Ori>er 112.— KUPHORBIAOB^. 625 



\mt loses its <IoIet«rions proporti«9 by wauhing and expoauro to heat, Ca«toT-oIl is expressed 

 from the sec<ls uf liicinus coinmunia. Croton-oU from the seeila of Croton TigUuui. Caoutcliouo 

 is yielded In abtiudaoco by several S. Amcricaa species. 



Fia. 697.— 1. Head or capltulnm of Eu- 

 phorbia coruUata; with the corolla-like in- 

 volucre, and pedicellate pistillate flower. 

 2. The involucre tube cut open, sbowlns 

 J the monandrous, staniinate flowers snr- 

 yl rounding the pistillate. 8. One of the 

 f// $ flowers, with a toothed bract at base. 4. 

 If/ Cross section of the ovary, showing the 3 

 one-seeded cells or carpels. 

 Oba. Our apeclmens of the Euphorbiacore were submitted to the inspection of Dr. Engelmann, 

 ef St. Loais, and are hero described nearly in accordance with his nomenclature. 



GENERA. 

 S Cells of the ovary ono-ovulod ; frnit 3 (rarely 2 or l)-scedcd. (*) 



* Flowers in a cup-shaped Involucre, the $ many, each merely a stamen, with one 



9 flower, an ovary exsertod on a pedicel Ecphordia. 1 



* Flowers not in an involucre s, all apetalous, having a calyx only, (a) 



a Flowers diandrous, in a terminal spike. Plants glabrous Stillingia. 2 



a Flower 2 to 3-androua, in racemes. Plants hairy or downy Tracia. Jl 



a Flowers 3 to 12-audrous, in small spikes with largo bracts Acalypiia . 4 



a Flowers 10 to 15-androu8, in cymes, with white sepals. Stinging. , . .Cnidoscolus. ^ 

 a Flowers polyandrous, in panicles ; fruit echinate. Plant glabrous Eicinns. fi 



* Flowers not In an involucre 8 , the sterile and often the fertile, also with petals, (b) 



b Ova. 8 (rarely 2)-celled and seeded. Fls. clustered. Woolly, downy or scurfy.CROTos. 7 

 b Ovii. 1-celled, l-seeded, indehiscent. Fls. axillary, small. Silvery scurfy. Croton opsis. 8 

 S Cells of the ovary 2-ovuled ; fruit 6 (or abortively fewer)-seeded. (c) 



C Calyx 6-parted ; stamens 8, nntted. Flowers axillary, small PnYLLANxiius. 9 



c Calyx 4-parted ; stamens 4, distinct, large- Flowers in bracted spikes. . ..Paciiysandra. 10 

 C Calyx 4-parted ; stamens 4, distinct. Flowers asillary. Shrub. Leaves opposite. . Buxus. 1 1 



1. EUPHOR'BIA, L. (Named for Euphorbiis^ physician to Juba* 

 King of Mauritania.) Spurge. Flowers 8 , several in an involucratc 

 cluster ; involucre calyx-like, cup-sliaped, with 4 or 5 petaloid segments 

 alternate with as many large glands ; f owers achlamydeous, the ^ 12 

 or more each consisting of a single stamen on a pedicel which is axil- 

 lary to a little bract ; $ flower solitary, central, a 3-carpeled, 3-styled 

 and 3-seeded ovary raised on a slender pedicel ; capsule 3-lobed, separ- 

 ating into 3 bivalved nutlets. — Herbs or shrubs with a milky juice. 

 Lvs. generally opposite or verticillate, often alternate, sometimes none. 

 Involucres flower-like, axillary or umbellate. 



§ Sterna spiny, thick, erect.— Stipules none. Floral leaves scarlet No. 1 



5 Stems unarmed, erect. Leaves destitute of stipules, alternate or opposite. (*) 



* Involucre with 4 or 5 glands which are 2-horncd or crescent-shaped, (a) 



a Umbel of many rays. Stem-leaves narrow, nlternato. Seeds smooth, u Nos. 2, 3 



a Umbel of 8 rays, and forked. — Stem loaves alternate, thin Kos. 4, 5 



a Umbel of 8 or 4 rays, and forked.— Stem leaves opposite, thick No. C 



* Involucre with 5 white, petal-like glands or appendages, (b) 



b Heads nearly sfessile. Leaves with broad, white margins No. 1 



b Heads pedunculate, solitary or subpaniculate. Leaves broad oval Nos. 8,9 



b Heads pedunculate, umbellate. Leaves oblong, mostly narrow Nos. 10, 11 



* Involucre with 1 to 5 glands neither petal-like nor horned, (c) 



c Inflorescence in compound cymes, with long peduncles No. VI 



o Inflorescence in compound umbels, with short peduncles, (d) 



d Seeds reticulated or -wrinkled. Leaves serrulate Nos. 13, 1-1 



d Seeds smooth and even, in a rough, warty fruit Nos. 15, Iti 



c Inflorescence solitary, axillary. Leaves all opposite ■ No. 17 



Inflorescence a simple, terminal cluster. Leaves alternate or opposite Nos. IS, 19 



5 Stems unarmed, chiefly prostrate, diffuse. Leaves all opposite, small, with small, 



entire or cleft stipules. Involucres axillary or clustered. May to Nov. (T) (e) 

 e Leaves serrulate or serrate. Seeds roughened with wrinkles or pits, (f ) 



f Stem ascending or erect, smooth or smoothish. Seeds black or amber color. Nos. 20, 21 



f Stem prostrate, hairy or puberulent as well as the leaves and fruit Nos. 22, 23, 24 



e Leaves entire. Seeds smooth and even. Plants glabrous Nos. 25, 26, 27 



1 E. spl^ndena Bojaria. St. suffruticous, fleshy, armed with rigid, sharp 

 thorns ; lvs. ovate, tapering to the base, plabrous, entire, acute, mucronate ; pcd. 

 axillary, 2 or 3 times dichotomous ; floral lvs. in pairs, broader than long, cuspi- 

 date, scarlet. — A eingular and showy garden plant, f Madagascar. 



40 



