ORDER 112. EUPHORBIACE^!. 62a 



bat loses its deleterious properties by washing and exposure to hont. Cnstor-oil Is expressed 

 from tlie seeds of liicinus communis. Crotoa-oil from the seeds of Croton Tigiiuui. Caoutchouc 

 is yielded iu abundance by several S. American speck's. 



FIG. 637.- 1. Head or capitulum of Eu- 

 phorbiacorollata; with the corolla-like in- 

 volucre, and pedicellate pistillate flower. 

 2. The involucre tube cut open, showing 

 J the monandrous, staminate flowers sur- 

 W, rounding the pistillate. 8. One of tho 

 }y t flowers, with a toothed bract at base. 4. 

 T Cross section of the ovary, showing the 3 



one-seeded cells or carpels. 



0'>*. Our specimens of the Euphorbiacea; were submitted to the inspection of Dr. Engelmann, 

 of bt. Louis, aud arc hero described nearly in accordance with his nomenclature. 



GENERA. 

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



* Flowers in a cup-shaped involucre, the & many, each merely a stamen, with ono 



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



* Flowers not in an involucre 8, all apetalous, having a calyx only, (a) 



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



a Flower 2 to 3-androus, in racemes. Plants hairy or downy TUAGIA. 8 



a Flowers 8 to 12-audrous, in small spikes with largo bracts ACALYPIIA . 4 



a Flowers 10 to 15-androus, in cymes, with white sepals. Stinging CNIDOSCOLUS. 9 



a Flowers polyandrous, in panicles ; fruit cchinate. Plant glabrous RICINUS. 6 



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



b Ova. 3 (rarely 2)-cellcd and seeded. Fls. clustered. Woolly, downy or scurfy.Cp.OTON. 7 

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

 | Cells of the ovary 2-ovuled ; fruit 6 (or abortively fewcr)-sceded. (c) 



C Calyx C-parted ; stamens 8, united. Flowers axillary, small PIITLLANTIIUS. 9 



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



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



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

 King of Mauritania.) SPURGE. Flowers 5* , 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-seedcd 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 unarmed, erect. Leaves destitute of stipules, alternate or opposite. (*) 



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



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



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



a Umbel <f 8 or 4 rays, and forked. Stem leaves opposite, thick No. 6 



* 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 with 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. 17 



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



$ 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 Stern ascending or erect, smooth or Emoothish. 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. splendens Bojaris. St. suffruticous, fleshy, armed with rigid, sharp 

 thorns ; Ivs. ovate, tapering to tho 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 



