FLOWERIXG PLANTS AXD FERNS OF ARIZONA 923 



28. EPJGEROX. Fleabane, wild-daisy 



Herbs; leaves alternate, sometimes all basal, usually narrow, entire 

 to pinnatifid; heads small or medium-sized, radiate or rarely discoid, 

 the rays white, pink, or purple, the disk yellow; involucre usually only 

 slightly or not at all graduated, the phyllaries not herbaceous-tipped, 

 but sometimes subherbaceous throughout; achenes usually 2-nerved, 

 sometimes 4- to 10-nerved; pappus usually sparse, of subequal capillary 

 bristles, sometimes with an outer series of short squamellae or bristles; 

 appendages of the style short, triangular, obtuse or rounded. 



Many of the species have attractive daisylike heads, with blue, 

 lavender, or white rays. An oil distilled from horseweed, E. canaden- 

 sis, was formerly prescribed for diarrhea and dysentery. This 

 plant is reported to cause irritation of the. throat and dermatitis in 

 susceptible persons. When eaten by livestock, it may cause colic, 

 but in Arizona the species is not sufficiently abundant to be a serious 

 pest. 



Key to the species 



1. Rays very short and inconspicuous, not or only slightly exceeding the pappus 



rarely wanting 2 . 



2. Plants perennial, dwarf, rarely more than 15 cm. high, often scapose, the 



scapes or stems 1- or few-headed (3). 



3. Lower leaves spatulate, ciliate, essentially glabrous on the faces; plant 



loosely pilose 1. E. simplex. 



3. Lower leaves narrowly linear-spatulate, hispid like the whole plant. 



9. E. CONCINNUS. 

 2. Plants annual, normally 30 cm. high or more, leafy-stemmed, several- or 

 many-headed (4). 



4. Plant gray-tomentose, without stiff or glandular hairs; stem sparsely 



branched above, the branches nearly naked; lower leaves oblanceolate, 



toothed 27. E. eriophyllus. 



4. Plant green, with stiff or glandular hairs or both (5). 



5. Plant loosely arachnoid-pilose, also glandular, especially on the leaves 

 and heads; leaves lanceolate or oblong-lanceolate, sessile and some- 

 what clasping, few-toothed; heads medium-sized, about 6 mm. high, 

 numerous, in a narrow leafy racemiform or spikelike panicle. 



28. E. SCHTEDEANUS. 



5. Plant hispid, hirsute, or strigose, not glandular; leaves not clasping; 

 heads otherwise (6). 

 6 Heads relatively large (6 to 8 mm. thick); involucre densely hirsutu- 

 lous; plant relatively low (usually 40 cm. high or less), grayish 



green, densely hispid and hispidulous 29. E. lixifolius. 



6. Heads tiny (about 2 to 4 mm. thick, about 4 mm. high), usually very 

 numerous, in an elongate panicle; involucre essentially glabrous 

 or sparsely hispidulous: plant usually tall (1 m. or more), green, 

 rather sparsely hispid to essentially glabrous (7). 

 7. Phyllaries not with colored tips; plant usually hispid. 



30. E. CANADENSIS. 



7. Phyllaries with definite purplish tips; plant glabrous or practically 



so 31. E. PUSILLUS. 



1. Rays present and conspicuous, much exceeding the pappus (8). 



8. Stem leaves all deeply pinnatifid, with several pairs of linear lobe*; plants 

 perennial, normallv 30 to 50 cm. high, leafv throughout: ravs white or 

 pinkish (9). 

 9. Stem hispid or hirsute but not glandular-puberulous. 



2"). E. NEOMEXICANTTS. 



0. Stem glandular-puberulou* as well as hispid or hirsute._26. E. oreophilus. 

 8. Stem leaves entire or, if rarely pinnatifid, then the plant either low, or not 

 leafy throughout, or annual or biennial (10). 



