ROSACEAE 365 



859. F. elatior Ehrh. (=F. moschata Duchesne). The mechanism of the 

 flowers of this species, according to Kirchner ('Flora v. Stuttgart,' p. 442), agrees 

 with that of F. vesca. Schulz (' Beitrage,' II, p. 187), observed andromonoecism 

 and androdioecism, rarely gynodioecism and gynomonoecism. The species is 

 sporadically purely dioecious, in some places there are only male-pleogamous or 

 feraale-pleogamous stocks, while elsewhere 10 % or more of the flowers are 

 hermaphrodite. 



Visitors. Herm. Muller observed beetles, a wasp, a Lepidopterid, a Bombylius, 

 and 4 hover-flies in the Alps (' Alpenblumen,' p. 216). Loew noticed a Syrphid 

 (Chrysogaster coemeteriorum Z.), skg., in the Berlin Botanic Garden. 



860. F. collina Ehrh. (=F. viridis Duchesne). The yellowish-white flowers 

 of this species are imperfectly dioecious ; pseudo-hermaphrodite plants usually pre- 

 dominate. Schulz ('Beitrage,' II, p. 187) observed androdioecism and gynodioe- 

 cism, and also andromonoecism and gynomonoecism. Kirchner (' Flora v. Stuttgart,' 

 p. 441) states that the male and female flowers differ in size; in the former the 

 stamens are twice as long as the group of carpels, in the latter the anthers (which do 

 not dehisce) are at the same level. 



Visitors. Loew observed 2 Syrphids (Eristalis nemorum Z., po-dvg., and E. 

 sepulcralis Z.) in the Berlin Botanic Garden. 



250. Comarum L. 



Dark purple-red protandrous flowers, with nectar half- or completely concealed 

 and secreted in the usual place. 



861. C. palustre L. (Knuth, ' Bl. u. Insekt. a. d. nordfr. Ins.,' pp. 67-8, 154, 

 'Weit. Beob. ii. Bl. u. Insekt. a. d. nordfr. Ins.,' p. 234.) The flowers of this species 

 are about 2^ cm. in diameter, and secrete abundant nectar from a green ridge-like 

 disk situated between the stamens and the carpels. The large sepals are dark 

 purple-red to almost brown internally, while the much smaller petals are rather 

 brighter in colour. The anthers dehisce laterally some time after the perianth has 

 unfolded. The stamens, which number about twenty and are in two whorls, are at 

 first erect, the inner anthers being above the carpels, so that pollen must fall upon 

 the stigmas. As these are still immature, however, such self-pollination is not 

 effective. After the anthers have fallen off, the filaments bend back towards the 

 perianth, leaving the space they occupied in the middle of the flower free for 

 the styles. These meanwhile increase in length, and their tips are beset with small 

 i-ellow papillae. It follows that insect-visits must effect crossing, while automatic 

 self-pollination is excluded, even when some of the pollen remains adhering to 

 the stigmas. 



After fertilization has been effected the broad sepals shut together above, and 

 with them the small (5 mm. long, 1^ mm. broad) pointed petals, so that the opening 

 of the flower is closed, and the less conspicuous reddish-green outer surfaces of the 

 sepals once more become visible (as in the bud). The epicalyx remains perpendi- 

 cular to the peduncle. Warnstorf describes the pollen-grains as yellowish in colour, 

 smooth, spherical, and 25-31 fi in diameter. 



