EUPHORBIACEAE 699 



2. Ditaxis humilis (Engelm. & Gray) Pax. Perennial. Stem slender, much 

 branched, pubescent, the branches spreading;:, 1-3 dm. long : leaf-blades ovate, oblong or 

 oblanceolate, 1-3 cm. long, entire, narrowed into short petioles : flowers in axillary clus- 

 ters, the staminate with petals a little longer than the 5 sepals and longer than the lobes of 

 the disk : pistillate flowers with 5 sepals and three usually twice 2-cleft styles : capsules short- 

 pedicelled, much depressed, 4-6 mm. in diameter, 3-4-lobed : seeds oval-globose, about 2 

 mm. long, rauricate. 



On prairies, Kansas to Louisiana and Texas. Spring to fall. 



3. Ditaxis Blodg6ttil (Torr. ) Pax. Annual or biennial, sparsely pubescent. Stems 

 usually branched at the base, the branches erect, ascending or decumbent, 1-6 dm. long, 

 often slightly zigzag : leaf-blades oval, elliptic or oblong, or spatulate at base of stem, 1.5- 

 4 cm. long, acute or acuminate, serrate, somewhat acuminate at the base, short-petioled : 

 staminate flowers 3-5 in a cluster : pistillate flowers usually solitary ; calyx strigillose ; 

 sepals linear-lanceolate, acute, 3-5 mm. long ; petals greenish white, oblong, slightly 

 longer than the sepals, or shorter and more acute in pistillate flowers : capsules 3-lobed, 4-5 

 mm. broad, strigose : seeds nearly 2 mm. long, reticulated. 



In sandy soil, Key West, Florida. Spring to fall. 



4. Ditaxis pilosissiina (Benth. ) Heller. Perennial, densely pubescent with woolly 

 hairs. Stems erect or ascending : leaf-blades elliptic, elliptic-ovate or oblong-spatulate at 

 base of stem, 2-5 m. long, obtuse or acutish, several-nerved, sessile : racemes surpassing the 

 leaves, few-flowered : pedicels 3-10 mm. long: calyx pubescent : sepals narrowly lanceolate or 

 linear-lanceolate, becoming 5-7 mm. long, acuminate : petals narrowly spatulate orcuneate, 

 about as long as the sepals, acute, rudimentary in the pistillate flowers : glands villous- 

 hirsute : capsules 3-lobed, about 1 cm. broad, densely hairy : seeds subglobose, 4-5 mm. in 

 diameter, reticulated with sharp ridges. 



On prairies, Texas. Spring to fall. 



5. Ditaxis mercurialina (Nutt. ) Coulter. Perennial. Stem slender, strict, usually 

 simple, channeled, silky, 1-6 dm. high. Leaf-blades ovate to narrowly lanceolate or ob- 

 lanceolate near the base of the stem, 2-5 cm. long, undulate, sessile, often strongly 3-nerved, 

 glabrate : flowers in terminal and axillary racemes ; the staminate with lanceolate or linear- 

 lanceolate, acute, ciliate sepals, and spatulate-oblong, undulate petals : pistillate flowers 

 with 5 spreading lanceolate sepals, 3 times as long as those of the staminate : petals want- 

 ing : capsules depressed, 6-9 mm. in diameter, somewhat silky, 3-lobed : seeds globose- 

 ovoid, 4 mm. long, pointed, wrinkled, indistinctly 2-crested. 



In dry soil, Kansas and Arkansas to Texas. Spring to fall. 



8. MERCURIALIS L. 



Annual or perennial herbs or shrubby plants, with firm or succulent tissues. Leaves 

 opposite : blades entire or often toothed. Flowers mostly dioecious, apetalous. Staminate 

 flowers in more or less elongated spikes or racemes. Calyx membranous, of 3 valvate 

 sepals. Stamens 8-20 : filaments distinct : anthers opening lengthwise. Pistillate flowers 

 with a calyx of 3 sepals. Ovary 2-celled : styles 2, distinct or nearly so : stigmas entire. 

 Ovules solitary in each cavity. Capsule usually 2-lobed. Seed solitary in each cavity, with 

 a smooth or tuberculate crustaceous testa. 



1. Mercurialis dnnua L. Annual, glabrous. Stems 2-6 dm. tall, more or less 



widely branched : leaf-blades thinnish, ovate to lanceolate, acute or slightly acuminate, 



serrate with rounded teeth, or crenate : petioles 5-15 mm. long : staminate flowers in 



interrupted spikes which surpass the leaves : pistillate flowers clustered in the axils : 



capsules 2-lobed, 4-5 mm. broad, hispid : seeds subglobose, 1.5 mm. in diameter, pitted. 



In waste places. South Carolina to Florida and Texas and in other parts of North America. Native 

 of Europe and Africa. 



9. RICINELLA Muell. Arg. 



Dioecious shrubs, with glabrous or rarely tomentose foliage, the branchlets sometimes 

 spine-tipped. Leaves alternate, often clustered at the nodes: blades membranous or parch- 

 ment-like, entire. Flowers apetalous : staminate nearly sessile in axillary clusters. Stamens 

 8-15 : filaments short, distinct : anthers versatile. Pistillate flowers solitary, long-pedi- 

 celled. Ovary 3-celled : styles 3, distinct, lacerate. Ovules solitary in each cavity. 

 Capsule 3-lobed, crustaceous. Seed solitary in each cavity, with a smooth testa. 



1. Ricinella Vaseyi (Coulter) Coult. & Fish. A shrub branching from the base, the 

 branches 1.5-2 m. tall, puberulent, or glabrous in age. Leaves rather few, clustered on the 



