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..
Trees or shrubs, spreading freely from undergound parts, with odd-pinnate leaves, and axillary or terminal racemes of showy flowers. Stipules small, often spiny. Petioles slightly dilated at the base, enclosing the buds of the next year. Calyx-teeth short, broad, the 2 upper somewhat united. Standard large, reflexed, not appendaged; wings oblong, curved; keel curved, obtuse. Stamens diadelphous; anthers uniform, or the alternate ones smaller. Ovary stalked; ovules 00. Pod flat, linear, not septate between the seeds, margined along the upper suture, tardily 2-valved. [Name in honor of John and Vespasian Robin, who first cultivated the Locust-tree in Europe, 1550-1629.]
About 8 species, natives of North America and Mexico. Type species: Robinia Pseudo-Acacia L.
Twigs, petioles and pods glabrous; flowers white: a tree.
Twigs and petioles glandular; pods hispid; flowers pinkish: a tree.
Robinia Pseudo-Acacia L. Sp. Pl. 722. 1753. Pseudo-Acacia odorata Moench, Meth. 145. 1789.
A large tree with very rough bark, maximum height of about 8o° and trunk diameter of 3 1/2°, rarely shrubby. Twigs and foliage nearly glabrous; stipules often spiny; leaflets 9-19, stalked, ovate or oval, mainly rounded at the base, obtuse or emarginate and mucronulate at the apex, entire, 1'-2' long; stipels small, setaceous; racemes loose, drooping; pedicels slender, 3"-6" long; flowers white, fragrant, 7"-10" long, the standard yellowish at base; pod glabrous, 2-4' long, about 6' wide, 4-7-seeded.
Monroe Co., Pa., south, especially along the western slopes of the mountains, to Georgia, west to Iowa, Missouri and Oklahoma. Extensively naturalized elsewhere in the United States and eastern Canada and in Europe. Wood strong, very durable, greenish brown, the sap-wood yellow; weight per cubic foot 46 lbs. Much used for posts, in ship-building, and especially for tree-nails. Called also white, yellow, black, red-flowering or green locust. Honey-, pea-flower or post-locust. Silver-chain. May-June.
A small tree, with rough bark, maximum height about 400 and trunk diameter 10'. Twigs and petioles glandular-pubescent, viscid; stipules short, sometimes spiny; leaflets 11-25, stalked, obtuse and mucronate at the apex, mostly rounded at the base, ovate or oval, 1'-2' long, thicker than those of the preceding species; stipels small, subulate; racemes rather dense, often erect; pedicels 2"-4" long; flowers pinkish, 9"-12" long, not fragrant; pod 2'-4' long, about 6" wide, glandular-hispid.
Mountains of Virginia to Georgia. Escaped in the Middle States and north to Nova Scotia. Wood brown, the sap-wood yellow; weight per cubic foot 50 lbs. Rose-flowering or red-locust. June.