386 EUPHORBIACE^E. (SPURGE FAMILY.) 



glands at its sinuses. Sterile flowers numerous and lining the base of the invo- 

 lucre, each from the axil of a little bract, and consisting merely of a single star 

 men jointed on a pedicel like the filament: anther-cells globular, separate. 

 Fertile flower solitary in the middle of the involucre, soon protruded on a long 

 pedicel, consisting of a 3-lobed and 3-ceIled ovary with no calyx, or a mere ves- 

 tige. Styles 3, each 2-cleft; the stigmas therefore 6. Pod separating into 3 

 one-seeded carpels, which split elastic-ally into 2 valves. Seed often caruncled. 



Plants (herbs in the United States), with a milky acrid juice, the uppermost 

 leaves often in whorls or pairs. Peduncles lateral or terminal, often umbellate- 

 clustered. (Named after Euphorbus, physician to King Juba.) 



For the following elaboration of the genus I am indebted to DR. ENGELMANN. 



$ 1. Leaves (all opposite and similar, small) furnished with awl-shaped or scaly stip- 

 ules: stems much branched: involucres solitary in the forks or axils, sometimes 

 crowded or clustered on the branchlets : root annual in all our species : plants /lower- 

 ing all the summer and autumn. (Stipulate.) 



# Seeds smooth and even, ash-colored : leaves entire, glabrous, as is the whole plant, 

 and pale or slightly glaucous. 



1. E. polygonifdlia, L. (SHORE SPURGE.) Prostrate-spreading; 

 leaves oblong-linear, obtuse, mucronate, slightly cordate or obtuse at the oblique 

 base (4" - 8" long) J peduncles equalling the short petioles ; glands of the invo- 

 lucre minute, not appendaged ; pod obtusely angled; seeds ovate (1" long, the 

 largest of this section). Sandy shore of the Atlantic and of the Great Lakes. 



2. E. Oeyeii, Engelm. Procumbent; leaves oblong-ovate, obtuse at the 

 apex and the oblique base ; peduncles equalling the petioles ; appendages of the 

 involucre petal-like (white), orbicular; p'od acutely angled; seeds obtusely tri- 

 angular (I" long). Sandy soil, Beardstown, Illinois (Geyer), and southwest- 

 ward. This is a small-seeded form (var. microsperma) : other forms in Mis- 

 souri and Texas have larger petal-like appendages and larger seeds. 



3. E. lieriliarioitlcs, Nutt. Prostrate ; leaves round-ovate, obtuse al 

 the base (only |"-2^" long) ; peduncles much longer than the petioles, lateral, sin- 

 gle or clustered ; appendages of the involucre minute and crenulate, or none ; pod 

 acutely angled; seeds obtusely angled (" long). Banks of the Mississippi 

 and lower Ohio, in rich alluvial soil, and southwestward. 



* * Seeds minutely roughened, ash-colored: leaves serrulate, hairy. 



4. E. till Illi Strata, Engelm. mss. Procumbent, puberulent or hairy ; 

 leaves elliptical with an oblique obtuse base, serrulate towards the apex, sparse- 

 ly hairy underneath ('-f long, somethnes with a brown spot above) ; pedun- 

 cles rather shorter than the petioles, crowded in lateral clusters ; involucre cleft 

 on the back, its appendages orbicular or truncate and nearly entire ; pod acute- 

 ly angled, puberulent; seeds ovate, 4-angled (|" long). "With the last. 



Branches 6' -20' long. Distinguished from the next by its broader leaves, 

 slit involucre, and rounder, granulated (not transversely grooved) seed. 



* * * Seeds transversely wrinkled-pitted: leaves serrate, often hairy and falcate. 



5. E. maculata, L. (SPOTTED SPURGE.) Pnstrate; leaves very- 

 oblique at the base, oblong-linear (4" - 6" long), serrulate towards the apex, 



