WALNUT. 237 



JUGLANDACEAE. WALNUT FAMILY. 



Trees with alternate, pinnately-compound leaves, no stipules. 

 Flowers monoecious; the staminate in catkins with or without 

 an irregular calyx and several stamens; the pistillate solitary or 

 in clusters of two to five, their common peduncle terminating the 

 shoot of the season; calyx, three to five lobed; stigmas, sessile, 

 two-lobed, persistent. Ovary one-celled or incompletely two to 

 four-celled, with a single ovule erect from its base; ripens into 

 a large fruit, the bony inner part of which forms the shell of the 

 nut and the fleshy outer part, the husk. Seed four-lobed, filled 

 with fleshy oily embryo and large crumpled or corrugated coty- 

 ledons. 



Genus JUGI,ANS. 



Leaves odd-pinnate with numerous serrate leaflets; petioles 

 long, grooved on the upper side, gradually enlarged towards the 

 base. In falling, the leaves expose large, conspicuous, elevated, 

 obcordate, five-lobed scars. Flowers monoecious, opening in 

 late spring after the leaves; the staminate in catkins, solitary or 

 in pairs from the wood of the preceding year, each with eight to 

 forty stamens on very short filaments and a three to six-lobed 

 calyx; the pistillate solitary or several in a cluster on a branch 

 of the season; calyx four-toothed, bearing in its sinuses four small 

 petals; stigmas two, somewhat club-shaped and fringed. Fruit 

 large, drupaceous, marked at the apex with the remnant of the 

 style and covered with a fibrous, spongy, somewhat fleshy, inde- 

 hiscent epicarp (shuck) and a rough, irregularly furrowed endo- 

 carp (shell); embryo edible. Trees with sweet, watery juice, 

 furrowed, scaly, resinous, aromatic bark and pith that separates 

 into thin transverse layers. To this genus belong our native 

 Black Walnut and Butternut, and the English Walnut (/. regia) 

 of commerce, which has been long in cultivation, and is probably 

 a native of Asia Minor. The Japanese use in large quantities a 

 walnut belonging to this genus. The species here described have 

 long tap roots and but few lateral roots. For this reason they do 

 not transplant easily except when very young, or unless the tap 

 roots are cut when the seedlings are small. In the latter case 



