CocKERELL: NorTH AMERICAN SPECIES OF HymENoxys 463 
bracts. On the other hand, the fibrillose receptacle is not an absolute 
character to separate Gaillardia from Hymenoxys. As amatter of fact 
the broad-receptacled species of Hymenoxys do have the lowermost 
of the achene-hairs attached to the rim of the achene socket, and if 
the achenes are carefully removed the receptacle seems more or 
less fibrillose. Moreover there are admitted into the genus /Vaveria 
two species (F/. australasica and F. repanda) in which the recepta- 
cle is setose, while in the rest of the species it is bare. On other 
characters, I think Gai//ardia is quite sufficiently distinct from 
Hymenoxys, but it is difficult to express the peculiarities in a rigid 
mechanical way. Phileozera is no doubt a valid subgenus; with 
the help of a little imagination, one could almost believe it to have 
originated independently from some Anthemoid ancestor. I do 
not suppose, however, that anything of this sort has really taken 
place; it is possible for Anthemoid characters to arise among the 
Helenioids, even so as to deceive the very elect. Most assuredly 
Leucampyx Newberryi Gray, placed by its author as the first genus 
of Anthemideae, is nothing but a rayed Hymenopappus ; related, 
of course, to H/. radiatus Rose. If we are to keep up the genus 
Leucampyx, certainly H. radiatus must be included. I have 
studied both it and Z. Newderryi in the living state, and they look 
as much alike as they could without being quite the same. 
The more essential characters of Hymenoxys are found in the 
hairy and usually slender achenes ; the pappus-scales ; the bracts 
of the involucre in two series, the outer united basally ; the strongly 
punctate foliage, usually linear or divided into linear divisions. 
The genus is remarkably conservative in regard to these things, 
and yet in many other respects extremely plastic. The combina- 
tion of great racial variability with a marked ability to become 
directly modified by existing conditions makes it unusually hard 
accurately to define the species and subspecies. 
+ 
SUMMARY OF THE CLASSIFICATION 
Subgenus Picradenia (Hook. 1833) 
Plants with the aspect of Gatllardia or Helenium, t ] t ; foliage 
linear or divided into linear segm te ; inner bracts almost always con- 
spicuously different from the outer, Spe fimbriate ; disc-corollas not expanded a; 
the mouth ; rays well-developed. Perennials or biennials, never annuals. Type, 
A, Rix hindeu i : : 
