HYBRIDS OF JUGLANS. 35 



HYBRIDS OF JUGLANS. 

 LEAVES OF THE HYBRIDS. 



JUGLANS CALIFORNICA X JUGLANS NIGRA. 



The walnut hybrid of this parentage was formed by Mr. Burbank in 

 1878 and is known as the "RoyaL" One specimen of the first generation, 

 which is the sole representative of this generation, is now growing- at the 

 Sebastopol ranch of Mr. Burbaiik. It is a very handsome tree, about 20 

 meters high, with a wide-spreading top. Some second and some third 

 generation seedlings, the latter known as the "Beeson" walnut, are grow- 

 ing- near the Royal at Sebastopol. 



The Royal is distinguished by its rapid growth, by the fine grain of the 

 wood, and by the relatively wide annual rings of growth. The second 

 and third generation seedlings are extremely variable. This is noted in 

 size, in -vigor of the plants, and in the color, size, texture, and other char- 

 acters of the leaves. The Royal fruits abundantly; the fruiting character 

 of the later generations is not known. 



The leaves are composed of from 5 to 9 or more pairs of leaflets, which 

 may be strictly opposite on the rachis or may be more or less in alternation 

 (plate 4). The terminal leaflet is usually smaller than the other leaflets, 

 although it may also be larger than they are. It is generally single, but 

 occasionally a doubling is to be seen. In form the leaflets vary from lan- 

 ceolate, with a somewhat attentuate apex, to broadly ovate with an apex 

 which is acuminate. The bases may be either abrupt or even cordate. The 

 leaflets are serrate and exhibit all grades between fine and coarse serration. 

 The surface of the leaves is either smooth or roughened, the veins of the 

 dorsal surface may be either sunken or may be raised — generally the latter. 

 As a whole, any type of leaflet, or quality appertaining to a leaflet, holds 

 throughout all the other leaflets of the leaf. 



So far as the general observations on the leaves of the three generations 

 of the walnut hybrid go, the leaves show some grade of intermediacy. No 

 leaf was seen which was not distinguishable from the leaves of either of 

 the pure race, and all of the leaves examined showed characters of both. 

 How far this remark will be good when each second or third generation 

 plant is studied separately is not known. 



JUGLANS CALIFORNICA X JUGLANS REGIA. 



This walnut hybrid, known as the "Paradox," originated from a cross 

 made by Mr. Burbank in 1887. Four trees of the first generation are at 

 present growing in the street in front of the experimental tract of Mr. 

 Burbank in Santa Rosa. vSeedlings of the second (and third) generation 

 are at the Sebastopol ranch. The first-generation trees are about 28 

 meters high and about 25 meters spread. The bole of one of these trees, 

 at a point 1.5 meters above the surface of the ground, measured 30 cm. in 



