CRUCIFERAE 



119 



of each of the four long ones. The stamens are at the same level as the stigma, and 

 mature simultaneously. They regularly effect automatic self-pollination, which is 

 effective, according to Comes (' Stud. s. impoll. i. ale. piante '). Warnstorf says that 

 the anthers of the two stamens are pressed against the mature stigma by two sepals 

 when the flower opens. 



295. L. campestre L.— According to Kirchner ('Beitrage,' pp. 28-9), the 

 very small white flowers are only 2 mm. in diameter when expanded. On either 

 side of the base of each short stamen there is a small green nectary (VelenovskJ' 

 figures 6 nectaries). The six anthers — which mature simultaneously — turn their 

 dehisced sides towards the stigma. The sepals when they wither close together 

 in such a way as to press all the stamens against the stigma, thus effecting automatic 

 self-pollination, which is probably indispensable. Kerner says that this species is 

 slightly protogynous. 



296. L. graminifolium L. — 



Visitors. — Schletterer observed the following at Pola. — 



Hymenoptera. {a) Apidae: i. Prosopis genalis TXotoj (=P. confusa /'(StjA). 

 (*^) Ichneunionidae: 2. Amblyteles litigiosus Wesm. (c) Sphegidae: 3. Pemphredon 

 unicolor F. 



89. Hutchinsia R. Br. 



Small, white, homogamous or protogynous flowers, with half-concealed nectar. 

 Four nectaries. 



297. H. alpina R. Br. (Herm. Muller, ' Alpenblumen,' p. 150; Schulz, 

 'Beitrage,' II, p. 17.) — Hermann Muller describes the flowers as protogynous, with 

 persistent stigmas. Only some of the plants he examined — at Albula Hospice — were 

 capable of automatic self-pollination : in these the four long stamens reached the 

 stigma. A. Schulz describes the flowers — for the South Tyrol — as homogamous 

 or nearly so, and automatically self-pollinated by contact of the anthers of the long 

 stamens with the stigma. Kerner states that autogamy takes place as in Schievereckia 

 (see p. 107). 



90. Capsella Vent. 



Small, white, homogamous flowers with half-concealed nectar. Four nectaries. 



298. C. Bursa-pastoris Moench. (Herm. Muller, ' FertiHsation,' p. no, ' Weit. 

 Beob.,' II, p. 204 ; Kirchner, 'Flora v. Stuttgart,' p. 311 ; Knuth, 'Bl. u. Insekt. a. d. 

 nordfr. Ins.,' pp. 31, 149; Warnstorf, Verh. bot. Ver., Berhn, xxxviii, 1896.) — The 

 four nectaries are at the sides of the short stamens. All the anthers remain turned 

 towards the stigma, those of the four long stamens being at the same level, and so 

 near it that automatic self-pollination — which is effective — regularly takes place. 

 Insect visitors may effect either cross- or self-pollination. 



Breitenbach observed relatively large female flowers in addition to the herma- 

 phrodite ones (Justs bot. Jahresber., Leipzig, xii (1884), 1886, p. 676). 



Willis (Proc. Phil. Soc, Cambridge, 1893) also observed gynomonoecism and 

 gynodioecism in England. Burkill's investigations (' Fertlsn. of spring fls.') prove 

 that cold produces gynodioecism and gynomonoecism in this species. Plants that 



