Pe a ee 
‘ 
Compositaceae 399 
AA. Leaves cordate or ovate; without spine at base. 
B. Body of mature bur 2.5—-3 cm. long; spines about 100, stiff, strongly hooked, 
about half as long as the body of the bur. E. 
X. speciosum. Kearn. 
BB. Body of mature bur |.5——-2 cm. long. 
Creeopmes 50—/0. - 
D. Spines about 70, about '4 as long as the diameter of the body of the ovate 
mature bur. E. (Apparently X. canadense for our region.) 
X. varians Gr. 
DD. Spines about 50, about 2/3 as long as the diameter of the body of the 
oblong or slightly ovate mature bur. E. (Apparently X. strumarum for our 
region. ) X. affine Gr. 
CC. Spines about 20, about as long as the body of the narrowly oblong bur. E. 
X. oligacanthum Pip. 
RUDBECKIA CONH-FLOWER 
Coarse, often rough. Leaves alternate, entire to pinnatifid. Heads rayless or ra- 
diate, large, on long peduncles, solitary, in the axils or terminal; involucre-bracts imbri- 
cated in 2—4 series; receptacle conic or convex. Ray-flowers yellow or none, neutral, 
entire or toothed. Disk-flowers purple or brown, perfect, fertile, 4-lobed. Akenes 4-an- 
gled, obtuse or truncate. Pappus none or a crown of 2—4 short teeth. (Honor of C. 
Rudbeck, a Swedish botanist.) 
A. Rays present. 
. B. Leaves stiff-hairy; pappus none; disk globose-ovoid. W. 
BR. hirta L. (Black-eyed Susan) 
BB. Leaves finely soft-hairy; pappus of 4 irregular bract-like teeth; disk columnar. 
ee R. californica Gray (Mexican Hat) 
AA. Rays none. 
C. Plant pubescent; leaves mostly 3—5-parted toward the base. E. 
R. alpicola Pip. 
CC. Plant glabrous or nearly so, somewhat glaucous; leaves entire or dentate. E. 
R. occidentalis Nutt. (Nigger-thumb) 
BALSAMORHIZA BALSAM-ROOT 
Perennial, low, with scape-like or few-leaved stems; roots thick, resinous. Leaves 
opposite or alternate, mostly basal, entire to 2-pinnate. Heads radiate, many-flowered, 
large, 1—7 on a stem; involucre-bracts somewhat imbricated, the outer herbaceous or 
foliaceous; receptacle flat or barely convex. Ray-flowers pistillate, fertile, yellow: akenes 
flattened parallel to the bracts, oblong. Disk-flowers perfect, yellow: akenes prismatic, 
4-angled, somewhat flattish. Pappus none. (Gk. balsamon—balsam, rhiza=root; the 
root is aromatic.) 
A. Leaves entire to serrate; stems with |—7 heads. 
B. Ray-corolla 2—2.5 cm. long, persistent to the akenes; akenes all canescent. E. 
B. careyana Gray 
BB. Ray-corollas 2.5—5 cm. long, deciduous from the akenes; akenes all glabrous. 
C. Plant silvery-canescent; involucre woolly; stem-leaves linear to spatulate. E. 
B. sagittata Nutt. 
CC. Plant green tho pubescent to glabrate; involucre not woolly or only so at 
base; stem-leaves lanceolate. W. E. B. deltoidea Nutt. 
i AA. Leaves laciniately lobed to 2-pinnatifid; stems with only | head. 
D. Plant green, glabrous or somewhat hairy. 
