1034 CICHORIACEAE 



campanulate, 12-18 mm. high; bracts in 3 series, the outermost bracts ovate- 

 lanceolate, the innermost linear-lanceolate, all acute; flowers light yellow; mar- 

 ginal achenes with broad wavy wings or wingless, the central ones merely costate; 

 body about 5 mm. long; beak filiform, about 1 cm. long. Macrorhynchus hetero- 

 phyllus Nutt. Hills and prairies: Calif. Utah Ida. B.C. Son. My-Je. 



24. LEONTODON L. DANDELION. 



Acaulescent perennial herbs, with pinnatifid fleshy taproots, toothed or 

 rarely entire leaves, and the heads solitary on naked hollow scapes. Involucre 

 campanulate; bracts equal, subtended by a well-developed calyculum of shorter 

 bracts, the calyculate bracts in several series. Receptacle naked. Flowers 

 yellow. Achenes mostly fusiform, 4- or 5-angled, 8-10-ribbed, retrorsely spinu- 

 lose above, contracted into a slender beak. Pappus of numerous persistent 

 bristles spreading in fruit. [Taraxacum (Haller) Ludv.] 



Outer bracts (calyculum) more or less squarrose. 



Outer bracts reflexed from the base; leaves deeply runcinate, with triangular to lanceo- 

 late lobes. 



Achenes bright red. 1. L. erythrospermum. 



Achenes greenish or brownish. 



Bracts numerous; leaves broad and the terminal lobe large. 



2. L. Taraxacum. 



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

 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 tuberculate on some of the ribs to near the base. 



4. L. dumetorum. 

 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. high; involucres 15 mm. or more high. 



Plant with a tuft of brown hairs at the base. 6. L. eriophorum. 



Plant not with brown hairs at the base. 

 Achenes brownish or greenish. 



Oalyculate bracts in 2-3 series; achenes muricate to near the base. 



7. L. monticola. 

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



8. L. angustifolium. 

 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, 



acutish. 10. L. rupestre. 



Involucres cylindro-campanulate, 6-8 mm. high, 5 mm. broad ; lobes of the leaves 



broadly triangular, obtuse. 11. L. scopulorum. 



1. L. erythospermum (Andrz.) Eichw. Leaves 1-2 dm. long, oblanceolate 

 m outline, deeply runcinate-pinnatifid to near the midrib; lobes with a triangular 

 base, more or less caudate-lanceolate; scape 1-3 dm. high; involucres about 15 

 mm. high; inner bracts 12-20, linear, with a lanceolate, slightly scarious-margined 

 base; achenes 3 mm. long, bright red; ridges spinulose above and muricate 

 below to the very base. Taraxacum erythrospermum Andrz. Roadsides and 

 around dwellings: Me. W. Va. Kans. Wyo. Alta. ; nat. from Eu. My-Au. 



2. L. Taraxacum L. Leaves 1-3 dm. long, oblanceolate in outline, usually 

 deeply runcinate, with triangular, more or less cut-toothed lobes, the terminal 

 division large, deltoid or deltoid-ovate; scape 1-3 dm. high; involucres about 15 

 mm. high; inner bracts linear-lanceolate, 15-25, with narrow scarious margins, 

 rarely corniculate; achenes greenish or brownish yellow, the ridges spinulose 

 above, then muricate and nearly smooth at the base. T. officinale Weber. T. 

 laraxacum Karst. Around dwellings, fields, and roadsides: Lab. S.C. Calif . 

 Alaska; nat. from Eu. PlainMont. Mr-N. 



3. L. mexicanum (DC.) Rydb. Leaves 1-1.5 dm. long, narrowly oblanceo- 

 late, deeply runcinate, with retrorsely obliquely triangular, often toothed lobes; 

 terminal division small, deltoid; scape 5-15 cm. long; involucres about 15 mm. 

 nign, green or slightly livid; inner bracts narrowly linear, lanceolate, scarious- 



argined t9wards the base, 12-20 in number; achenes about 3 mm. long; ridges 

 rongly spinulose above and muricate usually to the very base. T. mexicanum 



