Zanthoxyltjm. XANTHOXYLACE.E. . 133 



Torr. 4. Gr. ft. N. Am. 1. p. 214. Z. fraxineum, Willd. Berol. haum. (1796), and $p. 4. 

 p. 757 ; Pursh, fl. 1. p. 210; DC. prodr. 1. p. 726 ; Bigel. med. hot. t. 59, and fl. Bost. 

 p. 376 ; Hook. fi. Bor.-Am. I. p. 118. Z. tricarpum, Hook. I. c. not of Michx. Z. rami- 

 florum, Michx. fl. 2. p. 235. Z. Clava-Herculis, var. Linn. Z. mite, Willd- enum. p. 1013; 

 DC. I. c. 



A shrub 4-6 feet high ; the stronger prickles mostly in pairs at the base of the young 

 branches. Leaves 4-5 pairs, ■with an odd one ; common petiole often with a few short 

 prickles : leaflets 1-2 inches long, downy when young, but at length only slightly pubescent 

 beneath. Flowers expanding before the leaves, greenish. Barren and perfect flowers growing 

 on the same plant. Sepals oblong, obtuse. Stamens much longer than the sepals. Ovaries 

 3 - 4 in the perfect flowers, mostly 5 in the pistillate ones, raised on a short stalk, ovoid- . 

 globose. Styles as long as the ovaries, scarcely connate, a little twisted. Capsules about 

 the size of a peppercorn, greenish or with a red tinge, marked with impressed dots, half 2- 

 valved. Seed solitary, suspended from near the summit of the cell. 



Banks of rivers and lakes, and in rocky woods ; northern and western parts of the State ; 

 not found below the Highlands. Fl April and May. Fr. June. The bark is pungent, and 

 is employed as a stimulant and diaphoretic in rheumatism. lis virtues are owing to a peculiar 

 active principle, called Zanthoxylin, or Xanthopicrite. See Bigeloio's Med. Bot. I. c, and 

 Wood 4- Bache's U. S. Disp. p. 697. 



2. PTELEA. Linn. ; Endl. gen 5977. shrubby TREFOIL. 



[ The Greek name of the Elm, derived from ptao, to fly ; in allusion to the winged seed-vessels.] 



Polygamo-dioecious. Sepals 3-6 (usually 4), small. Petals much longer than the sepals, 

 spreading. Stamens (commonly 4) alternate with and longer than the petals : filaments 

 subulate, thickened below, and hairy on the inside ; in the fertile flowers, very short, and 

 with sterile anthers. Ovary of 2 united carpels, placed on a convex torus : ovules 2 in 

 each carpel, situated one above the other : style short or united, or none : stigmas 2. Fruit 

 a samara, 2-celled, the margin expanded into a broad orbicular membranaceous and reticu- 

 lated wing. Seeds oblong-ovoid, one in each cell. — Shrubs with pinnately 3 - 5-foliolate 

 leaves, which are furnished with pellucid dots. Lateral leaflets inequilateral. Flowers 

 whitish-green, in corymbose or paniculate cymes. 



1. Ptelea trifoliata, Linn. Swamp Dogwood. Slinking Ash. 



Leaflets sessile, ovate, mostly acuminate, the terminal one cuneiform and attenuate at the 

 base ; flowers commonly with 4 stamens ; style short. — Walt. fl. Car. p. 88 ; " Schmidt, 

 arb. 2. t. 76;" Michx. fl. 1. p.99; Ell. sk. 1. p. 211 ; Torr. fl.l.p.l89; DC. prodr. 2. 

 p. 82; Torr. ^ Gr. fi. N. Am. \.p. 215. 



