354 RUTACEAE. [Vol.. II. 



2. PTELEA L. Sp. PI. 118. 1753. 



Shrubs or small trees, without prickles, the bark bitter. Leaves 3-5-foliolate, with entire 

 or serrulate leaflets. Flowers greenish white, polygamous, corymbose-paniculate. Calyx 

 4-5-parted, the lobes imbricated. Petals 4 or 5, much longer than the calyx, also imbricated. 

 Stamens 4 or 5, alternate with the petals; filaments hairy on the inner side, present in the 

 pistillate flowers but the anthers abortive or wanting. Ovary flattened, 2-celled (rarely 

 3-celled). Fruit a nearly orbicular samara, 2-winged (rarely 3-winged), indehiscent. Cells 

 i-seeded. Seed oblong-ovoid. [Greek, Elm.] 



About 6 species, natives of the United States and Mexico. 



i. Ptelea trifoliata L. Three-leaved Hop-tree. Shrubby Trefoil. 



(Fig. 2271.) 



Ptelfa trifoliata I,. Sp. PI. 118. 1753. 



A shrub or small tree, with a maximum 

 height of about 20 and trunk diameter 

 of 6'. Leaves long-petioled, 3-foliolate, 

 pubescent when young, glabrate when 

 old; leaflets ovate or oval, 2'- f long, ses- 

 sile, crenulate, acute or obtuse, the lateral 

 ones somewhat oblique, the terminal one 

 more or less cuneate at the base; flowers 

 about 5" broad, in terminal compound 

 cymes; odor disagreeable; sepals y^" long, 

 obtuse; petals about 3" long, oblong; 

 samara 8 // ~9 // in diameter, the wing 

 membranous and reticulated, emarginate, 

 tipped with the minute persistent style or 

 this finally deciduous. 



In woods, Long Island to Florida, west to 

 southern ( Mitario, Minnesota, Texas and 

 northern Mexico. The fruit is bitter and has 

 been used as a substitute for hops. The 

 foliage has an unpleasant odor. Wood light 

 brown; weight per cubic foot 43 Ibs. Called 

 also Wafer-ash, Swamp-Dogwood, Wingseed. 

 June. 



Family 55. SIMARUBACEAE DC. Bull. Soc. Philom. 2: 209. 1811. 



AILANTHUS FAMILY. 



Trees or shrubs, with bitter bark, and mainly alternate and pinnate not 

 punctate leaves. Stipules minute or none. Inflorescence axillary, paniculate 

 or racemose. Flowers regular, dioecious or polygamous. Calyx 3~5-lobed or 

 divided. Petals 3-5. Disk annular or elongated, entire or lobed. Stamens of 

 the same number as the petals, or twice as many; anthers 2-celled. Ovaries 

 2-5, or single and 2-5-lobed, i-5-celled; styles 1-5. Seeds generally solitary 

 in the cells; embryo straight or curved. 



About 27 genera and 145 species, natives of warm or tropical regions, distinguished from RU- 

 TACEAE mainly by their non-punctate foliage. 



i. AILANTHUS Desf. Mem. Acad. Paris, 1786: 265. pi. 8. 1789. 



Large trees, with odd-pinnate leaves, and terminal panicles of greenish-white polyga- 

 mous flowers. Calyx short, 5-cleft, the lobes imbricated. Petals 5, spreading, valvate. 

 Disk lo-lobed. Staminate flowers with 10 stamens inserted at the base of the disk. Pistil- 

 late flowers with a deeply 2-5-cleft ovary, its lobes flat, cuneate, i-celled, and 2-3 stamens. 

 Ovules solitary in each cavity. Samaras 2-5, linear, or oblong, membranous, veiny, i-seeded 

 at the middle. Seed compressed; cotyledons flat, nearly orbicular. [From the Chinese 

 name.] 



Three species, natives of China and the East Indies. The following has become widely natu- 

 ralized in eastern North America. 



