234 NORTH AMERICAN FLORA [Volume 25 



mm. long, pubescent ; petals elliptic or somewhat broadened upward, those of the staminate 

 flowers 2.5-3 mm. long, those of the pistillate flowers not seen; drupes globose, 11-13 mm. 

 in diameter, bluish. 



Type locality : Signal Hill, St. Thomas. 



Distribution : Lesser Antilles. 



Illustration : E. & P. Nat. Pfl. 3' : /. 129, A-G. 



8. PICRELLA * Baillon, Adansonia 10 : 150. 1871. 



Shrubs with slender branches. Leaves opposite, relatively small ; blades 3-foliolate. 

 petioled, the leaflets palmate, the blades broad, flat, entire. Flowers perfect, in small axil- 

 lary panicles, short-pedicelied. Sepals 4, spreading, short and broad. Petals 4, erect, 

 except the recurved tips, somewhat swollen at the base, much longer than the calyx, 

 Stamens 4, borne at the base of the annular-lobed disk ; filaments elongate, but rather 

 thick ; anthers short. Ovary 4-lobed, the carpel-bodies nearly distinct. Styles united, 

 short and stout. Stigma capitate, slightly elongate. Fruit not seen. 



Type species, Picrella trifoliate. Baillon. 



1. Picrella trifoliata Baillon, Adansonia 10: 150. 1871. 

 A shrub with slender glabrous twigs. Leaves opposite, mostly 4-8 cm. long, the 

 petioles slender, nearly as long as the leaflets or longer, the leaflets thin, ovate, oval or 

 obovate, mostly 1-2.5 cm. long, obtuse or notched at the apex, entire, more or less con- 

 tracted at the base ; panicles short-peduncled, shorter than the leaves ; sepals 4, deltoid 

 to ovate-deltoid, about 1.5 mm. long; petals 4, ovate to oblong-ovate, 3-4 mm. long, re- 

 curved at the tip, acutish; stamens shorter than the petals. 



Type locality : Found in cultivation in Paris, and supposed to be of Mexican origin. 

 Distribution : Known only from the original specimen. 

 Illustration: AdansonialO : pi. 10. 



9. AILANTHUS t Desf. Mem. Acad. Paris 1786 : 265. 1789. 



Trees with pale bark and spreading branches. Leaves alternate, numerous ; blades un- 

 equally pinnate. Flowers polygamo-dioecious, in large terminal panicled racemes. Sepals 

 5 or 6, nearly equal, rather broad, imbricate. Petals 5 or 6, rather broad, valvate, spreading. 

 Disk flat, 10-lobed. Staminate flowers with 10 stamens inserted at the base of the disk ; 

 filaments filiform ; anthers short : perfect flowers with stamens 2-3, and the pistillate flowers 

 with none. Ovary 2-5-lobed, the lobes prominent, flattened ; styles united ; stigmas spread- 

 ing ; ovules solitary in each cavity. Samaras elongate, solitary, or 2-5 together, distinct, the 

 wings membranaceous, veiny, 1-seeded at the middle. Seed compressed. 



Type species, Ailanthus glandulosa Desf. 



1. Ailanthus glandulosa Desf. Mem. Acad. Paris 1786 : 265. 1789. 

 A large tree with smoothish gray bark and a stout trunk. Leaves deciduous, 3-9 dm. 

 long ; leaflets 11-41, opposite or alternate, the blades oblong-lanceolate to lanceolate or ovate, 

 7-18 cm. long, acute or acuminate at the apex, entire or with 2-4 coarse teeth at the base, 

 cordate or truncate and often oblique at the base, petioluled ; panicles 1-3.5 dm. long ; sepals 

 ovate to triangular-ovate, 1-1.5 mm. long, acute, ciliolate ; petals ovate or oval, 2.5-4 mm. 

 long, greenish or yellowish, villose near the base within ; stamens villose at the base ; samaras 

 oblong to oblong-elliptic, 3-5 cm. long, spirally twisted. 



Type locality : 



Distribution : Southern Ontario to Massachusetts, North Carolina, Alabama, and Texas. 

 Native of China. 



Illustrations : Mem. Acad. Paris 1786 : pi. 8; Millsp. Am. Med. PI. pi. 35 ; Britt. & Brown, 

 111. Fl. f. 2272 ; Britton, N. Am. Trees/. 541, 542 ; Hough, Handb. Trees/. 352-354 ; Keeler, Native 

 Trees, opp. 36, 39, and 40. 



* Generic and specific descriptions compiled from the original descriptions and the 

 accompanying plate. 



t Sometimes spelled Ailantus. 



