486 CXXI. EUPHORBlACEiE. Euphorbia. 



Conspectus of the Genera. 



, Fruit in a toothed, leafy involucre. 



f 8— 16-anclrous. ( Fruit not iuvolucrate. 



polyanclrous. Leaves large, glaucous, peltate. 

 J tetrandrous. Leaves evergreen, ov rte. 

 ] peulandrous. Leaves cloihed with shining scales, 

 triandrous. Leaves very snaall. .... 

 Sterile fla. Imonandrou3, several in a corolla-like involucre. 



Acalypha. 2 



Croton. 5 



Ricinus. 3 



Buxua. 7 



Crotonapsis. 4 



Phyllanthus. 6 



Euphorbia. \ 



1. EUPHORBIA. 



Euphm-hus, physician to Juba, king of Mauritiana, first used these plants in medicine. 



Flowers S , mostly achlaraydeous ; involucre monophyllous, sub- 

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

 external, gland-like teeth, c? 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. Invol. axillary or subumbellate. 



* Heads of flowers in i?ivohicrate uvibels. f Cauline leaves alternate. 



1. E. COROLLATA. Flotvering Spurge. 



Erect; cauline a.nd floral lvs. oblong, narrow, obtuse; inner segments of the 

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



01 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. Sun Spurge. 



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

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

 H" ! to Niagara ! S. to Gar., remarkable for the symmetry of its vegetation. 

 Stem smooth, erect, 8 — 16' high. Leaves scattered, § — IJ' 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 Spurge. 



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 flora.l invol. colored, entire, subreniform ; ova. 

 verruco.se. — % Moist woods. Can. to Va. Stem 2— 3f high, smooth, raiely 

 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 pm'plish-brown within. Capsule at length nearly 

 smooth. May, June. 



4. E. obtusata; Pursh. Obtuse-leaved Spurge. 



Erect ; Im. alternate, sessile, spatulate, serrulate, smooth ; umbel 3-rayed, 

 rays twice dichotomous ; floral Irs. ovate, subcordate, somewhat obtuse ; caps, 

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



5. E. Peplus. 



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

 chotomous; iuvolucrate lvs. ovate, acute. — (T) A small species, in cultivated 

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

 t Cauline leaves opposite. 



6. E. Mercurialina. Muhl. 



S^. weak and slender, simply 3-cleft; lis. opposite and ternately verti- 



