THE BOX-LEAVED POLYGALA 251 



The ovary in the fruit becomes a nut, and remains 

 enclosed in the two little leaves on the flower-stalk, 

 just below the flower, which at this stage increase 

 greatly in size. They are covered with glandular 

 hairs, which catch in the furry coat of any passing 

 animal, and thus the fruits are distributed to a 

 distance from the parent plant. 



The Box-leaved Polygala. 



We are all familiar with our little Common Milk- 

 wort {Polygala vulgaris, Linn., natural order Poly- 

 galaceae, the Milkwort family), which, with other 

 Alpine species, is frequent also in Switzerland. But 

 in the Alpine woods and forests we often find another 

 species, the Box-leaved Polygala {Polygala chamce- 

 buxus, Linn.) (Plate XL VI., Fig. 1), forming httle 

 carpet-like patches on the rocks. The whole habit 

 or build of this plant is quite unlike that of the 

 Common Milkwort. It is a low creeping shrub, with 

 leathery evergreen leaves, like those of the Box 

 {Buxus), and quite unUke the typical shade-leaves of 

 most Alpine forest plants. There is a good reason 

 for this difference. The fact is that the Box-leaved 

 Polygala is an immigrant from the Mediterranean 

 flora, like the Alpine Heath {Erica carnea, Linn.) and 

 Biseutella laevigata, Linn., among other southern 

 plants which have successfully invaded the Alps. It 

 has retained several of the characteristic features of 

 the subtropical flora of Southern Europe, such as, for 

 instance, the evergreen leaves and the shrubby habit. 



