674 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
33. ERIGERON L. FLEeABANE. 
Annual or perennial herbs, sometimes woody at the base, with entire or toothed, 
mostly sessile leaves, these sometimes all basal; heads solitary or corymbose, often 
showy, the disk flowers yellow, the rays white to purple, sometimes short and incon- 
spicuous, rarely wanting; involucral bracts narrow, imbricated in 2 to 4 series, the 
outer sometimes shorter; receptacle flat or convex, naked; achenes flattened or nearly 
terete, pubescent or glabrous, smooth or striate; pappus a single series of bristles or 
with an outer series of short bristles or inconspicuous palee. 
KEY TO THE SPECIES. 
Bracts of the involucre in 8 or 4 series, imbricated, thickened 
on the back, the outer successively shorter. 
Pubescence spreading; basal leaves oblanceolate, obtuse.... 1. FE. caespitosus. 
Pubescence appressed; basal leaves linear or linear-oblanceo- 
late, mostly acute. 
Achenes glabrous. ..............-.22-----2--5--------0-- 2. BE. canus. 
Achenes pubescent. 
Heads large, 10 to 12 mm. broad; stems sparingly strigose; 
bracts thin. ......-.....2--2...00..00--2-2--.------ 3. EL pulcherrimus., 
Heads small, 6 to 8 mm. broad; stems densely grayish- 
strigose; bracts very thick....................-..--- 4, E, utahensis. 
Bracts in 1 or 2 series, about equal, not thickened on the back. 
Rays inconspicuous, slightly if at all exceeding the disk, 
usually with a row of rayless pistillate flowers inside; 
heads racemose...........2--.2- 22-2200 2 00200. e eee eee 5. EB. minor. 
Rays conspicuous (in one species wanting), much longer than 
the disk, without rayless pistillate flowers inside; heads 
not racemose. 
Plants with runners, at least at maturity. 
Leaves and stem with spreading pubescence............ 6. FE. commixtus. 
Pubescence all appressed. 
Whole plant nearly glabrous, bright green; heads about 
5mm. broad.............-...-2-..2..---2-2.-------- 7. E. tonsus. 
Plants abundantly strigose, grayish; heads more than 
5 mm. broad. 
Stems branched at the base; cauline leaves narrowly 
oblanceolate to linear, acute.................. 8. E. flagellaris. 
Stems branched above the base; cauline leaves obo- 
vate or oblanceolate, obtuse...............0..-. 9. EH. senilis. 
Plants without runners. 
Annuals or biennials., 
Cauline leaves broad, cordate-clasping; rays white or 
pink... 22.06... eee cece cece cee eee 10, EF. philadelphicus. 
Cauline leaves narrower, not cordate-clasping; rays 
variously colored. 
Pubescence more or less appressed, not always 
closely. 
Rays about 100; disk 7 to 8 mm. broad.......... LL.E. gilensis. 
Rays 40 to 50 or fewer; disk less than 7 mm. broad, 
Pappus in 2 series; rays narrow; achenes slightly 
compressed .........---20..2.220222 0 ee eee 12. E. modestus. 
Pappus in a single series; rays broader; achenes 
conspicuously compressed, 
