ONAGRARIEAE 447 



the four long (antisepalous) stamens being (in some flowers) at the same level as, 

 but remote from, the stigmas, which by this time have become receptive. The 

 anthers of the four short stamens are |— i mm. below the stigmas, though not so 

 far away from them as the others. Automatic self-pollination is therefore im- 

 possible. Insects can effect cross- and self-pollination with equal facility. 



In other flowers, the anthers of the four long stamens cling to the style after 

 discharging their pollen. The filaments elongate later on, and, as the anthers are 

 not set free from the style, are subjected to a stress which forces them to bend 

 inwards. They sometimes remain in this condition till the end of anthesis, so that 

 crossing by insects is almost impossible. In other cases they gradually free them- 

 selves from the style, on which the greater part of the pollen is left behind. When 

 the flower closes the anthers are pressed against the stigmas, so that autogamy 

 is inevitable. 



Visitors. — MacLeod saw the butterfly Pieris napi L., skg. 



1052. E. latifolium L. (Warming, ' Bestovningsmaade af nogle gronlandsk. 

 Blomster,' p. 143.) — This species is native to high northern latitudes. Warming 

 states that the large flowers vary from slightly protandrous to slightly protogynous. 

 The remarkably short style is bent down, bringing the stigmas below the anthers, 

 so that autogamy may result from the fall of pollen. Should this take place, however, 

 it does not result in autocarpy. There is a large amount of vegetative reproduction 

 by means of offsets. 



Several sub-species have been found in Greenland, where blossoms of pure 

 white colour are rare. Vanhoffen states that as a rule the flowers are feebly 

 protandrous, but two stocks bearing strongly protandrous ones were observed 

 (Abromeit, ' Bot. Ergeb. von Drygalski's Gronlandsexped.,' p. 13). 



There would appear to be insect visitors in Greenland, for a hybrid (=E. 

 ambiguum Fries) has been found at Disko between this species and E. angusti- 

 folium. 



1053. E. lactifolium Haussk. (Abromeit, op. cit., pp. 12-13.) — This arctic 

 species ranges south to Scandinavia and Lapland. It bears small whitish flowers, 

 and reproduces vegetatively by means of short offsets arranged in a rosette-like 

 manner. It has been observed in Greenland by Vanhoffen and K. Rosenvinge. 



301. Lopezia Cav. 



Flowers markedly protandrous, often with an explosive stamen. 



According to Delpino (' Ult. oss.,' II, pp. 124-6), there are two pseudo- 

 nectaries at the knee-like bend of the two upper petals. These shine like drops 

 of nectar, but are dry in reality {cf. Parnassia, p. 413). The true secreting nectary 

 is at the base of the two stamens, of which one is sterile and specialized. {Vide 

 infra) 



1054. L. coronata Andr. (Hildebrand, Bot. Ztg., Leipzig, xxiv, 1866, p. 76.) — 

 One of the original two stamens in this species is modified into a stalked spoon- 

 shaped staminode, the two halves of which at first surround the anther of the normal 

 stamen, and project horizontally from the flower. As the stalk of the spoon is 



