ORDER 112. EUPHORBIACE^E. 625 



but loses its deleterious properties by washing and exposure to heat. Castor-oil is expressed 

 from the seeds of Ricinus communis. Croton-oil from the seeds of Croton Tigliuin. Caoutchouc 

 is yielded in abundance by several S. American species. 



FIG. 687.1. Head or capitulum of Eu- 

 phorbia corollata; with the corolla-like in- 

 volucre, and pedicellate pistillate flower. 

 2. The involucre tube cut open, showing 

 >/ the monandrous, staminate flowers sur- 

 jC; rounding the pistillate. 3. One of tho 

 S \W & flowers, with a toothed bract at base. 4. 

 It Cross section of the ovary, showing the 3 



one-seeded cells or carpels. 

 Obs. Our specimens of the Euphorbiacea? were submitted to the inspection of Dr. Engclmann, 

 of St. Louis, and are here described nearly in accordance with his nomenclature. 



GENERA. 

 Cells of the ovary one-ovuled ; fruit 3 (rarely 2 or l)-seeded. (*) 



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



? flower, an ovary exserted on a pedicel. EUKHOEBIA. 1 



* Flowers not in an involucre 3 , all apetalous, having a calyx only, (a) 



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



a Flower 2 to 3-androus, in racemes. Plants hairy or downy TUAGIA. 3 



a Flowers 8 to 12-androns, in small spikes with large bracts ACALYPJIA . 4 



a Flowers 10 to 15-androus, in cymes, with white sepals. Stinging CSIDOSCOLCS. 5 



a Flowers polyandrous, in panicles ; fruit echinate. Plant glabrous RICIXUS. 6 



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



b Ova. 3 (rarely 2)-celled and seeded. Fls. clustered. Woolly, downy or scurfy.CnoTOX 7 

 b Ova. 1-celled, 1 -seeded, indehiscent. Fls. axillary, small. Silvery scurfy. CBOTOXOPSIS. 8 

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



C Calyx G-parted ; stamens 3, united. Flowers axillary, small PiiYLLAtrnirs. 9 



C Calyx 4-parted ; stamens 4, distinct, large. Flowers in bracted spikes PACHYSAXDRA. 10 



C Calyx 4-parted ; stamens 4, distinct. Flowers axillary. Shrub. Leaves opposite.. Buxtrs. 11 



1. EUPHOR'BIA, L. (Named for Euphorbus, physician to Juba, 

 King of Mauritania.) SPURGE. Flowers 8 , several in an involucrate 

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

 alternate with as many large glands ; flowers 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. 



Stems spiny, thick, erect. Stipules none. Floral leaves scarlet No. 1 



| Steins imarmed, erect. Leaves destitute of stipules, alternate or opposite'. (*) 



* Involucre with 4 or 5 glands which are 2-horned or crescent-shaped, i^a) 



a Umbel of many rays. Stem-leaves narrow, alternate. Seeds smooth. 11 Nos. 2. ?, 



a Umbel of 3 rays, and forked. Stem leaves alternate, thin Nos. 4, 5 



a Umbel of 3 or 4 rays, and forked. Stem leaves opposite, thick No. 



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



b Heads nearly sessile. Leaves with broad, white margins No. 7 



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



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



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



C Inflorescence in compound cymes, with long peduncles No. 12 



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



d Seeds reticulated or wrinkled. Leaves serrulate Nos. 13. 14 



d Seeds smooth and even, in a rough, warty fruit Nos. 15, 16 



C Inflorescence solitary, axillary. Leaves all opposite No. 1 



C Inflorescence a simple, terminal cluster. Leaves alternate or opposite y 



Stems unarmed, chiefly prostrate, diffuse. Leaves all opposite, small. Avith small, 



entire or cleft stipules. Involucres axillary or cluttered. 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, 2o, 24 



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



1 E. splendens Bojaris. St. suffruticous, fleshy, armed witb rigid, sharp 

 thorns ; Ivs. ovate, tapering to the base, glabrous, entire, acute, mucronate ; ped. 

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

 date, scarlet. A singular and showy garden plant, f Madagascar. 



40 



