^6 CXXI. EUPHORBIACEiE. • Euphorbia. 



Conspectus of the Genera. 



i Fruit in a toothed, leafy involucre. Acalypha. 2 



{8— 16-androus. { Fruit not involucrate Crolon. 5 



polyandrous. Leaves large, glaucous, peltate. Ricinus. 3 



tetrandrous. Leaves evergreen, ov te Buxus. 7 



peniandrous. Leaves clothed with shining scales. Crotonopsis. 4 



triandrous. Leaves very small . . . Phyllanthua. 6 



monandrous, several in a corolla-like involucre Euplwrbia. 1 



1. EUPHORBIA. 



Euphorhus, physician to Juba, king of Mauritiana, first used these plants in medicine. 



Flowers c? , mostly achlamydeous ; involucre monophyllous, sub- 

 campanulate, with 4 — 5 petaloid segments alternating with as many 

 external, gland-like teeth. J* 12 or more ; stamen 1 ; filament articu- 

 lated in the middle. 9 solitary, central ; ovary pedicellate ; styles 

 3, bifid ; capsule 3-lobed, 3-celled ; cells 1 -seeded. — Herbs or shrubs^ 

 with a milky juice. Lvs. generally opposite^ sometimes wanting^ often 

 stipulate. Iiivol. axillary or subuvibellate. 



* Heads ofjlowers in involucrate umbels, f Cauline leaves alternate. 



1. E. COROLLATA. Flowering Spurge. 



Erect; cauline ^nd floral lvs. oblong, narrow, obtuse; inn^r segments of the 

 invol. obovate, petaloid ; umbel 5-rayed, rays 2 or 3 times di- or trichotomous. — 

 % In dry fields, &c., Can. and U. S. Stem slender, erect, 1— 2f high, generally 

 simple and smooth. Leaves 1 — 2' long, often quite linear, very entire, scat- 

 tered on the stem, verticillate and opposite in the umbel. The umbel, as in 

 other species, consists of about 5 verticillate branches from the summit of the 

 stem, each of which is subdivided into about 3, and finally into 2 peduncles. 

 Corolla-like involucre large, white, showy. July Aug. — The central head is 



2 or 3 weeks earliest. 



2. E. HELIOSCOPIA. SU7l SpUTgC. 



Erect ; floral lvs. obovate, caulme wedge-form, serrate, smooth ; umbel 5- 

 rayed, then 3-rayed and forked. — A milky weed in cultivated grounds, N. 

 H. ! to Niagara ! S. to Car., remaikable for the symmetry of its vegetation. 

 Stem smooth, erect, 8 — 16' high. Leaves scattered, f — 1^' long, | as broad at 

 the rounded or retuse apex, finely and sharply serrate, entire, and tapering to 

 the base. Umbels subtended by a large involucre of 5 obovate leaves. Each 

 of the 5 rays is pilose with scattered hairs and subdivided into an umbellet of 



3 rays with a 3-leaved involucel, and these finally into 2 or more pedicellate 

 fascicles. Capsules smooth. June, July. 



3. E. NEMORALis. Darl. (E. pilosa. Pursh.) Hairy Spu/rge. 



Leaves oblong-lanceolate and oblanceolate, acute, narrowed to the base, 

 subsessile, pilose beneath, those of the involucre ovate; umbel 5 — 8-rayed, rays 

 ones or twice divided; seg. of the floral invol. colored, entire, subreniform; ova. 

 verrucose. — % Moist woods. Can. to Va. Stem 2 — 3f high, smooth, rarely 

 branched below the umbel. Leaves 3 — 4' by 1', entire or slightly serrulate 

 above, those of the stem alternate, of the branches opposite and nearly as broad 

 as long. Floral involucre purplish-brown within. * Capsule at length nearly 

 smooth. May, June. 



4. E. OBTUSATA. Pursh. Obtuse-leaved Spurge. 



Erect; lvs. alternate, .sessile, spatulate, serrulate, smooth; U7nbel 3-rayed, 

 rays twice dichotomous; 7?<?r«nr5. ovate, subcordate, somewhat obtuse; caps. 

 muricate. — % Grows in w^aste grounds, Can. to Va. Stem 12 — 18' high. 



5. E. Peplus. 



St. erect or ascending, branched below ; umbels 3-rayed, rays mostly di- 

 chotomous; involucrate Iv.'^. ovate, acute. — (f) A small species, in cultivated 

 grounds, Penn. to Va. Floral leaves large. Flowers conspicuous. Torr. 

 t Cauline leaves opposite. 



6. E. MerccrialIna. Muhl. 



5"/. weak and slender, .'imply 3-clcft; /<••.<;. opposite and tcrnately verti- 



