90 
Spring Flora of Oklahoma 
shaped bracts; stamens 2 or 3. 
IV. Stillingia. 
Flowers in cymes; calyx corolla-like, salver-form. 
V. Cnidoscolus. 
Flowers in an involucre, the calyx represented by a 
minute scale at the base of the filament-like pedicel. 
Glands of the involucres with petal-like appendages, 
these sometimes much reduced. 
Leaves all opposite. VI. Chamaesyce. 
Leaves alternate or scattered at least below the 
inflorescence. 
Annual or biennial; stipules narrow; bracts 
petal-like. VII. Dichrophyllum. 
Perennial; stipules none; bracts not petal-like. 
VIII. Tithymalopsis. 
Glands of the involucres without petal-like appen¬ 
dages, entirely naked, sometimes with crescent¬ 
like horns. 
Stem topped by an umbel; stipules none; involu¬ 
cres in open cymes, each with four glands and 
entire or toothed lobes. IX. Tithymalus. 
Stem not topped by an umbel; stipules gland¬ 
like; involucres in cluster-like cymes, each 
with a single gland or rarely 4 glands and 
fimbriate lobes. X. Poinsettia. 
I. PHYLLANTHUS L. 
Annual, biennial or perennial herbs. Stems wiry. 
Leaves alternate, entire. Flowers monoecious, apetalous, 
a staminate and pistillate one together in the axils. Sta¬ 
mens usually 3, the filaments more or less united, rarely 
separate. Ovary 3-celled. Ovules 2 in each cavity. 
Styles 3. each 2-cleft. Capsule globose. 
