PARTIIKNOGENKSIS 279 



Lam'ium amplexlcaulc, Linn.), which aro difTercntly 

 constructed from the normal tlowers borne by the same 

 plants. 



The extraordinary phenomenon called partheno- 

 genesis, which sometimes occurs both in plants and 

 animals, in which the ovule is able to develop 

 normally without having been fertilised at all by the 

 male sperm produced by the pollen grain, has so far 

 only been observed in the Alps in the case 'of certain 

 species of Lady's Mantle, genus Alchemilla (natural 

 order Rosacea?, the Kosc family). Another case 

 is known in the Arctic regions — namely, Antennaria 

 alpina, Gi\}rtner { = Gnaphalium alpinum, Linn.), a 

 plant nearly related to the Swiss Everlastings (see 

 p. 21). Not only are no male tlowers of this species 

 known in the Arctic regions, but the female flowers, 

 which in this genus are borne on different plants 

 to the male, regularly set their seed without having 

 been pollinated at all. 



Before leaving this subject, wx may note that in 

 the tropics certain flowers are fertilised by animals 

 other than insects, such as bats, humming, and 

 honey-sucking birds, snails, and slugs. 



The Protection of Pollen. 

 Everyone who has travelled in the .Vlps has been 

 impressed, often in a disagreeable manner, by one fact 

 — namely, the variableness of the weather. In the 

 mountains the changes in the condition of the weather 

 are often extremely rapid. For instance, the early 



