326 TREES OF NORTH AMERICA 



XVI. ANONACE-2EJ. 



Trees or shrubs, with watery juice, slender terete branchlets marked by 

 conspicuous leaf-scars, and fleshy roots. Leaves alternate, conduplicate in the 

 bud, entire, feather-veined, petiolate, without stipules. Flowers perfect, soli- 

 tary, axillary or opposite the leaves ; sepals 3, valvate in the bud ; petals 6, 

 in 2 series, imbricated or valvate in the bud ; stamens numerous, inserted on 

 the subglobose or hemispherical receptacle, with distinct filaments shorter than 

 their fleshy connectives terminating in a broad truncate glandular appendage ; 

 anthers introrse, 2-celled, opening longitudinally ; pistils inserted on the sum- 

 mit of the receptacle ; ovary 1-celled ; ovules 1 or many, anatropous. Fruit 

 baccate or compound. Seeds inclosed in an aril ; seed-coat thin, crustaceous, 

 smooth, brown, and lustrous; albumen ruminate, deeply penetrated by the 

 folds of the inner layer of the seed-coat ; embryo minute ; radicle next the 

 hilum. Two of the forty-eight or fifty genera of the Custard-apple family, 

 confined almost exclusively to the tropics and more numerous in the Old 

 World than in the New, occur in North America. 



CONSPECTUS OF THE NORTH AMERICAN GENERA. 



Petals imbricated in the bud ; ovules numerous; fruit developed from one pistil. 



1. Asimina. 



Petals valvate in the bud ; ovule solitary ; fruit developed from several confluent pistils. 



. 2. Anona. 

 1. ASIMINA, Adans. 



Trees or shrubs, emitting a heavy disagreeable odor when bruised, with minute buds 

 covered with cinereo-pubescent caducous scales, and branchlets marked by conspicuous 

 leaf-scars. Leaves membranaceous, feather-veined, reticulate-venulose, deciduous. 

 Flowers pedunculate, nodding, purplish, bad-smelling; sepals ovate, smaller than the 

 petals, green, deciduous; petals imbricated in the bud, hypogynous, sessile, ovate or 

 obovate-oblong, reticulate-veined, accrescent, the three exterior alternate with the 

 sepals, spreading, those of the interior row opposite the sepals, erect, and much 

 smaller than those of the outer row; stamens linear-cuneate, densely packed on the 

 receptacle; filaments shorter than the fleshy connective; anther-cells separated on 

 the connective; pistils sessile on the summit of the receptacle, projecting from the 

 globular mass of stamens; ovary 1-celled; style oblong, slightly recurved toward 

 the apex and stigmatic along the margin; ovules 4-20, horizontal, 2-ranked on the 

 ventral suture, the raphe toward the suture. Fruit baccate^, sessile or stipitate, oval 

 or oblong, smooth. Seeds in 1 or 2 ranks, ovate, apiculate, compressed, marked at 

 the base by a large pale hilum. 



Asimina is confined to eastern North America. Six species are distinguished; of 

 these one is a small tree; the others are low shrubs of the south Atlantic and Gulf 

 regions. 



Asimina is from Asiminier, the old colonial name of the French in America for 

 the Pawpaw. 



1. Asimina triloba, Dunal. Pawpaw. 



Leaves obovate-lanceolate, sharp-pointed at the apex, gradually and regularly 

 narrowed to the base, when they unfold covered below with short rusty brown cadu- 

 cous tomentum and slightly pilose above, and at maturity light green on the upper 

 surface, pale on the lower surface, 10'-12' long, 4'-6' wide, with prominent midribs 



