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36 | MISSOURI BOTANICAL GARDEN. 
KEY TO SPECIES OF CROTON OF THE UNITED STATES. 
I. Staminate and pistillate flowers petaliferous. C. Alabamensis. 
II, Staminate flowers petaliferous; petals absent or rudimentary in 
pistillate flowers. 
A. Scaly. C. argyranthemus. 
B. Stellate. 
a. Shrub; margins of leaves entire or nearly so; the 5-parted pistil- 
late calyx not accrescent. 
1. Leaves ovate to ovate-lanceolate, cordate or rounded at base. 
Stamens 15 to 35; sepals stellate. C. Berlandieri. 
Stamens 10; sepals stellate. C. fruticulosus. 
Stamens 15; sepals glabrous. C. Sonorae. 
2. Leaves elliptical to oblong or lanceolate. 
Leaves elliptical, thickish, very densely stellate. C. suaveolens. 
Leaves oblong, discolor, stellate above and below. 
C. Torreyanus. 
Leaves oblong to lanceolate, glabrous above; racemes uni- 
sexual; capsules bristly pubescent, numerous. 
C. Cortesianus. 
8, Leaves elongated-oblong to linear. 
Leaves narrowly linear, glabrous above. _C. linearis, form A. 
Leaves elongated oblong, microscopically umbonate-stellate 
above. C. linearis, form B., 
b. Shrub, or annual; margins of leaves not entire, base biglandular; 
branches striate, except in C. betulinus; the 4- to 5-parted calyx 
accrescent. 
1. Shrub; leaves ovate, 1 to 2 cm. long. C. betulinus. 
2. Annual; leaves ovate, 2 to 4 cm. long. C. Miquelensis. 
8. Annual; erect, slender; leaves elliptical to lanceolate; calyx 
segments glabrate. C. Floridanus. 
4. Annual; leaves usually oblong, margins variously interrupted to 
almost entire. Varieties of C. glandulosus. 
Appressed stellate; low; leaves small, 1 to 2 cm., elliptical. 
C. glandulosus Lindheimeri. 
Thinly stellate; upper leaves oblong, entire or serrato-crenate. 
C. glandulosus Shorti. 
Densely stellate; low; leaves ovate, coarsely serrato-crenate. 
C. glandulosus Simpsoni. 
Coarsely stellate; upper leaves oblong, serrate. 
C. glandulosus septentrionalis. 
Thinly appressed stellate; upper leaves elongated-oblong, 
crenate. C. glandulosus crenatifolius. 
Thinly appressed stellate; upper leaves linear, distantly ser- 
rate C. glandulosus angustifolius. 
