STUDIES IN THE COMPOSITA. 49 
which, up to the time of its discovery, had ever been dis- 
posed underthe genus Aster. In habit, and also in its essen- 
tial characters, if you make little or no account of the color 
of flowers, the species is indeed much more like Prionopsis, 
to which this author at the first referred it, than like Aster, 
" where he at length concluded to place it. 
There is, however, another yellow-flowered genus to which, 
according to my criteria of affinities, this plant and its allies 
are more nearly related than to either Aster or Prionopsis, 
and that is Pyrrocoma. But the Pyrrocoma species are yel- 
low-flowered and have fusiform roots, while the plants here 
under consideration have tuberiform roots or rootstocks, and 
rays either white or purplish ; and what is more, their dis- 
tinetly paleaceous-dilated and flattened pappus-bristles are 
those of a genus distinct from either. 
These interesting plants of our southern seaboard cannot, 
I think, be reasonably transferred to Pyrrocoma or left in 
Aster. They seem simply to demand the recognition of 
De Candolle's HetzastruM; though this was founded on 
that one of the three or four species whose pappus-bristles 
are least dilated, and which in habit is least unlike Aster, 
and which is therefore least worthy of being taken for the 
type of a genus. 
The vegetative characters of the genus, and natural group- 
ing of species, are well given in Gray’s Synoptical Flora, 
p. 173, though only as a subgenus of Aster. I infer from 
what is said by Aiton and by Elliott, both of whom knew 
the living plants, that the disk-flowers, at least in H. paludo- 
sum, and probably in all, are permanently yellow, 4. e., not 
changing to red or purple. "This, if it be true, will stand as 
an additional eharacter for the genus, the species of which I 
here enumerate. 
1. H. CHAPMaNir.  Prionopsis? Chapmanii, Torr. & Gray, 
Fl.ii.245 (1842). Aster eryngitfolius, Torr. & Gray, l. e. 502 
(1843).— Plant of low pine barrens along the coast of Florida. 
7 ! candi 
