132 ELEMENTS OF BOTANY. 



petals 3-5 or none ; petals hypogynous or perigynous when 

 present ; stamens as many or twice as many as the sepals, 

 inserted on the glandular disk; pistils 2-5, often partially 

 united ; fruit a capsule or a samara. 



I. XANTHOXYLUM. 



Trees or shrubs ; bark, twigs, and petioles usually prickly ; 

 leaves odd-pinnate, punctate with pellucid dots ; flowers in 

 axillary or terminal cymes, monoecious or dioecious ; sepals 

 and petals 3-5 or none ; stamens 3-5, hyj^ogynous ; pistils 

 2-5, distinct, sessile or stipitate ; carpels 2-valved, 1-2-seeded ; 

 seeds smooth and shining. 



1. X. Pterota HBK. Bastard Tronwood. A shrub or small 

 tree ; branches crooked and armed with curved, stipular prickles or 

 sometimes smooth; leaflets 7-11, sessile, obovate, somewhat crenate, 

 dots few, rachis and petiole winged ; flowers in axillary, sessile or 

 short-peduncled clusters; sepals, petals, and stamens 4; ovaries 2; 

 carpels globose, dotted, stipitate. May-June. On rich soil, more 

 common southward. 



2. X. Cjlava-Herculis L. Hercules's Club. A tree 20-40 

 ft. high ; bark very prickly ; prickles on the older j^arts often sur- 

 rounded by a ring of cork; leaflets 9-21, ovate-lanceolate, acuminate, 

 crenate, inequilateral, shining above; cymes terminal, appearing 

 before the leaves ; flowers small, greenish ; sepals and petals 4-5 ; 

 capsules 2-3, sessile. May -June. In rich, moist woods. 



II. PTELEA. 



Shrubs with smooth and bitter bark ; leaves trifoliate ; 

 flowers in terminal cymes, polygamous ; sepals 3-6, decidu- 

 ous, much shorter than the petals ; stamens 4-5, longer than 

 the petals and alternate with them ; pistillate flowers pro- 

 ducing abortive stamens ; ovary compressed, 2-celled ; fruit a 

 2-celled, 2-seeded. broadly winged samara. 



P. trifoliata L. Hop-tree. A shrub 4-8 ft. high; leaves 

 long-petioled, leaflets oval or ovate, acute, obscurely serrate, the lateral 

 ones oblique ; cymes compound ; flowers greenish ; stamens mostly 4, 

 filaments villous; samara about 1 in, in diameter, wing emarginate, 

 strongly reticulated. May-June. Rocky banks. 



