Locust 553 



smooth, short-stalked in the persistent calyx, 4 to 8 cm. long, 8 to 10 mm. wide, 

 tipped with the persistent subulate style, and contains few oblong flattened seeds 

 without endosperm. 



The name Cladrastis is Greek, signifying brittle branches. The wood is yellow, 

 hard, strong, with a specific gravity of about 0.63, and has a limited use for gun- 

 stocks. A yellow dye is extracted from it. The tree is desirable for lawn and 

 park planting as far north as New York and central Ohio; it is also called Yellow 

 locust. Yellow ash and Gopher- wood. 



III. THE LOCUSTS 



GENUS ROBDJIA LINN^US 



lOBINIA comprises about 7 species of trees or shrubs confined to 

 North America. Fossil remains referred to the genus, however, have 

 been found in central Europe. 



They have slender zigzag twigs and small naked buds. The 

 leaves are alternate, unevenly pinnate, the nearly opposite leaflets without glands; 

 the stipules become spinescent. The flowers are on long pedicels in short nod- 

 ding racemes in the axils of the leaves, with early deciduous bractlets; the calyx is 

 bell-shaped, 5-toothed, the upper teeth shortest and somewhat united ; the standard 

 is broad and reflexed; wings curved and separate; keel petals curved, united 

 below; stamens 10, inserted with the petals, 9 of them united at the base, their 

 anthers all ahke, or nearly so, ovate; the ovary is stalked, linear-oblong; style awl- 

 shaped; stigma small; ovules many. The fruit is a many-seeded, flat, 2-valved 

 narrow legume, wing-margined on one edge, short-stalked, membranous, smooth 

 or prickly; the seeds are obhquely placed, oblong with a hard coat, thin endo- 

 sperm and large embryo. 



The name is in commemoration of Jean Robin (1550-1629) and his son Ves- 

 pasien (1579-1660), distinguished Paris botanists. The type species is R. Pseud- 

 acacia. In addition to the 3 arborescent species, 4 shrubby ones occur in our area. 

 The trees are much ravaged by the locust borer. 



Racemes loose; pods smooth; eastern tree. i. R. Pseudacacia. 

 Racemes dense; pods glandular-hispid. 



Twigs viscid; eastern tree. 2. R. viscosa. 



Twigs not viscid; southwestern tree. 3. R. neo-mexicana. 



I . LOCUST — Robinia Pseudacacia Linnaeus 



This well-known tree is native in the mountains from Pennyslvania to Georgia, 

 and perhaps westward to Iowa and Kansas. It is widely naturalized throughout 

 the eastern United States and in Canada and much planted in Europe and in the 

 western States. 



The trunk is usually divided into several leading branches; these are slender, 



