COMPOSIT^E 639 



HELIANTHUS TUBEROSUS (Jerusalem Artichoke) 

 Description. — The Jerusalem artichoke is a perennial herb 

 arising from thick, fleshy rootstocks that bear oblong tubers 

 (Fig. 263). The above-ground stems attain a height of 6 to 12 

 feet; they are stout, branching, terete and hirsute. The leaves 

 are alternate above, opposite below, simple, ovate or ovate- 

 oblong, firm, three-nerved at the base, narrowed, rounded, 

 truncate or slightly heart-shaped at the base, acuminate at 

 the apex, and long petioled. The heads are solitary or in 

 corymbs. Tubular (disk) and hgulate (ray) flowers are both 

 present; the rays are yellow and the disk is also yellow (Fig. 

 254). The involucre is hemispheric, with lanceolate, acumi- 

 nate hirsute or ciliate, squarrose bracts. There are 12 to 20 

 rays. The receptacle is chaffy; the chaff subtends the disk 

 flowers. The achenes are thick, somewhat four-angled, and 

 pubescent. The pappus consists of two deciduous scales. 



Geographical. — The Jerusalem artichoke (also called Earth Apple, Canada 

 Potato, Girasole and Topinambour) is native to this country and is found 

 from New Brunswick and Ontario to Georgia and Arkansas, west and north 

 to Canada. It is grown as a crop more in Europe than in America. 



Closely Related Species.^ — The Jerusalem artichoke is 

 closely related to the "globe artichoke" {Cynara scolymus) 

 which in fact belongs to the same family, Compositae. 

 Cynara scolymus is sometimes cultivated for the flower heads 

 and leaves. The thick receptacle together with the fleshy 

 bases of the scales of the involucre is used as a vegetable. 

 The plant may be distinguished further from Jerusalem 

 artichoke by its blue or violet-purple flowers, and its large, 

 wooly, pinnatifid leaves. 



Uses. — The tubers of Jerusalem artichoke are used both 

 as a vegetable and as a food for stock. Hogs are turned into 

 the field and permitted to root the tubers from the ground. 



References 

 Tkacy, W. W.: American Varieties of Lettuce. U. S. Dept. Agr. Bur. Plant 

 Ind. Bull. 6q: 1-103, 1905. 



