~~ 
462 CocCKERELL: NortTH AMERICAN SPECIES OF HYMENOXYS 
sent a series of especially interesting and important plants from 
his collection. To all of these my thanks are due. 
Hymenoxys is separated from <Actinella (which includes our 
Picradenia) in the Genera Plantarum of Bentham & Hooker, but 
anyone who will compare the description will see that no substan- 
tial difference is indicated. Gray in the Synoptical Flora, treats 
Hymenoxys as a synonym of Actinella, referable to the section of 
that genus which includes Picradenia. Greene and others, seeing 
that typical Hymenoxys was a rayless plant of South America, felt 
satisfied that Picradenia was distinct, and I had adopted this view 
without serious misgivings. At Kew Herbarium, however, I have 
been able to examine species of HYymenoxys, and much to my 
regret (on account of the nomenclatural changes it compels) I am 
quite unable to separate the South American genus from Picradenia. 
In the herbarium, indeed, Actinel/la chrysanthemoides is placed in 
the Hymenoxys-cover, though it is absolutely congeneric with our 
plants of Texas, etc. There is nothing in the structure or habit 
to separate f/ymenoxys from Picradenia, and the absence of rays 
cannot be considered important, as they may or may not be pres- 
ent in Gailardia, and moreover Hymenoxys Tweediei Hook & Arn., 
from Uruguay, has very well-developed rays. This H. 7 qwecaiel, 
in its foliage and manner of growth, closely imitates our /7, (oF 
Picradenia) Lemmoni. Hymenoxys Haenkeana DC. has heads not 
unlike those of the Mexican H. chrysanthemoides. Hymenoxys 
anthemoides Cass., which is typical of the genus, looks just like our 
annual plants of the forms intermediate between chrysanthemoides 
and multiflora. The material examined has dark red pappus-scales 
and hairs on the achenes just as in some of our Picradenia forms. 
The separation of Zetraneuris, Rydbergia and Macdougalia* 
from Hymenoxys appears to be justified. Actinella Palmeri Gray, 
1883, forms still another genus ; taking up the subgeneric name pro- 
posed by Gray, it becomes Plateilema Palmeri. It is not only very 
distinct in its foliage and manner of growth, but its angular achenes, 
with ciliate margins, are very distinctive, not to mention the peculiar 
* Macdougalia has only one known species, JZ. Bigelovii (Gray) Heller. This is 
cited in the Synoptical Flora only from New Mexico, but I have examined material (hb. 
U. S. Nat. Mus.) from San Francisco Mountain (Jones), near Flagstaff, 5500 ft. (Mac- 
Dougal), Willow Spring (Pa/mer) and Williams ( Rusby,) all in Arizona. 
