=Order=, _Juglandaceæ_ (Walnut family).--Medium to large deciduous trees with odd-pinnate leaves; leaflets from fifteen to twenty-one, serrate, mainly oblong and pointed. The sexes of flowers separate (monœcious) on the same tree, the males in pendulous green cylindrical catkins two to three inches long, solitary or in pairs, sessile,--not stalked, as in the hickories,--issuing from the one-year-old twigs, and at the upper edge of the scar left by the falling leaf of the previous season (Fig. 73), showing that the male organs emanate from an aggregation of bud-cells in the axils of the leaves during the preceding summer and autumn. Female flowers terminal on the new growth in spring, also single, in clusters, and occasionally in long pendulous racemes with a four-cleft calyx, four minute petals and two thick curved stigmas. Fruit round or oblong (Fig. 74); husk thin, drying up without opening by seams, as in the hickories. Shell of nut either rough and deeply corrugated, with sharp-pointed ridges, or quite smooth, with an undulating, wavy surface, very thick in some species and thin in others; kernel two- or indistinctly four-lobed, united at the apex, fleshy, rich and oily. [Illustration: FIG. 73. PERSIAN WALNUT, SHOWING POSITION OF SEXUAL ORGANS.] =History.=--The common walnut, so long and widely known in commerce under various names, such as Persian, English, French, Italian and European walnuts, also as Madeira nut, and recently Chile walnut, are now all believed to have descended from trees native of Persia, most plentiful in the province of Ghilan on the Caspian sea, between latitude 35° and 40°, hence the old Grecian name of the fruit, viz.: Persicon and Basilicon, or Persian Royal nut, probably because either introduced by the Greek monarchs, or sent to them by the Persian kings. Later,--according to Pliny,--the Greeks called the trees _Caryon_, on account of the strong scent of the foliage, and from this name Nuttall coined his word, _Carya_, for our indigenous hickories, as explained in the preceding chapter. It should also be noted here that the elder Michaux, in 1782-4, was the first modern botanist to visit the province of Ghilan, and he determined, by personal investigation, that this species of the walnut was really indigenous to that region of country, along with the peach and apricot. [Illustration: FIG. 74. BEARING BRANCH OF ENGLISH WALNUT.]