This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol2", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Small trees, or shrubs, with alternate leaves and lateral or axillary nodding flowers. Buds naked. Sepals 3, ovate, valvate. Petals 6, arranged in 2 series, valvate or imbricated in the bud, those of the outer series the larger when mature. Receptacle subglobose. Stamens and carpels 3-15. Style oblong, stigmatic along the inner side; ovules numerous, in 2 rows. Fruit, large fleshy oblong berries. Seeds large, flat, horizontally placed, enclosed in fleshy arils. [From the aboriginal name Assimin.]
About 7 species, natives of eastern and southeastern North America, the following typical.
Annona triloba L. Sp. Pl. 537. 1753. Asimina triloba Dunal, Mon. Anon. 83. 1817.
A tall shrub or tree 10°-45° high, the trunk 5'-10' in diameter. Shoots and young leaves dark-pubescent, becoming glabrous at maturity; leaves obovate, acute, 6'-12' long, cuneate or rounded at the base; petioles 4"-6" long; flowers axillary, on shoots of the preceding year, appearing with the leaves, I'-1 1/2" in diameter, dark purple; sepals ovate, 4"-6" long, densely dark-pubescent, as are the short peduncles; outer petals spreading, nearly orbicular, slightly exceeding the ovate inner ones; stamens numerous, short; fruit a fleshy berry, 3'-7' long, 1'-2' thick, sweet, edible and brown when ripe, pendulous, several on a thick peduncle.
Along streams, southwestern Ontario and western New York, Pennsylvania and western New Jersey to Michigan, Florida, Kansas and Texas. March-April, the fruit mature in October. Wood light, soft, weak, greenish-yellow. Weight per cubic foot 24 lbs. Custard-apple. Fetid shrub.