130 WOODY PLANTS 



1. C. scoparius (L. ) Link. Scotch Broom. A shrub 1-2 m. 

 high, with glabrous stiff green branches; twigs finely granular, 

 almost winged on the ridges. Introduced from Europe and natu- 

 ralized (Fig. 171). 



ROBINIA L. (Leguminosae) 



Deciduous trees or shrubs. Twigs often prickly, more or 

 less angled, zigzag; pith round, continuous. Buds small, super- 

 posed, covered by the leaf-scar; terminal bud lacking. Leaf-scars 

 alternate, broadly triangular, consisting of a membrane that later 

 splits open, revealing the buds; bundle-traces 3; stipules modified 

 as bristles or prickles which enlarge and persist for several years. 



a. Twigs glabrous or nearly so 1. R. pseudo-acacia 



a. Twigs bristly, glandular or viscid 2. R. viscosa 



1. R. pseudo-acacia L. Black Locust. A tree to 25 m.high, 

 but generally smaller; bark rough, deeply furrowed, dark brown; 

 twigs moderate, somewhat zigzag, greenish to reddish-brown, 

 usually with two stipular spines at each node; pods dark brown, 

 5-10 cm. long, 10-12 mm. wide, often remaining on trees through 

 the winter. Woods and thickets, Georgia to Louisiana, north to 

 Pennsylvania, Indiana, and Oklahoma, now widely introduced and 

 naturalized (Fig. 172). 



2. R^ viscosa Vent. Clammy Locust. A small tree, to 12 m. 

 high, with dark red -brown glandular- viscid twigs; stipular spines 

 small or lacking; pods clammy. Dry woods, in the mountains. 

 North Carolina to Georgia and Alabama; cultivated northwards. 



WISTERIA Nutt. (Leguminosae) 



Twining deciduous shrubs. Stems moderate, somewhat fluted; 

 pith moderate, white or brown, round, continuous. Buds moderate, 

 sessile, oblong, acute, nearly surrounded by the outer scale. 

 Leaf-scars alternate, elliptical, raised, with a protuberance at 

 each side; bundle-trace 1; stipule-scars lacking. 



1. W_. frutescens (L. ) Poir. Wisteria. Stems up to 12 m. long; 

 branchlets glabrous or nearly so. Banks of streams and swamps, 

 on the coastal plain, Virginia to Florida and Alabama. 



ZANTHOXYLUM Gmel. (Rutaceae) 



Deciduous aromatic shrubs or small tree, armed with prickles 

 often paired at the nodes (as in Robinia) but not believed to be 



