II ERICACE^ 263 



because each cell, just where the opening is situated, 

 rests against the next anther cell, and the series of 

 anthers thus form a circle surrounding the pistil and 

 not far from the centre of the bell. Each anther cell 

 also sends, out a long process (pr), which thus form a 

 series of spokes standing out from the circle of anthers. 

 Under these circumstances, a bee endeavouring to suck 

 the honey from the nectary cannot fail, firstly, to bring 

 its head in contact with the viscid stigma (Fig. 164, st), 

 and thus to deposit upon it any pollen derived from a 

 previous visit ; and, secondly, in thrusting its proboscis 

 up the bell it inevitably comes in contact with one of 

 the processes (pr), which then acts like a lever and dis- 

 locates the whole chain of anther cells, when a show:er 

 of pollen falls on to its head. 



E. cinerea (our Common Heath). — The arrangement 

 of the flower agrees with that of J^. Tetralix ; the leaves 

 are, however, glabrous, and in whorls of three. 



E. carnea. — In this species — which is a native of 

 Ireland, but not of Great Britain — the plant is, ren- 

 dered additionally conspicuous by the redness of the 

 stem. The anthers have no processes, and project a 

 little beyond the corolla. The style is still longer, so 

 that insects visiting the flower must touch the stigma 

 first, and then the anthers. It cannot fertilise itself, 

 as the stigma is not widened out, but is, as it were, 

 cut sharp ofi". The pollen grains are united in fours. 

 From the narrowness of the entrance H. Miiller looks 

 on this as a butterfly flower. The bright red colour 

 also points in this direction. He found it, in fact, 

 almost exclusively visited by Vanessa cardui. The 

 flower-buds are fully formed in the summer for the suc- 

 ceeding year. 



Callttna 



Calluna vulgaris (Ling). — This species was formerly 

 described as a species of Erica, but is now regarded, 

 and, as it seems to me, correctly, as a distinct genus. 



