II COMPOSITiE 241 



The ray itself is broad and short. The list of insect 

 visitors is very long. H. Miiller observed over 120, 

 and others have been added since. The plant is some- 

 times glabrous, sometimes densely covered with white 

 woolly hairs. 



A. Ptarmica. — The flower-heads are larger than those 

 of A. Millefolium, but not so numerous. They appear 

 to be especially attractive to bees of the genus Prosopis. 

 The plant is nearly glabrous. 



DiOTIS 



D. maritima. — The plant is covered with a dense 

 white cottony wool. It is a native of the shores of 

 the Mediterranean and sandy shores in our eastern and 

 southern counties, but very rare in this country. The 

 hairs are no doubt a provision corresponding to the hot, 

 dry climate. 



Tanacettjm 



The flowers are all tubular, or if the outer ones are 

 ligulate, they are scarcely any longer than the others. 



T. vulgare (Tansy). — Flower-heads in a large corymb, 

 which is very conspicuous in spite of the small size of 

 the individual florets. It is evident that in a plant 

 so arranged ray flowers are unnecessary, and indeed, 

 except at the edge of the corymb, the rays would be 

 inconvenient. It is a nearly glabrous plant, found in 

 waste places, but probably not a true native. 



Artemisia 



Wind- or pollen-flowers. The florets are small, and 

 combined in small heads. The branches are easily 

 swayed by the wind. There are four British species. 

 Two have the leaf-segments narrow linear, while in the 

 other two they are broader. Of the former, A. maritima 

 has the stem and leaves cottony white, while in A. cam.- 

 pestris they are green or reddish. Of the two latter, A. 

 Absinthium (Absinth), has the leaves silky and whitish 

 on both sides, while in A. vulgaris they are green above. 



R 



