934 ERYTHEA. 
psoralifolia O. and C. diffusa with but short stipes, and C. 
aculeata with this organ nearly obsolete.—F. von MUELLER, 
Melbourne, Australia, Aug. 21st, 1893. 
[The above commentary relates to my article on page 114 
of this volume, in which I suppress Robert Brown’s Jack- 
sonia after having restored that of Rafinesque; and Baron 
von Mueller’s comments show that he wholly misapprehends 
the characters on which Rafinesque’s JACKSONIA is based, 
though we have twice announced them very distinctly in Pit- 
tonia (Vol. ii, pp. 174 and 274). Neither the number of the 
stamens nor the presence or absence of a stipe need be con- 
sidered in discussing the merits of this genus as distinct from 
Cleome. Itis, I believe, also true that our J acksonia (after- 
wards renamed Polanisia by Rafinesque himself), is exclus- 
ively North American. It was De Candolle who extended _ 
the limits of Polanisia to include Old World plants which, 
whatever else they have, do not possess the real characters 
of the genus. We are at full agreement with Baron von 
Mueller as to the insufficiency of the absence of stipe and 
the multiplied stamens; but if he will examine typical species 
of Jacksonia, Raf. and the only species known to that 
author, he will find it a thoroughly acceptable genus; and 
also that the validity of the name JacKsonta, as the prior 
one, cannot be gainsaid.—E. L. G.] 
Carduus heterolepis. 
In looking over your Philadelphia Academy paper on the 
Thistles, I note that you describe a Carduus heterolepis, and 
state that you cannot find any published description of it 
under Cnicus. It appeared in the tenth volume of the Pro- 
ceedings of the American Academy (p. 44), in a foot note by 
Dr. Gray. It is also the Cnicus subcoriaceus of Hemsley.— 
J. N. Rosz, Washington, D. C., 14 July, 1893. 
