THE EASTERN SHRUBBY SPECIES OF ROBINIA 



By W. W. Ashe 



The eastern shrubby species of Robinia are separated from Roi- 

 inia pseudo-acacia L. (which has a smooth flat pod and white fragrant 

 flowers) by having pods prickly, hispid, bristly or glandular and 

 pink or purplish flowers. 



Key to Eastern Shrubby Species of Robinia 



Al. = alleghanian ; C. = Carolinian. Au. = austroriparian. 

 TAvigs, petioles and pedicels viscid, pod flat; margined (Al. and C). 



Twigs (often petioles, etc.) covered with viscid secretion.... (1) R. viscosa Vent. 

 Twigs (often petioles, etc.) with short gland-tipped viscid bristles 



(2) B. viscosa var. hardwegii (Koeh.) Ashe 

 Twigs never viscid. 



Peduncles, twigs and shoots not hispid, rarely hispidulose. 



Leaves, twigs and peduncles eventually glabrous or nearly so. 

 Flowers rose-purple, never fragrant ; pods thick. 



Flowers about 15 mm. long, leaflets lance ovate (Al.) 



(3) B. Icelseyi Cr. 

 Flowers more than 17 mm. long, leaflets elliptic (Al.) 



(4) B. hoyntonii Ashe 

 Flowers pale lilac or pinkish, fragrant; pods flat (Au.) 



(5) B. murgaretta Ashe 



Leaves and inflorescence canescent (Au.) (6) B. elliottii (Chapm.) Ashe 



Peduncles and vigorous shoots usually hispid (in 8 sometimes pubescent), 

 pods thick. 

 Flowers more than 20 mm. long, racemes few-flowered (Al.) 



TwigS densely hispid (7) B. hispida L. 



Tvidgs sparingly hispid, often merely appressed pubescent. 



(8) i?. grandiflora Ashe 

 Flowers less than 20 mm. long, twigs never densely bristly 

 Bristles on twigs short, gland-tipped; 6-18 flowered (C.) 



(9) B. longiloha Ashe 

 Twigs usually glabrate; racemes 3-6 flowered (Au. & C.) 



(10) B. nana (Ell.) Spach. 



R. viscosa var. hardwegii (Koeh.) n. c. — R. hardwegii Koeh. 



This plant is frequent around Highlands, North Carolina, associ- 

 ated with the form which has viscid twigs. A few short gland- 

 tipped hairs are to be found on nearly every plant with viscid secre- 

 tion and as the pubescence becomes more dense there seems to be 

 less of the viscid secretion, so that the form with the viscid secretion 

 gradually passes into the form having viscid pubescence. 



[175] 



