RUTACE^E. (RUE FAMILY.) 45 



1. E. cicutarium, L'Her. Hairy, much branched from the base : leaf- 

 lets laciniately pinnatitid with narrow acute lobes: peduncles exceeding the 

 leaves : petals bright rose-color : pedicels at length rerlexed, the fruit still 

 erect. — E. Utah and throughout the whole region west of the Rocky Moun- 

 tains. Known as " Alfilaria," " Pin-clover," and " Pin-grass." 



3. OXALIS, L. Wood-Sorrel. 



Low, often acaulescent, with obcordate leaflets and peduncles umbellately 

 or cymosely few to many-flowered. 



1. O. violacea, L. Acaulescent, nearly smooth, leaves and scapes from a 

 scaly bulb: scapes longer than the leaves, umbellately flowered : petals violet: 

 capsule few-seeded. — Colorado, and common eastward. 



2. O. CorniClllata, L. Caulescent, more or less villous, from running root- 

 stocks : stems sometimes 2 or 3 feet high: petals yellow: capsule many-seeded. 



Var. stricta, Sav. Without stipules. — 0. stricta, L. Colorado and east- 

 ward across the continent. 



Order 19. RUTACEiE. (Rue Family.) 



Shrubs or small trees, with pellucid or glandular-dotted aromatic 

 leaves, definite hypogynous stamens, and few seeds. — Sepals and petals 

 4 or 5, imbricated in the bud. Stamens as many or twice as many as the 

 petals, inserted outside of a hypogynous disk. Stipules noue. 



1. Ptelea. Leaves 3-foliolate. Fruit orbicular, indehiscent, broadly winged. Stamens 4 



or 5. 



2. Thamnosma. Leaves simple, alternate. Fruit a 2-lobed coriaceous capsule. Sta- 



mens S. 



1. PTELEA, L. Shrubby Trefoil. Hop-tree. 



Flowers polygamous. Ovary with a short thick stipe. 2-celled ; cells 2-ovuled, 

 the lower ovule abortive : style short. — Shrubs or small trees; flowers small, 

 greenish-white, in terminal cymes or compound corymbs. 



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

 colored punctate bark : leaflets oblong-lanceolate, entire, becoming smooth 

 and shining with age : fruit emarginate at base and often above ; the stipe 

 narrow. — S. Colorado to California and Texas. 



2. THAMNOSMA, Torr. 



Disk cup-shaped, crenate or lobed. Ovary stipitate, 2-celled ; cells 5 oi 

 6-ovuled: style elongated. — Low glandular desert shrubs, strongly scented ; 

 leaves linear ; flowers solitary. 



1. T. Texana, Torr. Woody only at base, the slender stems 3 to 15 

 inches high : flowers on short naked pedicels : petals yellow tinged with 

 purple. — Rutosma Texanum, Gray. S. W. Colorado and southward. 



