630 



Professor L. C. 3Iiall, 



[Feb. 18, 



keep tlio roots comparatively dry ; others direct the water down the 

 branches and stem to the roots. Bilberry is one of the latter sort. 

 The rounded leaves slope downwards towards the leaf stalk, and 



from the base of every leaf 

 stalk starts a pair of grooves, 

 which are sunk in the sur- 

 face of the stem. A light 

 summer shower is economised 

 by the guiding of the drops 

 towards the roots. Bilberry 

 abounds on the loose and 

 sandy tracts of the moor, and 

 especially on its verges ; it 

 is seldom found upon a deep 

 bed of peat. 



There is a moorland plant 

 which may be said to mimic 

 the heaths, as a Euphorbia 

 mimics a Cactus, or Sarra- 

 cenia a Nepenthes. Simi- 

 larity of habit has brought 

 about similarity of structure. 

 The plant I mean is the 

 Crowberry, which is so like 

 a true heath in its foliage 

 and manner of growth, that 

 even the botanists, who did 

 not fail to remark that the 

 flowers are altogether dif- 

 ferent, long tried to bring 

 the crowberry and the heaths 

 as near together in their 

 systems as they could . Crow- 

 berry has the long, dry, wiry 

 stems, the small, narrow, 

 rolled, clustered, evergreen 

 leaves of a true heath. The 

 leaf margins are turned back 

 till they almost meet, and 

 the narrow cleft between 

 them is obstructed by close- 

 set hairs, so that the trans- 

 piring surface is effectually 

 sheltered. Crowberry is a 

 peat-loving shrub, and is often found with ling and other heaths in 

 the heart of the moor. The berries are a favourite food of birds, 

 which helj) to disseminate the species. Crowberry has an un- 

 commonly wide distribution, not only in the Arctic and Alpine 



Fig. 7. — Crowberry (Empetrum nigrum'). 

 A staminate branch, slightly enlarged; 

 a, part of a pistillate branch ; 6, one sta- 

 minate flower ; c, one pistillate flower. 



