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 pulpy. 



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

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

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

 flowers pale yellow, about 5 cm. broad, with 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. RafinSsquii Engelm. Prostrate, deep green ; joints broadly obovate' or 

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

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

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

 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. O. and Mich, to Minn., and s. to Ky. and Tex. 



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

 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, flat 

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

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

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

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

 variable. 



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

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

 bristles few, larger spines 1-4, cruciate, with 4-6 smaller white radiating ones 

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



THYMELAEACEAE (MEZEREUM FAMILY) 



Shrubs, with acrid and very tough (not aromatic) bark, entire leaves, and 

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

 as many stamens as its lobes, free from the l-celled 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. DtRCA 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.) 



