718 EUPHORBIACEAE 



umbel whorled : bracts ovate to linear, green : involucres mostly terminal, less than 2 mm. 

 long, bearing 4 or 5 yellowish green oblong glands subtended by white petal-like cuneate or 

 orbicular-cuneate appendages : capsules erect, subglobose, 3-4 mm. in diameter : seeds 

 smooth, sparingly pitted. [Euphorbia corollata L.] 



In dry soil, Ontario to Minnesota, Massachusetts, Kansas, Florida and Texas. Spring to fall. 



14. Tithymalopsis paniculata (Ell.) Small. Perennial, deep green. Stems often 

 solitary, erect, 3-9 dm. tall, simple below, pubescent, especially about the nodes, the umbel 

 3-5-rayed, the rays more or less extensively forked : leaves alternate below the whorl, sub- 

 tending the umbel ; blades oblong to oval, 2-6 cm. long, obtuse, glabrous or hairy along 

 the midrib and pale green beneath, somewhat revolute, abruptly narrowed or truncate at 

 the base, short-petioled or nearly sessile : involucres rather crowded in loose terminal clus- 



In sandy soil, North Carolina to Georgia. Summer. 



28. TITHYMALUS Adans. 



Annual or perennial herbs or shrubby plants, with simple or branched stems, which are 

 topped by several-rayed umbel-like cymes. Leaves below the umbel usually scattered or 

 alternate, without stipules : blades often broadened upward. Bracts of the umbel quite 

 different from the stem-leaves : blades entire or toothed. Involucres sessile or peduncled, 

 axillary, disposed in open or close cymes : lobes often toothed. Glands 4, transversely 

 oblong, reniform or crescent-shaped by the horn-like appendages, the missing one repre- 

 sented by a thin often ciliate lobe. Capsule exserted, smooth or tuberculate : lobes 

 rounded, sharp or keeled. Seeds variously pitted, often with caruncles. SPURGE. 



Leaf-blades entire : glands of the involucre crescent-shaped, reuiform or truncate. 



Leaves of the stem or main branches opposite. 1. T. Lathyris 



Leaves alternate. 



Bracts or leaves of the rays opposite : rays dichotomous. 

 Glands of the involucre without horn-like processes. 



Glands with erose-crumpled edges. 2. T. sphaero^pirmu. 



Glands entire or merely undulate. 

 Bracts of the ravs longer than broad. 



Stem-leaves linear to linear-lanceolate. 3. T. inundatus. 



Stem-leaves obovate to oblanceolate. 4. T. tclephioides. 



Bracts of the rays fully as broad as long. 5. T. Darlinijtonli. 



Glands of the involucre crescent-shaped by horn-like processes. 



Seeds smooth. 6. T. HeUeri. 



Seeds variously pitted. 



Surfaces of the seeds rather finely and irregularly pitted. 



Bracts of the rays very inequilateral, longer than the internodes. 7. T. longicuris. 

 Bracts of the rays equilateral, shorter the internodes. 



Stem-leaves with spatulate to ovate blades : bracts ovate-reni- 



form: seeds pitted. 8. T. commutatus. 



Stem-leaves with linear blades: bracts deltoid: seeds reticulated. 9. T. austnna. 

 Surfaces of the seeds longitudinally grooved or with large pits in 



longitudinal rows. 



Capsules with prominently keeled lobes. 10. T. Peplus. 



Capsules with rounded lobes. 



Seeds with 2 grooves on the inner face. 11. T. Peplidion. 



Seeds with several pits on the inner face. 12. T. tetraporus. 



Bracts or leaves of the rays alternate : rays trichotomous. 13. T. trichotomus. 



Leaf-blades serrulate. 



Glands of the involucres furnished with 2 horn-like appendages. 14. T, Roemerianus. 



Glands of the involucres transversely oblong, unappendaged. 

 Capsules warty. 



Stem-leaves with cordate or truncate bases. 15. T. obtusatus. 



Stem-leaves with narrowed bases. 



Upper stem-leaves merely sessile : bracts of the umbel manifestly longer 



than broad. 16. T. Arkansanus. 



Upper stem-leaves with small basal lobes : bracts of the umbel about 



as broad as long or broader. 17. T. Missouriensis. 



Capsules smooth. 18. T. leiococcits. 



1. Tithymalus Lathyris (L. ) Hill. Annual or biennial, glabrous, glaucous. Stem 

 usually erect, stout, 2-10 dm. tall, mostly simple below, umbellately branched above: 

 leaves numerous, mostly opposite, the lower with linear reflexed blades, the upper with lance- 

 olate or linear-lanceolate blades, 3.5-12 cm. long, these entire, sessile, subcordate at the 

 base : bracts of the rays opposite, ovate or ovate-lanceolate, truncate or subcordate : in- 

 volucres 5 mm. long, bearing 4 crescent-shaped unappendaged glands prolonged into short 

 horns : capsules subglobose, 10-12 mm. in diameter, the lobes rounded : seeds oblong-ovoid, 

 5-6 mm. long, terete, usually wrinkled, dirty-brown. [Euphorbia Lathyris L.] 



In waste places, New Jersey to North Carolina and Texas. Also in California. Native of Europe. 

 Spring and summer. 



