128 PLANTS OF YELLOWSTONE NATIONAL PARK 
Antennaria aprica and A. Janata have also been reported as occur¬ 
ring in the park. 
Pearl everlasting ( Anaphalis margaritacea) .—A white-woolly, per¬ 
ennial herb with small heads of yellow disk flowers but no ray flowers. 
It commonly grows 10 to 20 inches high with the stems in clusters 
and is very leafy. The leaves are lance-shaped and 2 to 4 inches 
long and the broader ones are indistinctly three-nerved. The heads 
are numerous and the involucres are pearly white. 
Cudweed ( Gnaphalium wrightii) .—This is a very woolly plant that 
is quite common on the hot springs formations. The stems are 4 to 
8 inches high and usually consid¬ 
erably branched. The leaves are 
sessile, the basal ones oblanceolate 
and more than an inch long, while 
those on the stem are smaller and 
vary to linear. The heads are 
sessile in small, close clusters at the 
ends of the branches. The bracts 
are dull white. 
Gnaphalium chilense has been 
reported in the park. 
Sumpweed {Iva axillaris).—A 
low, rather coarse herb with stems 
4 to 6 inches high and thickish, en¬ 
tire, sessile leaves, which are oblong 
or nearly linear and a quarter of 
an inch or more long. The small 
heads of greenish-white flowers are 
borne singly in the axils of the 
upper leaves. There are no ray flow¬ 
ers and no pappus, but there are chafflike bracts between the disk 
flowers. The bracts of the involucre are few in number and they are 
grown together in such a way as to form a 4- or 5dobed cup. 
Mggerthumb (Rudbeclcia occidentals) .—A nearly smooth, stout 
plant with stems 2 to 7 feet high and nearly unbranched, except 
at the top. The alternate leaves are ovate to lance-shaped, rather 
long-pointed, entire or nearly so, and 4 to 8 inches long. The 
upper ones are sessile with rounded or heart-shaped bases, while the 
lower ones have short, winged petioles. The heads are few in number 
but large and many-flowered. There are no ray flowers and the disk 
flowers are brownish and have brown, chaffy scales between them. 
The heads are 1 or 2 inches long. Found mostly in moist, shady 
places. 
Figure 104.—Pearl everlasting. White. 
Photograph by Joseph S. Dixon, Na¬ 
tional Park Service. 
