128 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. 



AMERICAN BLACK WALNUT. 



(Juglans nigra.) 



This is the native walnut of the Middle West, occurring in river 

 bottoms and valleys from western Massachusetts to Minnesota, south- 

 ward to Georgia, Florida, Mississippi, and Texas, and forming one of 

 the finest trees of Ohio, Illinois, Nebraska, Kansas, Kentucky, western 

 Pennsylvania and other portions of the Middle West. It is a tall, 

 erect-growing tree with a large, straight trunk covered with deeply- 

 furrowed, narrow-ridged bark. The fruit is large, with a thick husk, 

 containing a nut which is of brown or, when dry, nearly black color, 

 with a hard, thick shell marked on the surface with deep, narrow fur- 

 rows and prominent, irregular ridges. This tree is not native to Cali- 

 fornia, but was brought here by the first settlers from the East, and 

 has been planted quite abundantly since the early fifties. In California 

 the true eastern species is of very slow growth during its early years, 

 and is distinguished from all others by its very rough nuts. Other 

 conspicuous characteristics are the fact that it is extremely late in 

 coming out in the spring, the trees remaining bare and dormant long 

 after other walnuts are in full leaf, while at the same time, it is one 

 of the first to drop its foliage in the fall. Typical trees of the true 

 Juglans nigra, grown from seed introduced from various Middle West 

 States, may be found growing about almost all of the older towns of 

 the State, particularly in the central and northern portions. 



CALIFORNIA BLACK WALNUT. 



The first American explorers of California found growing here native 

 walnut trees which have been variously classified by botanists. Sereno 

 Watson 1 in 1875 described Juglans calif ornica as "A large shrub or 

 tree in the vicinity of San Francisco, growing 40 to 60 feet high and 

 2 to 4 feet in diameter, and ranging southward to Santa Barbara, 

 southern Arizona and Sonora." He includes in this species what 

 Torrey had previously described as Juglans rupestris, var. major, 

 stating that "The more eastern Juglans rupestris is but 6 to 20 feet 

 high, with more numerous and usually more acuminate leaflets," etc. 

 To the latter species he also ascribes a smaller, thicker walled nut than 

 that of calif ornica. Most of the standard works, such as those of Sar- 

 gent and Britton, follow this arrangement, giving the one species Jug- 

 lans calif ornica for this State, with a range extending over most of 

 the State. Britton 2 states, for instance, page 220, that "This walnut 



: Proc. Am. Acad. Arts and Sc. Vol. 10 :349, 1875. 

 2 North American Trees. 



