1921| REIIDER, NEW SPECIES, VARIETIES AND COMBINATIONS 39 



mm. broad, keel 1.5 cm. long without the claw; staminal tube 1.5 cm. 

 long; ovary tuberculate, the tubercles occasionally with a hair-like ap- 

 pendage. Pod 5-6 cm. long and about 1 cm. broad, roughened by small 

 tubercles partly bearing short prickles less than 1 mm. long; seeds about 

 4 mm. long, obliquely ellipsoid, slightly compressed, dull olive-green, 

 mottled with black. 



Cultivated at Rochester, New York; specimen examined: Durand-Eastman 

 Park Nursery, June 6 and July 30, 1919, June 4 and October 10, 1920, B. H. 

 Slavin (No. 3, type, and No. 4; flowers and fruit; Nos. 1, 2, 5 and 6; flowers and 

 mature leaves). 



This new hybrid originated at the Durand-Eastman Park, Rochester, 

 New York, from seed of R. Kelseyi Hutchins, collected in 1914 by Mr. 

 13. H. Slavin. From this species the hybrid is easily distinguished by 

 the larger and broader often obtuse and even emarginate leaflets, by the 

 larger raceme with a slightly villose rhachis destitute of glandular hairs, 

 by the broader calyx and by the fruit entirely destitute of glandular 

 hairs being only roughened by minute tubercles. From R. Pseudoacacia 

 L. which is without doubt the other parent it differs chiefly in the narrower, 

 generally ovate-oblong leaflets often acutish and but rarely emarginate, 

 nearly glabrous when unfolding, in the shorter comparatively few-flowered 

 racemes, shorter pedicels, rosy pink flowers and in the tuberculate fruit. 

 It has some resemblance to R. Margaretta Ashe, which possibly is a hy- 

 brid between R. Pseudoacacia and R. hispida, but R. Margaretta may be 

 distinguished by the broader, obtuse leaflets silky pubescent beneath 

 when young and by the longer racemes with a sparingly glandular-pilose 

 rhachis and pedicels. 



Robinia Slavinii is apparently similar in general appearance to /?. Kelseyi 

 but of more vigorous growth and is tree-like in habit; if the rosy-pink 

 flowers are produced as profusely as in R. Kelseyi, it will be a desirable 

 ornamental plant. 



X Robinia ambigua Poiret in Encycl. M6th. SuppL iv. (590 (1816) 

 (R. pseudoacacia X viscosa). — R. dubia Foucault in Jour. Bot. Appl. n. 

 204 (1813), not Poiret.— R. hybrida Audibert ex De Candolle, Prodr. n. 

 262 (1825), as synon. — R. intermedia Soulange-Bodin in Ann. Soc. 

 Hort. Paris, n. 43 (1828). 



This hybrid Robinia was raised from seed of R. viscosa by Emmanuel 

 de Foucault and flowered for the first time in 1812. The name R. dubia 

 which has been used by most authors for this form, should be replaced 

 by R. ambigua on account of the older R. dubia Poiret (in Encycl. M£th. 

 vi. 227) of 1804 which must be considered a valid name from a nomen- 

 clatorial point of view, though it is now referred to the genus Sabinea. 

 Loudon and also Schneider and A. Henry mention as possibly belonging 

 here R. echinata Miller, Diet. ed. 8 (1768), but the descriptive phrase 

 "leguminibus echinatis" hardly applies to this hybrid, and, more- 

 over, R. viscosa Vent, one of its supposed parents was not introduced until 



