180 EUPHOEBIACEAE. 



Leaves mainly opposite and decussate : capsules 10 mm. wide and more. 



1. T. Lathyrus. 

 Leaves alternate or scattered : capsules less than 10 mm. wide. 

 Leaf-blades serrulate : involucre with oblong, oval, or orbicu- 

 lar glands : plants annual. 2. T. IlcUoscopia. 

 Leaf-blades entire : involucre with reniform or crescent- 

 shaped glands: plants annual, biennial, or perennial. 

 Plants annual or biennial : seeds pitted 



Capsules with 2-crested carpels : seeds with 1-4 series 



of pits. 3. T. Peplus. 



Capsules with rounded carpels : seeds pitted all over. 4. T. commutata. 

 Plants perennial : seeds smooth. 



Glands of the involucre oblong : leaf-blades broad. 5. T. Darlingtonii. 

 Glands of the involucre lunate : leaf-blades narrow. 6. T. Cyparissias. 



1. T, Lathyrus (L.) Hill. Stems 2-12 dm. tall: blades of the upper leaves 

 lanceolate to linear-lanceolate, 3.5-12 cm. long: bracts ovate to ovate-lanceo- 

 late: involucres 4-5 mm. long; lobes triangular, toothed at the apex, surpassing 

 the broad crescent-shaped glands: capsules 10-12 mm. broad: seeds oblong- 

 ovoid, 5-6 mm. long, wrinkled. — M. S. Occasional, on roadsides and about 

 gardens. Nat. of Eu. ■ — Mole-plant. Caper-spurge. Myrtle- spurge. 



2. T. Helioscopia (L.) Hill. Stems 1-3.5 dm. tall: leaf -blades spatulate to 

 cuneate, 1.5-4 cm. long, finely toothed near the rounded or emarginate apex: 

 bracts of the rays cuneate to oblong-cuneate: involucres turbinate-campanulate, 

 about 1.5 mm. high, short-peduncled : glands transversely oval, about 0.5 mm. 

 wide, unappendaged : capsules about 4 mm. broad, the lobes rounded: seeds 

 ovoid, nearly 2 mm. long^ finely reticulate. — S. Occasional, in fields. Nat. 

 of Eu. — Wartweed. 



3. T. Peplus (L.) Hill. Stems erect, 1-3 dm. tall: leaf -blades oblong or 

 obovate, 1-4 cm. long: bracts ovate or triangular-ovate: involucres 1-1.5 mm. 

 long; horns less than 1 mm. long: capsules 2.5-3 mm. broad, smooth: seeds 

 oblong or ovoid-oblong, 1.5 mm. long or less, with 1-4 series of pits. — M. 

 Occasional, on roadsides and fields. Nat. of Eu. — Petty-spurge. 



4. T. commutatus (Engelm.) Kl. & Garcke. Stems decumbent, 1-4 dm. long: 

 leaf -blades spatulate to ovate, 1-4 cm. long: bracts reniform or ovate-reniform: 

 involucres 2.5 mm. long; horns 1 mm. long or nearly so: capsules 3.5-4 mm. 

 broad, smooth: seeds ovoid, fully 2 mm. long, or sometimes smaller, irregu- 

 larly pitted. — S. Frequent, in woods, especially near Safe Harbor. — Schists. 



5. T. Darlingtonii (A. Gray) Small. Stems 3-15 dm. tall: leaves few; blades 

 oblanceolate to oblong-lanceolate, 3.5-10 cm. long: bracts broadly ovate to 

 reniform: involucres 3-4 mm. long; lobes ovate or quadrate, toothed or often 

 notched; glands oblong: capsules 8^9 mm. broad, warty: seeds ovoid-globose, 

 3^ mm. long. — S. Rare, in woods and thickets. — Schists. 



6. T. CjTJarissias (L.) Hill. Stems often tufted, 1-3 dm. tall: leaves very 

 numerous; blades linear, 2-4 cm. long, acute or acutish, entire: bracts 

 ovate, deltoid or reniform: involucres campanulate, about 2 mm. long, sessile: 

 glands lunate, nearly 1 mm. wide: capsules 3-Iobed, about 3 mm. wide, granu- 

 lar, the lobes rounded : seeds ovoid, nearly 2 mm. long, smooth. — Frequent, on 

 roadsides and in waste places. Nat. of Eu. — Cypress-spurge. 



7. POrNSETTIA Graham. Annual or perennial herbs, or woody plants. 

 Leaf -blades entirejv toothed, or lobed. Stipules present. Involucres solitary or 

 cymose, each with 1, or rarely 3 or 4, unappendaged glands. Capsule smooth. 

 Seeds tuberculate. 



1. P. dentata (Michx.) Small. Stems 2-4 dm. tall, pubescent: leaf -blades 1-9 

 cm. long, ovate, lanceolate, or nearly linear: involucres 2.5-3 mm. long; glands 

 usually solitary : capsules 4-4.5 mm. broad : seeds prominently tuberculate. — 

 M. Eare, along the Conestoga Creek, Lancaster. Nat. of the West. — Not 

 recently collected. — Sum. 



