Part 4, 1924] 



FABACEAE: GALEGEAE 



18. ROBINIA L. Sp. PL 722 1753. 



Pseudo-Acacia (Tourn.) Medic. Vorl. Churpf. Phys. Ges. 2: 364. 17S7. 



Trees or shrubs. Leaves odd-pinnate, with setaceous or spinose stipules, and small 

 stipels. Flowers in axillary racemes, the bracts caducous. Calyx more or less 2-lipped; 

 upper lip with 2 broad short teeth united to near the tip, the lower one more deeply 3-lobed. 

 Corolla white or purple. Banner with a broad blade and short claw, reflexed. Wings free, 

 clawed, the blades obliquely oblong or obovate, with a basal auricle. Keel-petals obtuse, 

 incurved, the blades obliquely obovate, with a basal auricle, united from the middle to the tip. 

 Stamens more or less monadelphous, the upper filament free at the ba$e, more or less united 

 with the sheath at the middle. Ovary more or less stipitate, many-ovuled; style inflexed, 

 short-hairy towards the apex; stigma terminal, minute. Pod linear, flat, 2-valved, continuous 

 within, narrowly winged or merely ridged along the upper suture. Seeds oblong, oblique, 

 without strophiole, but with a rather slender funicle. 



Type species, Robinia Pseudo-Acacia L. 



Flowers white or rarely pink, on drooping peduncles; pod glabrous, broadly 



wing-margined on the seed-bearing suture; calyx-lobes short, acute. 

 Flowers pink to rose-purple on erect or spreading peduncles; pod usually 

 glandular-hispid, in no. 14 hirsutulous, and in no. 13 glabrous, but the 

 wing-margin always very narrow or obsolete; calyx-lobes longer, 

 usually more or less acuminate. 

 Bracts inconspicuous, small or narrow, early caducous; bristles on the 

 branches and peduncles, if any, rather long and with incon- 

 spicuous gland-tips. 

 Calyx rounded at the base; sinuses between the lobes open; bracts 



linear or subulate; spines weak or none. 

 Calyx acute at the base; sinuses between the lobes narrow; bracts 

 short and broad; spines stout. 

 Bracts conspicuous, lanceolate, caudate-acuminate, longer than the 

 calyx; branches and peduncles densely glandular, with sessile or 

 short-stalked, conspicuous glands; leaflets 11-27. IV. Viscosae. 



I. Pseudo-Acaciab. 



II. Hispidae. 

 III. Neomexicanae. 



I. PSEUDO-ACACIAE 



Lowest calyx-lobe lanceolate, longer than the rest. 

 Lowest calyx-lobe deltoid, equaling the lateral one 



1. R. Pseudo-Acacia. 



2. R. Pringlei. 



II. Hispidae 



Branches not at all bristly, the peduncles not hispid or slightly so with 

 short hairs. 

 Leaflets oblong to oval. 



Branches, peduncles, and lower surface of the leaves short-villous, 

 somewhat canescent when young; peduncles not at all glandular- 

 hispid. 

 Branches, peduncles, and leaves finely puberulent when young and 

 glabrate; peduncles somewhat glandular-hispid. 

 Plant 1.5-2 m. high; calyx-lobes not longer than the tube. 

 Plant about 3 dm. high; calyx-lobes longer than the tube. 

 Leaflets lanceolate. 

 Branches and peduncles more or less hispid. 



Branches with rather few and short glandular bristles. 

 Branches usually copiously glandular -bristly with long hairs. 



Branches, leaf-rachis, and peduncles rather densely pubescent. 

 Leaflets broadly oval, rounded at the apex. 

 Leaflets ovate, acutish or obtuse at the apex. 

 Leaflets decidedly villous beneath. 

 Leaflets glabrate on both sides. 

 Branches, leaf-rachis, and peduncles merely hispid, or with a few 

 scattered hairs. 

 Leaflets oval, rounded at the apex. 



Bristles 1-2 mm. long; spines usually present. 

 Bristles 3-5 mm. long; spines usually wanting. 

 Leaflets lanceolate or ovate, acute at the apex. 



3. R. Elliotiii. 



4. R. Boynloni. 



5. R. nana. 



6. R. Kelseyi. 



7. R. longiloba. 



8. R. grandi flora. 



9. R. speciosa. 

 10. R. pallida. 



11. R. pedum ulata. 



12. R. hispida. 



13. R.fertilis. 



III. Neomexicanae 

 Pod glabrous; leaflets oval or elliptic, rather thin; spines small. 

 Pod hirsute to glandular-hispid; leaflets firmer; spines usually stout. 



Leaflets lanceolate or ovate, bluish-green on both sides; pod merely 

 hirsutulous, gradually acute. 



14. R. Rusbyi. 



15. R. neomexicana. 



