Hog and Jerusalem Artichokes. 31 



words " distinct variety;^ instead of " distinct species of He- 

 li an thus." I hope, too, that I have wounded the feelings of 

 no one by an imphed distrust in the ability of other botanists, 

 to settle this little matter, by naming Drs. Torrey and Gray, 

 as those with whose determination I should rest quietly satis- 

 fied ; for it is well known that the characters of the species in 

 most of the order Compositse, especially in the large genera, 

 are often obscure and puzzling, — requiring great practical skill 

 and access to the most recent published descriptions and col- 

 lections of dried specimens, to enable one satisfactorily to set- 

 tle the name of a kind which he has never seen before. 



My opinion, when given, was based principally on the dif- 

 ference in the form of the tubers ; — and it is, I believe, a re- 

 ceived canon in Botanical nomenclature, that a difference in 

 the structure of any of those parts from which the specific 

 characters are taken, — provided it be constant, and propaga- 

 ted by seed, shall be regarded as a sufficient ground for be- 

 stowing a different specific name. It is true that 1 have not 

 applied the test of raising them from the seed, but I have, for 

 several seasons, grown the two kinds, side by side, in my 

 garden, and note the following distinctions : — 



The tubers of the Jerusalem artichoke, {fig. 2) are commonly 

 produced in a compact clump around the foot of the stalk, sel- 



Fig. 2. Outline of a tuber of the Jerusalem Artichoke of the natural size. 



dom spreading over an area of more than 12 or 18 inches in 

 diameter, but often lying touching one another like eggs in a 

 basket. Their general form approaches the globular, and in 



