THYMELAEACEAE (MEZEREUM FAMILY) 589 



2. OPUNTIA [Tourn.] Mill. Prickly Pear. Indian Fig 



Sepals and petals not united into a prolonged tube, spreading, regular, the 

 inner roundish. — Stem composed of joints (flattened in ours), bearing very 

 small awl-shaped and usually deciduous leaves arranged in a spiral order, with 

 clusters of barbed bristles and often spines in their axils. Flowers in our spe- 

 cies yellow, opening in sunshine for more than one day. (A name of Theo- 

 phrastus, originally belonging to some different plant.) 



* Spines small or none; fruit x>ulpy. 



1. 0. vulgaris Mill. Prostrate or spreading, Wjht green; joints broadly ob- 

 ovate, 5-10 cm. long; leaves minute (4-5 mm. long), ovate-subulate, generally 

 appressed; bristles short, greenish-yellow; spines solitary or more often none; 

 Jtovers pale yellow, about 5 cm. broad, icith about 8 petals ; fruit 2.5 cm. long. 

 — Sandy fields and dry rocks, Nantucket to S. C, near the coast ; Falls of the 

 Potomac. 



2. 0. Rafin^squii Engelm. Prostrate, deep green ; joints broadly obovate oi 

 orbicular, 7-12 cm. long ; leaves 6-8 myn. long, spreading; bristles bright red- 

 brown, with a few small spines and a single strong one (1.8-2.4 cm. long) oi 

 none; flowers yellow, 6-9 cm. broad, sometimes with a reddish center ; petah 

 10-12 ; fruit 3.6 cm. long, with an attenuated base. (Probably O. cespitosa. 

 mesacantha, and humifusa Raf., in part.) — Sandy soil, limestone bluffs, etc., 

 n. (). and Mich, to Minn., and s. to Ky. and Tex. 



Var. minor Engelm. Dwarf^; joints orbicular, 5 cm. in diameter, nearlj 

 spineless. — Sandstone rock, s. Mo. (Engelmann according to Coulter.) 



* * Very spiny ; fruit dry and prickly. 



3. 0. polyacantha Haw, Prostrate, joints light green, broadly obovate, flai 

 and tubercidate, 5-15 cm. long; leaves small (3-4 mm. long), their axils armed 

 vnth a tuft of straw-colored bristles and 5-10 slender radiating spines (2.5-5 cm. 

 long) ; flowers light yellow, 5-7.5 cm. broad ; fruit with spines of variable length 

 ( O. missouriensis DC. ) — Wise. to. Mo. , and westw. across the plains ; verj 

 variable. 



4. 0. fragilis (Nutt.) Haw. Subdecumbent ; joints small (2.5-5 cm. long oi 

 le.ss), ovate, compressed or tumid, or even terete ; leaves hardly 2 mm. long, red ; 

 bristles feiG, larger spines 1-4, cruciate, vnth 4-6 smaller white radiating one>- 

 below ; flowers yellow. — Minn., la., Kan., and westw. 



THYMELAEACEAE (Mezereum Family) 



Shrubs, xoith acrid and venj tough {not aromatic) bark, entire leaves, and 

 perfect flowers with a regidar and simple colored calyx, bearing usually twice 

 as many stamens as its lobes, free from the 1-cellecl and 1-ovuled ovary, which 

 forms a berry-like drupe in fruit, with a single suspended anatropous seed. 

 Embryo large ; albumen little or none. 



1. Dirca. Calyx tubular, without spreading lobes. Stamens (8) and style exserted. 



2. Daphne. Calyx-lobes (4) spreading. Stamens (8) included. Style short or none. 



1. DIRCA L. Leatherwood. Moosewood 



Calyx petal-like, tubular-funnel-shaped, truncate, the border wavy or ob- 

 scurely about 4-toothed. Stamens inserted on the calyx above the middle, the 

 alternate ones longer. Style thread-form. Drupe ovoid, reddish. — A much 

 branched bush, with jointed branchlets, oval-obovate alternate leaves on very 

 short petioles, the bases of which conceal the buds of the next season. Flowers 

 light yellow, preceding the leaves, 3 or 4 in a cluster from a bud of as many 

 dark-hairy scales, these forming an involucre, from which soon after proceeds 

 a leafy branch. (Name of uncertain derivation.) 



