Hardy Exotic Flowering Plants 155 



it would not suffer much from storms. The old Dragon 

 plant (A. Dracontium) grows freely enough about the foot 

 of rocks or walls in sandy or dry peaty places. The nearly- 

 allied Arum Lily (Calla sethiopica) is quite hardy as a water 

 and water-side plant in the southern counties of England 

 and Ireland. 



Silk'weed, Asclepias. — Usually vigorous perennials, with 

 ■ very curious flowers, common in fields and on river banks in 

 North America and Canada, where they sometimes become 

 troublesome weeds. Of the species in cultivation, A. Cornuti 

 and A. Douglasi could be naturalized easily in rich deep 

 soil. The showy and dwarfer Asclepias tuberosa requires 

 very warm sandy soils to flower as well as in its own dry 

 hills. A good many of the hardy species are not introduced ; 

 some of them are water-side plants, such as A. incarnata, the 

 Swamp Silkweed of the United States. 



Starwort, Aster. — A very large family of vigorous, often 

 beautiful perennials, mostly with bluish or white flowers, 

 chiefly natives of North America. Many of these, of an 

 inferior order of beauty, used to be planted in our mixed 

 borders, which they very much helped to bring into discredit, 

 and they form a very good example of a class of plants for 

 which the true place is the copse, or rough and half-cared-for 

 places in shrubberies and copses, and by wood-walks, where 

 they will grow as freely as any native weeds, and in many 

 cases prove charming in autumn. With the Asters may be 

 grouped the Galatellas, the Vernonias, and also the handsome 

 Erigeron speciosus, which, however, not being so tall, could 

 not fight its way among such coarse vegetation as that 

 in which the Asters may be grown. Associated with 

 the Golden Rods (Solidago)— also common plants of the 

 American woods— the best of the Asters or Michaelmas 



