II SAXIFEAGACE.E 199 



man in the Dovrefjeld, tliey are protogynous. In the 

 absence of insect visits they fertilise themselves. 



S. stellaris. — This species also is recorded in some 

 districts as protandrous, in others as homogamous, and 

 elsewhere again as protogynous. 



S. tridactylites. — According to Sprengel this species 

 is protandrous, while H. MilUer describes it as proto- 

 gynous. The leaves have sticky glandular hairs, which 

 often capture small insects. The glands are absorbent, 

 so that it is quite possible that the plant derives some 

 nourishment from them. 



S. umbrosa (London Pride). — ^In this species also the 

 peduncles and petioles of the leaves bear a certain number 

 of glandular hairs, and the flowers are thus protected 

 against creeping insects. 



Chrysosplenium 



The flowers are greenish or golden-yellow, and incon- 

 spicuous, with exposed honey, which is secreted by a 

 band surrounding the base of the pistil. The leaves 

 surrounding the flowers are often golden yellow, thus 

 making the flowers more conspicuous. We have two 

 species, one with a triangular stem and alternate leaves, 

 the other with a quadrangular stem and opposite leaves. 

 These two conditions evidently depend on one another, 

 but which is the determining factor ? Besides the com- 

 plete flowers, there are others with stamens only. 



C. alternifolium. — The flowers are homogamous, but 

 apparently with a tendency in some places to become 

 protogynous. The flowers and surrounding leaves are 

 arranged on a plane, which renders them more con- 

 spicuous, and also more convenient for small insects. 

 Small snails, especially Succinea, also appear to assist 

 in the fertilisation. 



C. oppositifolium. — The arrangement of the flowers 

 is similar, but they are protogynous. 



