202 XXXIII. ANACARDIACE.E. RHUS. 



united, short or ; stigmas 2 ; fruit 2-celled, 2-seeded samaras, with 

 a broad, orbicular margin. Shrubs with 3 5-foliate leaves. Fls. 

 cymose. 



P. TRIFOLIATA. Shrubby Trefoil. 



Lvs. 3-foliate, Ifts. sessile, ovate, short-acuminate, lateral ones inequila- 

 teral, terminal ones cuneate at base ; cymes corymbose ; sta. mostly 4 ; sty. 

 short. An ornamental shrub, 6 8f high, Western States ! rare in Western 

 N. Y. Leaflets 3 4j' by H If, the peduncles rather longer. Flowers white, 

 odorous, nearly J' diam. Samara nearly I' diam. 



3. AILANTHUS. 



9 $ c? Sepals 5, more or less united at base ; petals 5 : $ stamens 

 2 3 ; ovaries 3 5 ; styles lateral : fruit a 1 -celled, 1 -seeded samara 

 with oblong margins; cT stamens 10; 9 ovaries, styles and samarse 

 as in $. Oriental. Trees and shrubs with pinnate leaves. Fls. in 

 panicles. 



A. GLANDULOSA. Desf. Tree of Heaven. Lvs. glabrous, unequally pinnate ; 

 Ifts. ovate or oblong-lanceolate, acuminate, shortly petiolulate, with one or two 

 obtuse, glandular teeth each side at base, terminal one long-petiolate. A tree 

 of large dimensions, and with extremely rich and luxuriant foliage, native of 

 China and Japan. Trunk straight, with a smooth, brown bark. Leaves 3 5f 

 in length, with 10 20 pairs of leaflets and an odd one. Flowers in terminal 

 panicles, greenish, perfecting seed in our climate. The tree is of extremely 

 rapid growth, and is becoming common in our streets and shrubberies, f 



ORDER XXXIII. ANACARDIACEJE. SUMACHS. 



Trees or shrubs, with a resinous, gummy, caustic, or even milky juice. 



Lvs. alternate, simple or ternate or unequally pinnate, without pellucid dots. 



Fls. terminal or axillary, with bracts, commonly dioecious. 



Cal. Sepals 3 5, united at base, persistent. 



Cor. Petals same number as sepals, sometimes 0, imbricate in aestivation. 



Sta. as many as petals, alternate with them, distinct, on the base of the calyx. 



Ova. 1-celled, free. Ovule one. Styles 3 or 0. Stigmas 3. 



Fr. a berry or drupe, usually the latter and 1-seeded. 



Genera 41, species 95, chiefly natives of tropical regions, represented in the United States by the genus 

 Rhus only. 



Properties. These plants abound in a resinous juice, which is often poisonous, but is used as an indeli- 

 ble ink in marking linen, and as an ingredient in varnish. Even the exhalations from some of the species 

 are deemed poisonous. The Cashew nut is the product of a small tree of both Indies. When fresh the 

 kernel is full of a milky juice, and has a most delicious taste, but the coats are filled witk a caustic oil 

 which blisters the skin, and kills warts. 



RHUS. 



Said to be from psat, to flow ; because used in haemorrhage. 



Calyx of 3 sepals united at base ; petals and stamens 5 ; styles 

 3, stigmas capitate ; fruit a small, 1-seeded, subglobose, dry drupe. 

 Small trees or shrubs. Leaves alternate, mostly compound. Flowers 

 often by abortion 9 cT or 9 cf . 



* Leaves pinnate. 



1. R. GLABRA. Smooth Sumach. 



Lvs. and branches glabrous; Ifts. 615 pairs, lanceolate, acuminate, 

 acutely serrate, whitish beneath ; fr. red, with crimson hairs. Thickets and 

 waste grounds, U. S. and Can. Shrub 6 15f high, consisting of many strag- 

 gling branches, smooth, except its fruit. Leaflets about 3' long, j as wide, 

 sessile except sometimes the terminal odd one. Flowers in terminal, thyrsoid, 

 dense panicles, greenish-red, 9 (? Fertile ovaries clothed with grayish down, 

 which in the fruit becomes crimson, and contains malic acid (bi-malate of 

 lime, Prof. Rogers), extremely sour to the taste. Jn. Jl. The bark of this 

 and other species may be used in tanning. The drupes dye -red. Lands long 

 neglected are sometimes overrun by this shrub. 



