68 



Annonaceae. 



>v 



Asimina. Papaw. 

 (Family Annonaceae). 



Small trees or arborescent 

 shrubs: deciduous. Twigs round- 

 ed, moderate. Pith roundish, 

 white, continuous with firmer 

 greenish diaphragms, or becom- 

 ing brownish and chambered in 

 age. Terminal bud clearly naked, 

 larger, the lateral obliquely super- 

 posed with the uppermost globose 

 and stalked when a flower-bud or 

 oblong and subsessile when a leaf- 

 bud. Leaf-scars alternate, 2- 

 ranked, half-round becoming 

 broadly crescent- or horseshoe- 

 shaped by rupture of the mem- 

 branous top which at first covers 

 the smaller buds: bundle-traces 5 

 or 7, sometimes doubled: stipule- 

 scars lacking. 



The "papaw" of the northern 

 States and the related custard 

 apples, sweet-sops, sour-sops, cherimoyas, etc., of the 

 tropics, which belong to! the related genus Annona, 

 illustrate a type of pith which recurs here and there 

 (e. g. in Magnolia and Nyssa), in which cross-bands of firmer 

 cells are found at intervals. In the present treatment con- 

 tinuous pith of this kind is spoken of as diaphragmed, in 

 contrast with the chambered pith of Juglans, etc., where the 

 cross-bands remain but the softer parts of the pith have 

 disappeared. Asimina is somewhat puzzling in this respect, 

 for the firm diaphragms are not always readily seen when a 

 young twig is split. 

 Twigs and especially buds red-hairy. A. triloba. 



