222 NORTH AMERICAN FLORA [Volume 24 



Leaflets oblong to oval, paler beneath; pod glandular -hispid as well as 

 hirsutulous. 

 Leaflets and rachis strigose-puberulent ; pod about 1 em. broad. 

 Calyx-lobes longer than the tube, long-acuminate; leaflets 



oblong or elliptic; spines straight. 16. R. luxuriant. 



Calyx-lobes shorter than the tube, abruptly acute; leaflets oval; 



spines somewhat curved. 17. R. breviloba. 



Leaflets and rachis loosely short-villous; calyx-lobes acute or short 



acuminate, about equaling the tube; pod about 14 mm. broad. 18. R. subvelutina. 



IV. Viscosae 



Leaflets puberulent or, glabrate on both sides; branches and peduncles 



with subsessile glands, not densely puberulent. 19. R. viscosa. 



Leaflets densely villous beneath; branches and peduncles with stalked 



glands, as well as densely puberulent. 20. R. Harlwigii. 



1 Robinia Pseudo-Acacia L. Sp. PI. 722. 1753. 



Robinia Acacia L. Syst. ed. 10 1161. 1759. 



Pseudo-Acacia [" Pseudacacia"] odorata Moench, Meth. 145. 1794. 

 Robinia fragilis Salisb. Prodr. 336. 1796. 



A tree, 20-27 m. high; branches terete or somewhat angled, more or less silky when very 

 young, green, turning reddish in autumn; stipules subulate, developing into spines 3-25 mm. 

 long; leaves 2-3 dm. long; petiole and rachis puberulent or glabrate; leaflets 7-19 fin cultivated 

 forms 1-5), oval or ovate, rounded or truncate and mucronate at the apex, acute or obtuse at 

 the base, blue-green above, pale beneath, puberulent on both sides or glabrate in age, 3-5 cm. 

 long, 1-2 cm. wide; petiolules 2-4 mm. long; racemes 1-1.5 dm. long, lax, puberulent; pedicels 

 about 1 cm. long; bracts minute, caducous; calyx silky-puberulent, ciliolate on the margin; 

 tube 5 mm. long, campanulate, the upper lobes united high up, broadly triangular, fully 1 mm. 

 long, the lateral ones deltoid, the lowest one lanceolate, 2 mm. long; corolla white. 15-22 mm. 

 long; banner rounded-obovate, emarginate; wings obliquely obovate, with a prominent tri- 

 angular obtuse basal auricle; blades of the keel-petals lunate, with a smaller basal auricle; 

 pod short-stipitate, 6-10 cm. long, 10-12 mm. broad, glabrous, 4-16-seeded, the seed-bearing 

 suture narrowly winged; seeds 5.5 mm. long. 3 mm. broad, oblique. 



Type locality: Virginia. 



Distribution: Pennsylvania to Arkansas. Louisiana, and Georgia; extensively cultivated and 

 escaped throughout the United States and southern Canada. 



Illustrations: Wangenh. Beytr. Nordam. Holz. pi. 7; Schmidt, Baumz. 1: pi. 32; Gaert. 

 Fruct. pi. 145; Oelhafen, Abbild. 2: pi. 42; Nouv. Duham. 2: pi. 16; Lam. Tab. Encyc. pi. 606; f. 1; 

 Michx. f. Hist. Arb. Am. 3: 245, pi. 1; N. Am- Svlva pi. 76; Audubon, Birds pi. 104; Loud. Arb. 

 pi. 83-86; f. 305; Baillon, Hist. PI. 2:/. 159; Emerson, Trees Mass. ed. 2. 2: 523. pi. 1; Sargent. Silva 

 pi 112. 113; Medic. Akazien pi. 1. 2; Rev. Hortic. 1863: pi. opp. 150; 1875: pi. opp. 191 ; 111. Hortic. 

 12: pi. 427; Garden 9: pi. opp. 36; 34: 174; Britton, N. Am. Trees /. 511, 512; Rogers, Tree Hook 

 pi. opp. 337; Sargent, Man. f. 472; Hough. Handb./. 341,342,343; Keeler, Nat. Trees 99, 100, 101; 

 Lounsberry, Guide Trees pi. 10S; Newhall. Trees N. Am./. 96; Am. Jour. Bot. 11: pi. 34 R. 



Robinii Boyntonii X Pseudo-Acacia. See under R. Boyntonii. 



Robinia hispida X Pseudo-Acacia. See under R. hispida. 



Robinea luxurians X Pseudo-Acacia. Robinia Holdtii Beissn. Mitt. Deuts. Dendr. Ges. 11: 

 117. 1902. Robinia neomexicana X Pseudo-Acacia, I.e., as synonym. 1902. Robinia coloradensis 

 Dode, Bull Soc. Bot. France 55: 650. 1909. Leaflets larger and darker and firmer than those 

 of R. Pseudo-Acacia; corolla light-pink or rose, or nearly white (R. Holdtii briizensis Spaeth, Garten- 

 flora 52: 557. 1903), the pod with scattered glands. 



Robinia Pseudo-Acacia X viscosa. See under R. viscosa. 



2. Robinia Pringlei Rose, Contr. U. S. Nat. Herb. 12: 274. 1909. 



A medium-sized tree, apparently unarmed ; branches terete, puberulent when young, soon 

 glabrous; stipules subulate, 3 mm. long; leaves about 2 dm. long; rachis puberulent, grooved 

 above; leaflets 1 3->15, oval, rounded at both ends, 2.5-5 cm. long, 1.5-3 cm. wide, puberulent 

 on both sides, pale beneath, mucronate; racemes 1-1.5 dm. long, puberulent; bracts minute; 

 pedicels 10-12 cm. long; calyx puberulent, ciliate on the margins, the tube 5 mm. high, 7 mm. 

 broad, the upper 2 lobes broadly triangular-ovate, united to near the top, the lower three sub- 



