JUGLANDACE^. SILVA OF NORTH AMERICA. 



113 



JUGLANS. 



Flowers monoecious, apetalous ; calyx of the staminate flower 3 to 6-lobed, the 

 lobes imbricated in aestivation ; stamens 8 to 40 ; calyx of the pistillate flower 4-lobed, 

 the lobes imbricated in aestivation ; ovary inferior, 1-celled ; ovule solitary, erect. 

 Fruit, a nut inclosed in an indehiscent involucre. Leaves alternate, unequally pin- 

 nate, destitute of stipules, deciduous. 



Juglans, Linnseus, Gen. 291 (1737). — A. L. de Jussieu, Engler & Prantl Pfianzenfam, iii. pt. i. 24. — Baillon, 



Gen. 375. — Meisner, Gen. pt. ii. 54. — Endlicher, Gen. Hist. PL xi. 405. 



1126. — Bentham & Hooker, Gen. iii. 398. — Engler, Wallia, Alefeld, Bonplandia^ ix. 334 (1861). 



Resinous aromatic trees^ with sweet watery juice, furrowed scaly bark, handsome durable dark- 

 colored wood, stout terete branchlets, laminate pith, scaly buds, long stout flexible perpendicular roots 

 covered with thick bark, and few thick fibrous rootlets. Terminal buds short or elongated, usually 

 covered with two pairs of opposite scales often obscurely pinnate at the apex, those of the inner pair 

 accrescent, more or less leaf-like, often resembling the short-Hved scale-like upper leaves, and in falhng 

 marking the base of the branchlet with faint ring-like scars. Axillary buds formed before midsummer, 

 obtuse, slightly flattened, covered with four ovate rounded scales, superposed, two to four together, 

 decreasing in size from the upper to the lower, the scales closed or open during winter. Leaves alter- 

 nate, unequally pinnate or often equally pinnate by the suppression of the terminal leaflet, many- 

 foliolate, deciduous, the last leaf of the year sometimes reduced to a scale-like body and persistent 

 during the winter ; petioles elongated, terete, grooved on the upper side, gradually enlarged toward 

 the base, leaving in falling large conspicuous elevated obcordate three-lobed leaf-scars displaying three 

 equidistant U-shaped clusters of dark fibro-vascular bundle-scars, the basal cluster much larger than 

 the others j leaflets conduplicate in vernation, ovate, acute or acuminate, mostly unequal at the base, 

 membranaceous, serrate or entire, sessile or short-petiolulate, or the terminal leaflet raised on a long 

 slender stalk, penniveined, the veins arcuate and united near the margins and connected by reticulate 

 veinlets, often separating from the petiole in falling. Flowers proterandrous or proterogynous, opening 

 in the late spring after the leaves. The staminate in many-flowered elongated aments, soHtary or in 

 pairs from the lower axillary buds of the upper nodes, appearing from between the persistent bud-scales 

 in the autumn and remaining during the winter as short cones covered by the closely imbricated bracts 

 of the flowers, coated with tomentum, and beginning to elongate in early spring. Perianth sessile or 

 pediceUate, three to six-lobed in the axil of and adnate to an ovate acute bract free only at the apex. 

 Stamens eight to forty, inserted on the perianth in two or several ranks, those of the exterior rank 

 alternate with its lobes ; filaments free, abbreviated ; anthers erect, oblong, glabrous, two-celled, the cells 

 opening longitudinally and surmounted by a conspicuous dilated truncate or lobed connective. Ovary 

 wanting. Pistillate flowers in few-flowered spikes terminal on branches of the year, invested by a villous 

 involucre adnate to the ovary and formed by the union of the anterior bract, sometimes free nearly to 

 the base, and two lateral bractlets free only at the apex, and variously cut into a laciniate border shorter 

 than the erect lanceolate calyx-lobes inserted on the summit of the ovary. Stamens wanting. Pistil 

 composed of two median, or rarely of three, carpels j ovary inferior, one-celled ; style short ; stigmas 



