. and po-dvg. (Kn.); 8. Syritta pipiens ., ditto (H. M., Kn.); 9. Syrphus 

 balteatus Deg. ditto (Kn.). C. Hymenoptera. (a) Apidae: 10. Andrena albicans 

 Mull. 5, ditto (H. M.); n. Halictus levis K. 5, skg. (H. M.); 12. H. zonulus Sm. 5, 

 skg. (H. M.). (b) Ichneumonidae : 13. Several sp., searching for nectar (H. M.). 





270. C. officinalis L. (Knuth, ' Bl. u. Insekt. a. d. nordfr. Ins.,' pp. 29, 149.) 

 The flowers are 8-10 mm. in diameter. Those I examined appeared to have 

 no nectaries. Burkill (' Fertlsn. of spring fls.'), on the other hand, says that on the 

 Yorkshire coast there are four well-marked nectaries at the base of the flower. The 

 anthers of the four long stamens are at the same level as the stigma which matures 

 simultaneously and at first somewhat turned away from it. The anthers of the short 

 stamens dehisce rather later, and in early anthesis are lower than the stigma, though 

 subsequently they reach its level. Automatic self-pollination is therefore quite 

 possible. Either cross-pollination or self-pollination may be effected by insect visitors 

 while collecting pollen, or boring in the base of the flower for sap. 



Andersson and Hesselman state (' Bidrag till Kanned. om Spetsbergens o. Beeren 

 Eil. Karlvaxtflora,' pp. 34-40) that the diverse varieties included by Gelert in this 

 strongly polymorphous species as /?. groenlandica (L.) Gel., y. oblongifolia (DC.) 

 Gel., and 8. arctica (Schlecht.) Gel. bloom in Spitzbergen from early spring to 

 autumn, fruits being set from the end of July till autumn. The plant flowers 

 abundantly on Beeren Island in mid-July. According to Ekstam the flowers of 

 C. arctica Schlecht. have a diameter of 3-4 mm. and are apparently protogynous- 

 homogamous. Some of them are female. 



Visitors. I have observed various flies Syrphidae and Muscidae and beetles 

 Meligethes. Loew saw the honey-bee in the Berlin Botanic Garden. Burkill 

 (' Fertlsn. of spring fls.') noticed the following on the Yorkshire coast. 



A. Coleoptera. Nitidulidae: 1. Meligethes picipes Sturm, skg. B. Diptera. 

 Muscidae : 2. Coelopa sp., skg. ; 3. Hylemyia sp., skg. ; 4. Drosophila graminum Fall., 

 skg. ; 5. Scatophaga stercoraria L., skg. and po-dvg. ; 6. another small Muscid. 

 C. Hymenoptera. Ichneumonidae: 7. Ichneumon sp., skg. 



