278 CICHORIACEAE 



Leaves oblanceolate, usiially entire, rarely with short broad lobes or 

 teeth. 

 All bracts linear-lanceolate and acute. 



Plant tall, slender, 3-5 dm. high; leaves erect; heads 2-3 cm. 



high. 22. .4. gracilens. 



Plant low, 1-3 dm. high; leaves spreading; heads 1.5-2 cm. 

 high. 23. ,4. Tiana. 



Outer bracts oblong or lanceolate, often obtuse. 



Plant low, 1 dm. liigh or less; inner bracts only sUghtly longer. 



24. A. carnca. 

 Plant taller, 3-5 dm. high; inner bracts much longer. 



25. A. aurantiaca. 

 Flowers light yellow, but often turning pinkish; inner bracts elongate in age. 



Involucres 2-2.5 cm. in diameter; plant tall and stout, scarcely glaucous. 



19. A. data. 

 Involucres less than 1 cm. in diameter; plant slender, glaucous. 

 Scapes tall, 2.5-4 dm. high, much e.xceeding the leaves. 



26. A. arizonica. 

 Scapes low, about 1 dm. high, sUghtly if at all exceeding the leaves. 



27. .4. Icplncarpa 

 Involucres of two distinct sets of bracts, the inner narrowly linear, 2-3 times as long 



as the ovate or oval outer ones ; beak 2-3 times as long as the body of the 

 achenes. 

 Leaves glabrous and glaucous, linear or oblanceolate, acuminate, with linear 

 lobes, or entire. 

 Outer bracts oblong-obtuse : lobes of the leaves linear to lanceolate, acute. 



28. A. rostrata. 

 Outer bracts acute or acuminate; lobes of the leaves narrowly linear. 



29. A. tenuifolia. 

 Leaves more or less pubescent, oblanceolate in outline. 



Leaves obtuse and with oblong-obtuse lobes. 30. A. obtusifolia. 



Leaves attenuate and with lanceolate, acute lobes. 31. A. grandiflora. 



III. Retrors.\e. 

 One species. 32. A. retrorsa. 



IV. Heterophyllae. 

 One species. 33. A. heterophylla. 



24. LEONTODON L. Dandelion. 



Outer bracts (calyculum") more or less squarrose. 



Outer bracts refle.xed from the base; leaves deeply runcinate, with triangular to lanceo- 

 late lobes. 

 Achenes bright red. 1. L. erylhrospermum. 



Achenes greenish or brownish. 



Bracts nimierous; leaves broad and the terminal lobe large. 



2. L. Taraxacum. 

 Bracts few; leaves narrow and the terminal lobe small. 3. L. mcxicanum. 

 Outer bracts or most of them appressed at the base and with spreading or reflexed 

 tips; leaves with short lobes or sinuate. 

 Bracts conspicuously corniculate, the outer about two-thirds as long as the inner; 

 scape usually much exceeding the erect leaves; achenes spinulose-toothed 

 above and tutaerculate on some of the ribs to near the base. 



4. L. dumclorum. 

 Bracts, at least the outer ones, not corniculate, the outer about half as long as the 

 inner; achenes merely tuberculate above, smooth below. 5. L. leiospermum. 

 Outer bracts wholly appressed, short, the mere tip rarely spreading. 



Plant not dwarf; scape 5-20 cm. liigh; involucres 15 mm. or more high. 



Plant with a tuft of browai hairs at the base. 0. L. eriophorum. 



Plant not with browai hairs at the base. 

 Achenes brow^ush or greenish. 



Calyculate bracts in 2-3 series; achenes miu'icate to near the base. 



7. L. monticola. 

 Calyculate bracts in 1-2 series; achenes smooth below the middle. 



8. L. angusii folium. 

 Achenes bright red. 9. L. ammophilum. 



Plant dwarf: scape 2-10 cm. high; involucres 6-12 mm. high, dark green. 



Involucres campanulate, 10-12 mm. high; lobes of the leaves oblong or lanceolate, 



acutlsh. 10. L. rupcslre. 



Involucres cyUndro-campanulate, 6-8 mm. high, 5 mm. broad; lobas of the leaves 



broadly triangular, obtuse. 11. L. scopulorum. 



5. LACTUCA (Tourn.) L. Lettuce. 



Achenes with a slender beak; pappus wliite. 



Outer bracts (cal.vculum) not more than half as long as the bracts proper; flowers 

 yellow, rarely tinged with blue. 

 Heads 6-lo-flowered; achenes several-nerved, not rugose; leaves spinulose on the 

 ribs. 

 Leaves sinuate-dentate; achenes dark. 1. L. virosa. 



Leaves sinuately pinnatifld; achenes Ught colored. 2. L. Scariola. 



Heads 12-20-flowered; achenes 1-3-nerved, transversely rugose. 

 Involucres about 1 cm. high. 



