Hardy Exotic Plants for Naturalization. 91 



plant. The fine variegated kinds thrive perfectly in 

 woods and semi-wild spots, in any kind of soil. 



Lesser Periwinkle. Vinca minor. Europe. Trailer ; 

 I foot; blue; summer; division. — Similar positions to 

 preceding. There are many varieties, all good, 



THE SWALLOWWORT FAMILY. 



Douglas's Swallowwort. Asdepias Douglasii. North 

 America. Herbaceous perennial ; 4 feet ; purple ; sum- 

 mer ; seed or division. — -Among the finer herbaceous 

 plants in copses, on margins of shrubberies, or on 

 banks, in rich and deep soil. 



Cornuti's Swallowwort. Asdepias Cornuti. North 

 America. Herbaceous perennial ; 5 feet ; purple ; sum- 

 mer ; seed or division. — Similar positions to preceding ; 

 but this plant is suited for association with the tallest and 

 most vigorous herbaceous subjects. 



THE GENTIAN FAMILY. 



Stemless Grentian. Gentiana acaulis. Central 

 Europe. Evergreen perennial ; 2 to 4 inches ; blue ; 

 early summer; division. — Bare rocky places; seldom 

 thrives in dry soil. Would grow on bare ground on our 

 mountains or high hills as well as it does on the Alps. 



Swallowwort Gentian. Gentiana asdepiadea. 

 Austria. Herbaceous perennial ; i to 2 feet ; blue ; 

 summer; seed or division. — ^Amidst the finer dwarf 

 herbaceous plants, on the margins of woods and copses, 

 on rough rockwork, &c., in ordinary soil ; best, however, 

 in peat or very light sandy loam. 



