250 SYSTEMATIC BOTANY. 



C. INTYBUS (Succory). Stem terete, with several long, nearly simple 

 branches ; upper ones oblong or lanceolate, more or less clasping at base, 

 slightly dentate or entire, small and inconspicuous ; heads 2-3 together, axil- 

 lary, sessile, light blue, showy ; corolla 5-toothed. July-September. 



25. Leontodon. Heads many-flowered. Involucre scarcely im- 

 bricated, with several small scales at base. Receptacle naked. Pap- 

 pus plumose, persistent. Achenia striate, somewhat rostrate, if 



L. AUTUMNALIS (Autumn Dandelion}. Acaulescent ; scape smooth, 

 branching ; leaves radical, lanceolate, pinnatifid ; peduncles scaly, thickened 

 upward ; heads yellow, on separate peduncles, resembling somewhat those 

 of the dandelion. July-November. 



26. Lactuca. Heads several-flowered. Involucre-scales in 2 or 

 more rows. Pappus copious, fugacious, soft and capillary. Achenia 

 compressed, with long, filiform beaks. 



1. L. ELONGATA ( Wild Lettuce). Stem tall, stout, usually leafy, branch- 

 ing above ; leaves smooth, paler beneath, entire, sessile ; heads small, nu- 

 merous, racemose on the branches, forming a long, naked panicle ; corolla yel- 

 low, rarely purple ; achenia oval. Plant, abounding in a milky juice, 2-6 

 feet high. In rich, moist soils. 



2. L. SATIVA (Garden Lettuce}. Stem smooth, branching, corymbose 

 above ; leaves more or less orbicular, very smooth ; cauline ones cordate ; 

 heads numerous, small, yellow, in terminal corymbs. Universally cultivated. 

 June-July. 



27. Hieracium. Heads many-flowered. Involucre-scales usually 

 more or less imbricate. Achenia striate, oblong, more or less rostrate. 

 Pappus of tawny, fragile, capillary bristles, in a single row. y. 



1. H. CANADENSE (Canadian Hawkweed}. Stem leafy, somewhat pubes- 

 cent ; leaves lanceolate, or oblong-ovate, acute, dentate with coarse and acute 

 teeth, sessile ; heads large, on hairy peduncles, forming a terminal, panicu- 

 late corymb ; involucre-scales linear, imbricated. In dry woods, 1-2 feet high. 

 August. 



2. H. VENOSUM ( Veiny Haiukweed}. Mostly acaulescent ; stem or scape 

 slender, smooth, often with i or 2 leaves, branching, loosely corymbose 

 above ; radical leaves obovate, sometimes oblong, nearly entire, on very short 

 petioles, hairy above, ciliate, marked with purplish veins ; heads rather small, 

 solitary, bright yellow. In dry woods, 1-2 feet high. July-August. 



3. H. SCABRUM (Rough Hawkweed*). Stem leafy, nearly simple, rough, 

 hairy ; leaves hairy, nearly entire ; lower ones obovate, slightly petiolate, 

 upper ones oval, sessile ; peduncle thick, glandular-hispid ; heads 4c-5o-flow- 

 ered. In dry soils, 15^24' high. 



28. Nabalus. Involucre cylindrical, with 5-10 linear scales in one 

 row, and a few scales at base. Receptacle naked. Pappus-bristles 

 copious, capillary, brownish or straw-color, in two series. Achenia 

 striate, linear-oblong, without beaks. % 



