POLLEN PROTECTION 281 



found in the Alpenroses, the Primulas and Androsaces, 

 the Butterworts, Violets, and Monkshoods. 



More rarely the stamens are never exposed at all 

 to the weather. In the Globe-flower (p. 207), the 

 sepals form an arched roof over the stamens, while 

 in the flowers of the Pea family (Leguminosae) and 

 in the Box-leaved Polygala (p. 253), the stamens 

 remain enclosed in the petals. 



But in other plants where the flowers are held 

 with their stamens freely exposed to the weather, 

 special contrivances exist to protect the pollen. We 

 have seen how, in the case of the Carline Thistle 

 (p. 125), the bracts of the flower-head curve up over 

 it in bad weather. The flowers of the Anemones, 

 Gentians, Crocus, Colchicum, and others close entirely. 

 In other plants, such as the Common Daisy and the 

 Jacob's Ladder (p. 151), the flower-stalks curve at 

 night and in bad weather, so that the flowers, instead 

 of pointing upwards, nod towards the soil. Other 

 plants in which the stamens are freely exposed, such 

 as the Thalictrums, the Plantains, the Globularias, 

 and the Lady's Mantles (Alchemilla), meet the 

 difficulty by simply closing the anthers and ceasing 

 tp emit pollen until a more favourable season. The 

 anthers of Thesium alpinum, Linn., are said to close 

 within thirty seconds of their being moistened. 



It is obvious that the heavy night dews of the Alps 

 must have an effect similar to that of a slight shower of 

 rain, as regards danger to the pollen. Hence, most of 

 the types of movement mentioned above are normally 



