Euphorbiaceae 245 

EUPHORBIACEAE Spurge Family 
Herbs (ours) or shrubs or trees; juice acrid, often milly. Leaves alternate or op- 
posite or whorled; stipules present or none. Flowers monoicous or dioicous, variously 
arranged, mostly naked or with the calyx present or represented by a scale at the base of the 
stamens ; in Euphorbia subtended by an involucre resembling a calyx. Stamens |—many. 
Ovary |—3-celled; its cells |—2-ovuled: styles as many as ovary-cells, simple or divided 
or many-cleft. Fruit a capsule, 2—3-celled, dehiscent. 
A. Flowers involucrate; stamens usually 1; both staminate and pistillate flowers with 
only a rudimentary calyx or none at all; capsule 3-celled; cells each with | or more 
| seeds. EUPHORBIA (p. 245) 
' AA. Flowers not involucrate; stamens 6—7; staminate flowers with a 5—6-parted 
calyx, pistillate flowers naked; capsule |-celled, |-seeded. PiscARIA (p. 245) 
EUPHORBIA SPURGE 
Leaves alternate or opposite or whorled. Flowers small, usually monoicous, naked, 

subtended by a top-shaped or campanulate involucre. Staminate flowers numerous, of | 
naked stamen jointed upon a short pedicel which usually has a minute bract at the base. 
Pistillate flowers solitary, pedicelled, soon exserted. Ovary 3-celled, 3-ovuled: styles 3, 
rusually 2-cleft. (Honor of Euphorbus, the physician to King Juba.) 
A. Stems prostrate-spreading or nearly so; involucre-glands bearing petal-like append- 
ages. 
B. Plant pubescent; seed black. E. 
| E. maculata L. (Milk Spurge) 
BB. Plant glabrous; seed gray. ‘ 
C. Seed with 5—6 sharp transverse ridges; leaves linear-oblong to ovate. E. (E. 
greene. ) E. glyptosperma Engelm. (Ridge-seed Spurge) 
CC. Seed pitted and somewhat transversely wrinkled; leaves oblong to spatulate. 
W.E. CE. serpyllifolia consanguinea. ) 
E. serpyllifolia Pers. (Thyme-leaved Spurge) 





AA. Stems erect or nearly so; involucre-glands without petal-like appendages. 
CD. At least the upper leaves serrulate. 
E. Seed pitted; glands with horn-like projections. U. 
E. crenulata Engelm. 
EE. Seed reticulate; glands blunt. E. (EE. arkansana missouriensis. ) 
E. dictyosperma F. & M. (Net-seed Spurge) 
DD. Leaves entire. 
F. Leaves round-obovate; umbel 3-rayed. W. 
E. peplus LL. (Pretty ‘Spurge) 
FF. Leaves linear to oblong; umbel 4- to many-rayed. 
G. Seed usually wrinkled; leaves linear to oblong. W. 
E. lathyrus L. (Caper Spurge) 
GG. Seed smooth; leaves filiform. E. 
E. cyparissias L. (Cypress Spurge) 
PISCARIA. (Eremocarpus) 
Annual, low, heavy-scented, hoary thruout with very dense stellate pubescence (ours). 
Leaves alternate, entire, ovate (ours), petioled; stipules none. Flowers small, in axillary 
clusters, without an involucre, dioicous or monoicous. Calyx of staminate flowers 5—6- 
parted; calyx of the pistillate flowers none. Stamens 6—/: receptacle hairy. Ovary 

