522 NEW ENGLAND TREES IN WINTER. 



COMMON LOCUST 



Black, Yellow or White Locust, Locust, Acacia. 

 Robinia Pseudo-Acacia L. 



HABIT Generally a small tree 20-35 ft. or occasionally 50-75 ft. in 

 height with a trunk diameter of eight inches to 2* ft.; trunk erect or 

 in-lined, frequently dividing- into a number of ascending limbs with 

 slender scraggly branches forming a narrow oblong open head; often 

 spreading by underground stems and forming thickets of small trees. 

 A rapidly growing tree but short lived and subject to the attacks of 

 borers. 



BARK Rough even on young trunks, dark reddish to yellowish- 

 brown, becoming deeply furrowed into rounded ridges, not flaky. 



TWIGS Rather slender, brittle, often zigzag, light reddish to green- 

 ish-brown, smooth or nearly so. more or less angled with decurrent 

 ridges from base and outer angles of leaf-soars, generally spiny with 

 paired stipular prickles at nodes. LENTICELS pale, scattered. PITH 

 wide, more or less angled. 



LEAF-SCARS Alternate, more than 2-ranked, generally large and 

 conspicuous, inversely triangular to pentagonal, raised, covering the 

 buds. STIPULES in the form of prickles, sometimes poorly developed 

 or entirely lacking. BUNDLE- SCARS 3. 



BUDS Terminal bud absent; lateral buds minute, rusty-downy, 3-4 

 superposed, generally close together, enclosed in a rusty-downy cavity 

 below the leaf-scar which cracks between the bundle-scars at the 

 development of a branch usually from the uppermost bud exposing the 

 long rusty hairs attached to under side of the three persistent lobes 

 of the leaf-scar; on rapidly grown shoots, the uppermost bud often 

 develops into a branch the first season, which may be rudimentary and 

 deciduous, leaving a small scar above leaf-scar. 



FRUIT A dark brown, flat pod, 5-10 cm. long, containing 4-8 small 

 brown mottled flatish seeds, persistent on the tree throughout the 

 winter. 



COMPARISONS The paired prickles at the nodes form the most 

 striking character of the Common Locust but since they are absent on 

 some twigs and entirely lacking on certain varieties, the hidden closely- 

 packed downy buds must be taken as the chief distinguishing features. 

 They separate the Common Locust from the Honey Locust when the 

 characteristic branched thorns are not present on the latter species. The 

 Clammy Locust [Robinia viscosa Vent.] is a small southern tree fre- 

 quently cultivated and established at many points throughout New 

 England. It has the general characters of the Common Locust but 

 the stipular prickles are less well developed and its twigs are covered 

 with a sticky glandular coating. The Bristly Locust [Robinia hispida 

 L.] is a mere shrub with twigs beset with bristly hairs but without 

 stipular prickles. The Prickly Ash or Toothache Tree [Zanthoxvlon 

 americanum L.], a shrub occurring throughout New England, resembles 

 the Locust in its stipular prickles (lower twig in plate). It is readily 

 distinguished from the Locusts, however, by the red downy exposed 

 clustered buds, the presence of a terminal bud and the pungent flavor 

 of its twigs. 



DISTRIBUTION In its native habitat growing upon mountain slopes, 

 along the borders of forests, in rich soils. Naturalized from Nova 

 Scotia to Ontario. Native from southern Pennsylvania along the 

 mountains to Georgia; west to Iowa and southward. Formerly much 

 planted as an ornamental and timber tree; more cultivated in Europe 

 than any other American tree. 



IN NEW ENGLAND Maine thoroughly at home, forming wooded 

 banks along streams; New Hampshire abundant enough to be reckoned 

 among the valuable timber trees; Vermont escaped from cultivation in 

 many places; Massachusetts. Rhode Island common in patches and 

 thickets and along the roadsides and fences. 



IN CONNECTICUT Frequent as an escape from cultivation. 



WOOD Heavy, exceedingly hard and strong, close-grained, very 

 durable in contact with the soil, brown or rarely light green, with 

 pale yellow sapwood of two or three layers of annual growth; exten- 

 sively used in shipbuilding for all sorts of posts, in construction ana 

 turnery; preferred for tree nails and valued as fuel. 



