EUPHORBIACEAE 707 



nate with a calyx of 5 partially united sepals. Stamens 10, in 2 series : filaments slender, 



those of the inner series attached to the lobes of the disk : anthers opening lengthwise. 



Pistillate flowers with a calyx similar to that of the staminate but the tube often shorter. 



Ovary 3-celled : styles 3, slightly united at the base. Ovules solitary in each cavity. 



Capsule 3-celled. Seeds solitary in each cavity. 



Leaf-segments lobed. 1. M. Carthaginensis. 



Leaf-segments entire. 2. if. Manihot. 



1. Manihot Carthagin^nsis (Jacq. ) Muell. Arg. Stems 4-10 dm. tall, often spar- 

 ingly branched : leaf-blades orbicular or reniform in outline, 3-o-lobed, 8-12 cm. broad, 

 the lobes ovate, fiddle-shaped, pinnatifid or the lower ones undulate, acute or acuminate ; 

 petioles about as long as the blades or shorter : racemes few-flowered : calyx of the stami- 

 nate flowers salverform, the lobes linear or linear-lanceolate : pistillate flowers below the 

 staminate ; tube none or very short ; lobes linear or linear-lanceolate : bracts surpassing 

 the pedicels. 



In sandy soil, southern Texas to Mexico and tropical America. 



2. Manihot Manihot ( L. ) Cockerell. Stems 1-1.5 m. tall, more or less branched : leaf- 

 blades 3-7-parted, the segments linear to elliptic, or slightly broadest above the middle, 

 acute or acuminate, entire ; petioles about as long as the blades or longer : panicles spread- 

 ing, often glaucous : bracts shorter than the pedicels : calyx campanulate, 7-8 mm. high ; 

 lobes ovate, obtuse, about as long as the tube ; calyx of the pistillate flowers with a shorter 

 tube than that of the staminate. [31. vliiissima Pohl.] 



In sandy soil, Keys of Florida and tropical America. 



23. CHAMAESYCE S. F. Gray. 

 Annual or perennial herbs or shrubs. Stems often radially branched at the base, the 

 branches ascending or prostrate, sometimes creeping, forking. Leaves opposite : blades 

 entire or toothed, more or less oblique at the base : stipules delicate, entire or fringed. In- 

 volucres solitary in the axils or in axillary cymes : glands 4, sessile or stalked, naked or 

 usually with an appendage, one sinus of each involucre glandless. Capsule smooth, some- 

 times pubescent, the angles sharp or rounded. Seeds angled, with minute caruncles, white 

 or black, the faces smooth or transversely wrinkled. Spurge. 



A. Leaf-blades entire. 



Plants with relatively prostrate stems or branches. 

 Annuals or biennials. 



Seeds over 1.5 mm. long. 



Leaf-blades fully thrice as long as broad, acute or apiculate : capsules 



3—1 mm. long. 

 Leaf-blades twice as long as broad, obtuse or retuse : capsules 2.r> mm 

 long. 

 Seeds less than 1.5 mm. long. 



Leaf-blades fully twice as long as broad, or most of them manifestlj 

 longer than broad. 

 Seeds barely 1.5 mm. long : species campestrian. 

 Seeds about 1 mm. long : species Floridian. 



Leaf-blades mostly with parallel sides : seeds ovoid, smooth. 

 Ultimate divisions of the inflorescence open cymes. 

 Ultimate divisions of the inflorescence raceme-like clusters. 

 Leaf-blades never with parallel sides : seeds oblong, transversely 

 wrinkled. 

 Leaf-blades as broad as long or nearly so. 

 Foliage and capsules glabrous. 



Stipules toothed : appendages of the glands minute or obsolete. 

 Stipules parted : appendages of the glands petal-like. 

 Foliage and capsules manifestly pubescent. 

 Stems or branches hirsute or villous-hirsute. 



Leaf-blades hirsute, not cordate at the base : involucre pedun- 



cled ; glands red : seeds nearly smooth. 

 Leaf-blades lanate, cordate at the base : involucre sessile ; 

 glands greenish brown : seeds transversely wrinkled. 

 Stems or branches finely canescent. 



Leaf-blades apiculate : capsules pubescent all over. 

 Leaf-blades obtuse : capsules pubescent along the angles. 

 Perennials. 



Involucres inconspicuous, less than 1 mm. high ; appendages obsolete. 

 Involucres corolla-like, over 1 mm. high ; appendages petal-like. 

 Plants with relatively rigid, erect or ascending stems or branches. 

 a. Perennials. 



.Foliage glabrous. 15. C. Fendleri. 



Foliage pubescent. 



* Stems simple at the base : glands with obsolete appendages : capsules 



less than 1 mm. high. 16. C. adicioides. 



