102 SPRING FLORA 



21. ASTER. 



Mostly perennial, branching herbs. Leaves alternate. Heads 

 many-flowered; usually corymbose or panicled. Bracts of the 

 involucre firm; more or less imbricated. Ray-flowers pistillate; 

 white, blue or purple. Disk-flowers perfect; usually yellow, 

 changing" to red, brown or purple. Pappus mostly of simple, 

 capillary bristles. Achenes more or less flattened. 



1. A. ericaefolius Rothrock. (Leucelene ericqides (Tqrr.) 

 Greene). Stems several from deep roots; 3-12 inches high; 

 canescent and glandular-scabrous. Leaves hispid-ciliate; 

 spatulate; narrowing at base. Rays 12-15, white or drying to 

 red. Disk-flowers perfect, white. Pappus a single row of 

 slender white bristles. Dry plains and hillsides. May-August. 



22. ERIGERON. Flea-bane. 



Herbs with entire or toothed, usually sessile leaves. Heads 

 solitary or corj^mbose. Involucral bracts narrow, equal, im- 

 bricated, usually in 1 row; seldom leathery or green-tipped. 

 Ray-flowers narrow; white, violet or purple; usually very 

 many; pistillate. Disk-flowers yellow, not fading to purple. 

 Pappus scanty, of dull-white bristles. A genus much resem- 

 bling Aster, from which it is distinguished by the involucral 

 bracts and the constant color of the disk-flowers. 



Ray-flowers inconspicuous 1. E. minor 



Ray-flowers conspicuous. 



Perennials; heads large, rays white. 



Pappus double. 2. E. uumilus 



Pappus single 3. E. Engelmannii 



Annual or biennial; heads many, small; rays colored. 



Rays about 100; pappus double 4. E. diver-gens 



Rays 30-65; pappus single 5. E. Bellidiastrum 



1. E. minor (Hook.) Rydb. Stems weak, hairy, branched, 

 5-12 inches high; often several from the same root. Leaves 

 entire, those of the stem sessile. Bracts or involucre narrow, 

 abruptly acute, never glandular. Rays white. Wet meadows. 

 June-August. 



2. E. [Himilu.s Nutt. "Wild Daisy." Perennial from a tap- 

 root; a foot or less high, conspicuously hispid or hirsute with 

 spreading bristly hairs. Leaves petioled or upper stem leaves 

 sessile; from linear-spatulate to lanceolate (the upper linear), 

 entire. Involucre hispid. Rays 50-80. Achenes pubescent. Dry 

 gravelly plains. May-July. 



3. E. Engelmannii A. Nels. Stem slender, ascending, weak, 

 several from the same root. Leaves many, linear, slender- 

 petioled, 1-nerved. Heads 1-3 on each stem smaller than those 

 of No. 2. Bracts ciliolate. Rays about 40. Hillsides. May- 

 June. 



4. E. divergens T. & G. Stems several from a stout tap-root, 

 6-15 inches high, diffusely branched above; densely ashy- 

 pubescent or hirsute. Heads numerous, slender-pedicelled, y 2 -l 

 inch broad. Raj's narrow, about 100; purplish or violet. Pap- 

 pus double. 



5. E. Bellidiastmm Nutt. A much-branched grayish-pubes- 

 cent annual, about a foot high. Leaves spatulate. Heads small, 

 numerous, with lilac or light-bluish rays. Dry sandy plains. 

 May-June. 



