¥h 



EUPHORBIACEAE. 



Vol. II. 



3. Chamaesyce serpens (H.B.K.) Small. Round-leaved Spreading Spurge, 



Fig. 2734. 



Euphorbia serpens H.B.K. Nov. Gen. 2: 52. 1817. 

 Chamaesyce serpens Small, Fl. SE. U. S. 709. 1903. 



Annual, pale green, glabrous, sometimes glau- 

 cescent. Stem branched from the base, the slen- 

 der or filiform branches prostrate, 2'-i2' long; 

 leaves orbicular, orbicular-ovate or oval, i"-3" 

 long, obtuse or emarginate, entire, often slightly 

 revolute-margined, short-petioled, the base ob- 

 lique, rounded or subcordate ; stipules triangular, 

 somewhat incised at the apex; peduncles slightly 

 longer than the petioles; involucres solitary in 

 the axils, nearly i" high, bearing 4 sessile saucer- 

 shaped glands shorter than the lobes, each sub- 

 tended by a minute irregular crenulate append- 

 age; capsule nodding, depressed-globose, i" in 

 diameter ; seeds oblong-ovoid, 4" long, smooth, 

 obtusely 4-angled, light gray. 



Illinois to Iowa, western Ontario, South Dakota 

 and Kansas, south to Mexico. West Indies. In bal- 

 last about the eastern seaports. March-Oct. 



4. Chamaesyce petaloidea (Engelm.) 



Small. White-flowered Spurge. 



Fig- 2735- 



Euphorbia petaloidea Engelm. Bot. Max. Bound. 



Surv. 185. 1859. 

 C. petaloidea Small, Fl, SE. U. S. 711. 1903. 



Annual, pale green, glabrous. Stem usually 

 rather stout, erect, branched above, 6'-2° high ; 

 leaves opposite, linear, oblong or linear-lanceo- 

 late, 5"-i' long, obtuse, usually flat, straight, 

 entire, slender-petioled ; stipules a fringe of setae; 

 involucres solitary in the axils, oblong-campanu- 

 late, i" long, bearing 4 wineglass-shaped glands 

 about as long as the lobes, each subtended by a 

 white ovate or orbicular entire or undulate ap- 

 pendage; peduncles as long as the involucres; 

 capsule globose-reniform, i" long; seeds oblong- 

 ovoid, nearly 1" long, ash-colored, minutely 

 pitted, nearly terete. 



Prairies, Iowa to Wyoming, Missouri, Texas and 

 Arizona, July-Sept. 



5. Chamaesyce zygophylloides (Boiss.) 

 Small. Prairie Spurge. Fig. 2736. 



Euphorbia petaloidea var. Nutfallii Engelm. Bot. Mex. 



Bound. Surv. 185. 1859. 

 E. -ygophylloides Boiss. Cent. Euph. 10. i860. 

 Euphorbia arenaria Engelm. & Gray, Bost. Journ. Nat. 



Hist. 5; 260. 1847. Not Nutt. 1837. 



Annual, bright green, glabrous. Stem slender, erect 

 or ascending, branched, 4'-^° high, the branches 

 wiry, leaves mostly linear and mucronulate or trun- 

 cate at the apex, often involute, obtuse or narrowed 

 at the base, petioled, usually curved, the midvein 

 prominent; stipules lanceolate or subulate-lanceo- 

 late ; involucres solitary in the axils, campanulate, 

 less than i" long, long-peduncled, bearing 4 saucer- 

 shaped glands subtended by white entire oblong or 

 ovate appendages ; seeds ovoid, i" long, gray, 

 4-angled. 



Prairies, Missouri and Kansas to Texas and Mexico. 

 June-Sept. 



