84 



NORTH AMERICAN FLORA 



[Volume 34 



Annuals. 



Bracts in 2 series, ovate. 

 Bracts in 1 series, oblong. 



Heads narrow, short-peduncled ; rays inconspicuous. 

 Heads eampanulate, long-peduncled, conspicuously radiate. 

 Rays 2-3 mm. long; bracts usually united. 



Bracts acute; leaves spatulate, toothed or lobed. 

 Bracts acuminate; leaves narrowly oblanceolate. 

 Rays 5-8 mm. long; leaves mostly entire; bracts usually distinct. 

 Involucre 6—7 mm. high; pappus-squamellae minute or 



wanting; leaves sparingly floccose. 

 Involucre 7-8 mm. high; pappus-squamellae 1.5-2 mm. 

 long ; leaves densely tomentose. 

 •Perennials (sometimes blooming the first year). 



Heads comparatively large on long peduncles, mostly solitary. 



■Leaves not deeply dissected, entire, toothed, or shallowly lobed. 

 Leaves entire or with few teeth or lobes at the apex, thick and 

 equally tomentose on both sides, except in E. pednnculatum 

 and E. Harfordii. 

 Achenes glabrous or nearly so. 



Leaves obovate or broadly oblanceolate; pappus-squam- 

 ellae 1-2 mm. long. 

 Leaves coarsely 3-5 -toothed at the apex; squamellae 

 broadly oblanceolate, about 2 mm. long. 

 Plant with rather sparse yellowish tomentum. 

 Plant very densely white-tomentose. 



Plant 1 dm. high or less; involucre about 7 mm. 

 high, 8-10 mm. broad; ligules 7-8 mm. long. 

 Plant 1.5-2 dm. high; involucre 8-10 mm. 

 high, 10-15 mm. broad; ligules 8-12 mm. 

 long. 

 Leaves entire or minutely several-toothed ; squamellae 

 narrowly lanceolate or linear-oblong, about 1 mm. 

 long. 

 Leaves narrowly linear-oblanceolate. 



Pappus-squamellae minute, scarcely 0.3 mm. long; 



leaves 1-2 cm. long. 

 Pappus-squamellae 1-2 mm. long; leaves 3-5 cm. 

 long. 

 Achenes decidedly pubescent or glandular, or both. 



Leaves entire, only the basal ones toothed at the apex. 

 Leaves narrowly linear-oblanceolate. 

 Leaves oblanceolate to obovate. 

 Leaves nearly all toothed or even lobed. 



Heads 10 mm. broad or less; stems low, decumbent 



at the base. 

 Heads 12-15 mm. broad; stems tall, erect. 

 Leaves serrate with comparatively small teeth, rarely at all 

 lobed. 

 Plant densely white or yellowish villous-tomentose. 

 Plant less tomentose; leaves loosely floccose and greenish 

 above. 

 Achenes glabrous; pappus minute; leaves very thin. 

 Achenes hirsute; pappus fully 1 mm. long; leaves some- 

 what thicker. 

 Leaves more deeply dissected, the sinuses extending at least half- 

 way to the midrib. 

 Blades mostly cuneate, rhombic, or rhombic-oblanceolate in 

 outline, 3- (or rarely 5-) cleft into rather broad and entire 

 (or nearby so) divisions. 

 Leaves thin, floccose and glabrate above. 

 Achenes glandular-muricate. 



Leaves rhombic-oblanceolate in outline; lobes lanceo- 

 late, acute. 

 Leaves rhombic-obovate in outline; lobes oblong 

 or elliptic, obtuse. 

 Achenes glabrous; leaves rhombic-cuneate in outline. 

 Plant low, rarely 4 dm. high; annual branches 



monocephalous; lobes of the leaves entire. 

 Plant tall; annual stems corymbosely branched 

 above; leaf -lobes usually more or less sinuate- 

 dentate. 

 Leaves thick, densely white-tomentose on both sides. 

 Achenes glabrous. 

 Achenes pubescent or glandular. 

 Blades of the stem-leaves ovate-lanceolate in outline, their 

 divisions either linear, narrowly lanceolate, or oblong, 

 or else again divided. 

 Achenes hairy. 



1. E. minus. 



2. E. nubigeniim. 



3. E. parviflorum. 



4. E. ambiguum. 



5. E. paleaceum. 



6. E. Congdoni. 



19. E. Harfordii. 

 26. E. Bolanderi. 



20. E. cunealum. 



21. E. caespiiosum. 



9. E. leiicophyllum. 



15. E. Irichocarpum. 



