34 



YOSEMITE NATURE NOTES 



BLACK LOCUST 

 Robinia pseudoacacia L. — Pea Family (Leguminosae) 



Although native primarily to the 

 Appalachian Mountain area, this tree 

 has been widely planted throughout 

 many parts of the United States. 

 Yosemite Valley was no exception 

 and those planted here during the 

 early days are now good sized trees. 

 They vary from six to fifteen inches 

 in diameter and, in some cases, are 

 from fifty to sixty feet high. 



The black locust can be easily rec- 

 ognized by the alternate, odd-pinnat- 

 ely compound leaves, which are 

 from eight to fourteen inches long, 

 and which bear seven to nineteen 

 sub-opposite rounded leaflets, each 

 one and one-half to two inches long. 



As this tree is a member of the 

 Leguminosae or pea family its flow- 

 ers and seed pods are characteristic 

 of that group of plants. The handsome 

 white clusters of pea-like flowers ap- 

 pear on the trees in June. Seeds, 

 borne in elongated, dark brown, 

 bean-like pods which are two to four 

 inches long, are mature by late sum- 

 mer or early fall. 



The trunk of this tree is short, di- 

 viding but a little way above the 

 ground into a number of stout branch- 

 es to form an open crown. The bark 

 is dark reddish-brown in color and 

 deeply fissured — the numerous ridges 

 having a characteristic twisted or 



Pholo by Brockman 



tolijgc and floucrs of black locust {Inch squares on background) 



