16 HOUGH'S AMERICAN WOODS. 



wood occurs as threads or bundles running through a cellular, pith-like tissue so that 

 a transverse section exhibits the wood as dots and not in concentric rings. Leaves 

 mostly parallel-veined. Embryo with single cotyledon, or rarely two, and then alter- 

 nate and unequal. Parts of the flower generally in threes. In southern United 

 State and elsewhere in or near the tropics trees are found, such as the Palms, etc., 

 which belong to this class, but none that we have to do with at present. 



Exogenous plants are subdivided into two well-marked groups or sub- 

 classes AngiospermoB and Gymnospermce. The former includes by far 

 the greater part of the Flowering Plants, and most of the species repre- 

 sented in " American Woods " are representatives of it. 



ANGIOSPERMOB. 



Flowering, exogenous plants in which there is a complete pistil with 

 stigma and closed ovary containing ovules which develop into seeds at 

 maturity. This sub-class comprises many groups of plants known as 

 Orders, and such as are represented by plants which attain the dimen- 

 sions of trees, within the limits of the United States, we propose to con- 

 sider in the following pages : 



ORDER ANONACEAE: CUSTARD APPLE FAMILY. 



Leaves alternate, without stipules, feather- veined and entire, from naked buds. 

 Flowers solitary, in the axils of the leaves; sepals three; petals six in two rows, 

 thickish, valvate in the bud; stamens numerous, hypogenous, with very short fila- 

 ments and adnate anthers opening outwards; pistils several or many, separate or 

 coherent. Fruit fleshy or pulpy, with large anotropous seeds with crustaceous cov- 

 ering, minute embryo and ruminated albumen. 



Chiefly a tropical family composed of trees and shrubs having pulpy and usually 

 esculent fruit. 



GENUS ASIMINA, ADANS. 



Leaves as described for the order. Flowers in the axils of the leaves of the pre- 

 ceding year, with three sepals and six petals which develop after the bud opens, the 

 outer set longer than the inner; stamens numerous and packed in a spherical mass; 

 pistils several and distinct but only a few developing. Fruit oblong, pulpy and 

 containing several seeds. 



Shrubs and small trees. (Asimina is said to be from an Indian name, asimin.) 



76. ASIMINA TRILOBA, DTOAL. 



PAPAW, CUSTARD APPLE. 

 G-er., Dreilappiger Flachenbaum; Fr., Asiminier; Sp., Anona. 



SPECIFIC CHARACTERS: Leaves obovate-lanceolate, acuminate, entire, thin, cov- 

 ered with a rusty down at first (in common with the young shoots), but soon glab- 

 rous, from 6 to 12 inches in length and witli very short petioles. Flowers appear 

 early, rather before the leaves, drooping, with purplish brown (though quite vari- 

 able in color), veiny, roundish-ovate petals, the outer set being three or four times 

 as long as the sepals. Fruit ripening in September or October, oblong, irregular, 

 2-4 in. in length and about 1 in. in thickness, yellowish green, fragrant and contain- 

 ing a rich custard-like edible pulp with eight or ten large seeds. 



(The specific name, trildba, is the Latin for three-lobed.) 



