COMPOSITACEAE (COMPOSITE FAMILY) 225 



n. Most of the leaves on the stem; ray flowers neutral; pappus of 2-6 deciduous 

 scales or awns. HELIANTHUS (p. 227) 



HH. Heads less than 2.5 cm. wide; involucre bracts boat-shaped, more or less 

 inclosing an outer or ray akene; leaves lanceolate or narrower (except Lago- 

 phylla). 

 K. Akenes flattened at right angles to the involucre; involucre bracts keeled 

 on back; plants mostly viscid-glandular; pappus none except in M. madioides, 

 of 5-8 scales. — (From madi, the name in Chile.) Madia (tarweed) 



KK. Akenes not flattened at right angles to the involucre; involucre bracts 

 rounded or flattish on the back. 

 L. Pappus none. 

 M. Leaves of the stem pinnatifid; leaves of the branches and fascicles entire, 

 spinulose-tipped; involucre bracts spinulose-tipped; disk flowers lo or more; 

 ray flowers lo or more; most of the leaves alternate. — (Gk. hemi = half, 

 zone = a girdle; the ray akenes are swollen on one side.) Hemlzonla 



MM. Leaves all entire, not spinulose-tipped; involucre bracts not spinulose- 

 tipped; disk flowers 1-6; ray flowers 4-6. 

 N. Bisk flowers 1-2, fertile; akenes slightly hairy; plant 2.5-20 era. high; 

 most of the leaves opposite, 2.5 or less long. W. C. — (Diminutive of 

 Hemizonia a related genus.) Hemizonella durandil 



NN. Disk flowers 5-6, sterile; akenes smooth; plant 15-75 cm. high; most 

 of the leaves alternate, 5 cm. or less long. E. — (Gk. lagos = a rabbit, 

 phyllon = a leaf. Application not clear.) Lagophylla ramosissima 



LL, Pappus present at least on the disk akenes, of 7-12 scales which are often 

 awn-tipped. 

 O. Upper leaves spinulose- or gland-tipped; pappus of 7-12 scales, in i whorl, 

 often awn-tipped, its scale portion 3 ram. or less long. (See M.) Hemizonia 

 00. Leaves neither spinulose- nor gland-tipped; pappus of about 10 scales, 

 in 2 whorls, not awn-tipped, inner whorl about 6 mm. long. U. — (Gk. 

 ackyron = chaff, achaino = an akene; probably referring to the chaff-like 

 pappus.) Achyrachaena mollis 



GG. Pappus of 2-6 stout retrorsely-barbed awns; heads 0.8-10 cm. wide. 



BIDENS (p. 228) 



BB. Rays white or pink. 



P. Involucre bracts almost flat, not inclosing the ray akenes; leaves narrowly linear, 



margins involute or revolute; heads 12-30 mm. wide; rays 3-6. E. — (Gk. ft^e- 



pharon = an eyelash; -I- pappus.) Blepharlpappus 



PP. Involucre bracts boat-shaped, inclosing each an outer or ray akene. 



Q. Heads 12-25 mm. wide; rays 8-13; basal leaves often laciniately lobed or in- 



■ cised. E. — (Meaning not determined.) Layia glandulosa 



QQ. Heads 4-12 mm. wide; rays 1-7; leaves all entire or nearly dentate. (SeeM.) 



Hemizonia 

 AA. Heads rayless, i.e., without ligulate flowers, 



R. Pappus none; heads few-flowered; flowers yellow or greenish, the starainate and 

 pistillate often in separate heads; fruit often burlike. ' 



S. Leaves broadly lanceolate or wider, o^ten lobed or pinnatifid; heads staminate 

 or pistillate or with both kinds of flowers. 

 T. Involucre neither tubercled nor spiny; fruit not a bur; staminate and pistillate 

 flowers in the same head; plant merely puberulent or scabrous; lower leaves 

 opposite. E. — (Named from Ajuga iva, a plant with a similar odor.) 



Iva (marsh elder) 

 XT. Involucre of pistillate heads either tubercled or spiny, making fruit rough or 

 burlike; staminate and pistillate flowers in separate heads; plant either hairy 

 or all the leaves alternate. 



F. & R. EL, TfL. — IS 



