68 TYPICAL FLOWERS OF ALPINE PASTURES 



level of the soil. For this reason it is often over- 

 looked. 



The Oxlip is a good plant on which to observe 

 the very interesting adaptation to cross-fertilisation 

 known as heterostylism. If we slit open with a 

 needle or pin the corollas of a number of flowers, we 

 shall be able to distinguish two types. One set will 



Fig. V. — Diagrammatic Views of the Heterostyled Flowers 

 of a Primula. 



1. Flower with short style and high stamens. 



2. Flower with long style and low stamens. 



be found to possess a long style (the prolongation of 

 the ovary) extending almost to the throat of the 

 corolla tube (Text-fig. V., 2), and five short stamens, 

 seated on the corolla itself, near the base of the 

 corolla tube. 



Other flowers will be found to be tlie exact 

 opposite (Text-fig. V., 1). The style here is very short 

 and the stamens are very long, and occupy the same 



