EUPHORBIACE.E^EMFETRACEJi; 



353 



above. The former have one bract, the latter three. 

 The clusters are slightly protogynous. The pollen, like 

 that of wind flowers generally, is dry and dusty, but 

 the hive bee, having separated the pollen from the 

 anther, moistens it with nectar from its mouth, and 

 then brushes it on to its hind legs. The leaves are 

 evergreen, and well protected against extremes of 

 temperature and drought. The epidermis is thick, the 

 stomata are sunk, and there are no less than four rows 

 of palisade cells. The polished surface, which occurs 

 in several other evergreen species, is perhaps a provision 

 to throw off snow. 



EMPETEACEiE 



Empetrum (Crowberry) 



Generally dioecious. Warming and Knuth consider 

 them as wind flowers. Lindman regards them as 

 fertilised by insects, especially flies. They have nectar, 

 but very little. 



Fig. 227. — Transverse section of leaf of Empetrum. Mnch enlarged, a, upper 

 epidermis ; J, lower epidermis ; s, stoma. 



E. nigrum. — The male flowers are rose, the female 

 purple. The pistil is short, with 6-9 diverging black 

 shining stigmas. Besides the dicBcious, Lindman found 

 some protandrous complete flowers. 



The leaves are evergreen and conform to the heath 



2 A 



