Cneoridium. RUTACE^E. 97 



1. PTELEA, Linn. HOP-TREE. 



Flowers polygamous. Sepals, petals, and stamens 4 or 5. Ovary with a short 

 thick stipe, 2-celled ; cells 2-ovuled, the lower ovule abortive : style short. Fruit a 

 broadly winged orbicular samara, 2-celled and 2-seeded ; the wing embracing a slen- 

 der stipe. Seeds oblong. Embryo straight, with ovate-oblong cotyledons. 

 Shrubs or small trees ; leaves mostly trifoliolate, with sessile leaflets ; flowers small, 

 greenish-white, in terminal cymes or compound corymbs. 



A genus of half a dozen species, confined to the United States and Mexico. 



1. P. angustifolia, Benth. A shrub 5 to 25 feet high, with chestnut-colored 

 punctate bark : leaflets oblong-lanceolate, somewhat rhomboidal, 1 to 2^ inches 

 long, usually acute or acuminate, entire, sparingly pubescent, becoming smooth and 

 shining with age : flowers numerous, in compound corymbs, pubescent : sepals 

 small : petals 2 or 3 lines long, spreading : fruit 6 to 8 lines broad, emargiuate at 

 base and often above ; stipe narrow, 1 to 2 lines long. PI. Hartw. 9 ; Gray, PI. 

 Fendl. 28. 



Frequent about Clear Lake and on Mt. Diablo, extending to Texas and Mexico. It differs 

 from P. trifoliuta of the Atlantic States in its narrower and smaller leaves, larger flowers, more 

 narrowly winged fruit emarginate at base, and shorter narrower stipe. Its odor is sometimes 

 agreeable (like that of Lindera Benzoin), sometimes unpleasantly rank, most fragrant when the 

 wood is broken or crushed. 



2. THAMNOSMA, Torr. 



Sepals 4. Petals 4, erect. Stamens 8, at the base of a cup-shaped crenate or 

 lobed disk. Ovary stipitate, 2-lobed and 2-celled, with 5 or 6 ovules in each cell : 

 style elongated. Capsule didymous, coriaceous, dehiscent down the inner edge of 

 each lobe. Seeds 4 to 6 in each cell, reniform. Embryo curved, terete. Low 

 glandular desert shrubs, strongly scented ; leaves simple and linear, alternate ; 

 flowers purple or yellow, solitary. The following are the only species. 



1. T. montanum, Torr. A smooth diffusely and stiffly branched shrub, some- 

 what spinose, a foot or two high, with yellowish -green bark : leaves scattered, 4 to 

 12 lines long, soon deciduous : peduncles axillary, 1 to 4 lines long, with several 

 small bracts : calyx short : petals 4 or 5 lines long, nearly closed, apparently 

 purple : capsule yellow, of two subglobose nearly distinct cells, three lines long ; 

 stipe about a line long. Frem. Rep. 313 ; Pacif. R. Rep. iv. 73, t. 3. 



On the southern borders of the State, from San Felipe to Fort Mohave, and eastward to S. 

 Utah ; rather rare. 



T. TEXANUM, Torr. (Rutosma Texanum, Gray, Gen. 111. ii. 144, t. 155.) "Woody only at 

 base, the slender stems 3 to 15 inches high : flowers much smaller, on short naked pedicels, yel- 

 low tinged with purple : capsule very shortly stipitate, lobed nearly to the middle, rather smaller. 

 Frequent from Texas to Arizona and Sonora ; perhaps reaching S. E. California. 



3. CNEORIDIUM, Hook. f. 



Sepals, petals, and stamens 4, or stamens sometimes 8, the alternate ones much 

 shorter. Disk annular, obtusely 8-angled. Ovary globose, sessile, of a single car- 

 pel, 1-celled, 2-ovuled : style lateral, curved, short. Fruit " drupaceous," 1-2- 

 seedetl. Seed globose, with fleshy albumen : embryo curved. A low smooth 

 shrub ; leaves opposite, linear-spatulate, entire ; flowers small, axillary and solitary 

 or somewhat corymbose, on short bracted peduncles. A single species. 



. 1. C. dumosum, Hook. f. Heavy-scented, much-branched, 2 to 4 feet high, 

 leafy : leaves often fascicled, | to 1 inches long, narrow : flowers white, 2 to 3 



