PRIMULACEAE 



63 



The narrowness of the corolla-tube protects the nectar from rain-drops, which are 

 unable to displace the air. 



Kerner states that many species are heterostylous. 



1803. A. septentrionalis L. (Herm. Miiller, ' Alpenblumen,' p. 358 ; Kerner, 

 *Nat. Hist. PI.,' Eng. Ed. i, II, p. 341.) The white flowers of this species are 

 only 6 mm. in diameter, {C/. Fig. 237.) Kerner says that automatic self- 

 pollination is ultimately ef- 

 fected by contact of the 

 anthers and stigma. 



Visitors. Herm. Miiller 

 observed anEmpid, aSyrphid, 

 and 3 Muscids. 



1804. A.Chamaejasme 

 WiUd. (Herm. Muller, 'Al- 

 penblumen,' pp. 358-9.) In 

 this species the flowers are 

 7-8 mm. in diameter. The 

 nectar-guide is at first yellow 

 in colour, but becomes car- 

 mine-red after pollination has 

 been effected. Should insect- 

 visits fail, the latter takes place automatically by the fall of pollen. {C/. Fig. 238.) 



Visitors. Herm. Muller observed 15 flies, 4 Lepidoptera, and a bee. 



Fig. 237. Androsau septentrionalis, L. (after Herm. Muller). 

 A. Flower seen directly from above. B. Do. in longitudinal section. 

 C. Pistil seen obliquely from above (x 7). 



Fig. 238. Androsace Chamaejasme, Witld. (after Herm. Muller). A. Flower seen directly from 

 above. B. Do. in longitudinal section. C. Older pistil seen obliquely from above (x 7). D. Younger 

 pistil. 



1805. A. obtusifolia All. (Herm. Muller, 'Alpenblumen,' p. 360.) The white 

 flowers of this species are more than 8 mm. in diameter. Autogamy is easily effected. 



Visitors. Herm. Miiller observed 10 flies and 3 Lepidoptera. 



1806. A. alpina Lam. (=A. glacialis Hoppe). (Herm. Miiller, 'Alpenblumen,' 

 p. 360.) The white or rose-red flowers of this species are 5 mm. broad, and possess 

 nectar-guides. They are homogamous, and autogamy takes place should insect- 

 visits fail. 



