576 TREES OF NORTH AMERICA 



conspicuous midribs. Flowers on stout pedicels rather longer than the calyx, in 

 short axillary few-flowered hoary-canescent racemes, with acute minute bracts and 

 bractlets deciduous before the expansion of the flowers; calyx hoary-canescent, the 

 lobes ovate, obtuse, almost equal, the two upper connate nearly throughout; disk 

 cupuliform, adnate to the tube of the calyx; corolla papilionaceous; petals unguicu- 

 late, purple or violet, inserted on the disk; standard orbicular, deeply emarginate, 

 reflexed, furnished at the base of the blade with two infolded ear-shaped append- 

 ages covering 2 prominent callosities; wings oblique, oblong, slightly auriculate 

 at the base of the blade on the upper side, free, as long as the broad obtuse incurved 

 keel-petals; stamens 10, the superior one free, filling the slit in the tube formed by 

 the union of the others; filaments filiform; anthers of the same length, oblong, uni- 

 form; ovary sessile or slightly stipitate, pilose; style inflexed, bearded above the 

 middle; stigma thick and fleshy, depressed-capitate; ovules numerous, suspended 

 from the inner angle of the ovary, superposed. Legume oblique, compressed, gland- 

 ular-hairy, light brown, 2-valved, often tipped with the remnants of the long per- 

 sistent style, 1-5-seeded, the valves thick and coriaceous, becoming unequally and 

 interruptedly convex at maturity. Seeds broadly ovate, slightly angled on the ven- 

 tral side, suspended by short thick funicles, without albumen; seed-coat thin, mem- 

 branaceous, bright chestnut-brown and lustrous; embryo filling the cavity of the 

 seed; cotyledons thick and fleshy, accumbent on the short incurved radicle. 



The genus is represented by a single species of southern Arizona, California, and 

 northwestern Mexico. 



Olneya is in memory of Stephen T. Olney (1812-1878), author of a catalogue of 

 the plants of Rhode Island. 



1. Olneya Tesota, Gray. Ironwood. 



Leaves l'-2^-' long, with leaflets ^'-f in length, appearing in June and persist- 

 ent until the following spring. Flowers unfolding with the leaves, nearly ' long. 



Fruit light brown, very glandular, fully grown at midsummer, ripening before the 

 end of August, 2'-2^' long. 



A tree, sometimes 25-30 high, with a short trunk occasionally 18' in diameter 

 and usually divided 4-6 above the ground into a number of stout upright branches, 



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