JUGLANDACEAE 333 



gynoecium: calyx partially adnate to the gynoecium. Fruit drupe-like, the nut 

 enclosed in an indehiscent or dehiscent husk. Seed oily. 



Family 1. JUGLANDACEAE Lindl. Walnut Family. 

 Characters of the order. 



Staminate aments stout, simple, sessile or short-stalked: husk indehiscent: nut sculp- 

 tured. 1. JUGLANS. 



Staminate aments slender, branched, long-stalked: husk dehiscent: nut not sculptured. 2. Hicoria. 



1. JUGLANS L. 



Trees often subglobose in outline, with durable and aromatic wood, watery sap, 

 and a furrowed resinous bark. Pith in plates. Leaflets conduplicate in vernation : 

 blades membranous. Staminate aments solitary, simple, arising from the branchlets 

 of the preceding year, drooping: calyx 3-6-lobed. stamens in several rows: anthers 

 glabrous, each surmounted by a conspicuous connective. Pistillate flowers solitary 

 or several in terminal spike-like clusters on the twigs of the present year: sepals 

 adnate to the ovary: ovary inferior: stigmas plumose, spreading. Fruit globose or 

 oblong-cylindric, sometimes obscurely angled: husk indehiscent, glabrous or glandular- 

 hirsute: nut deeply sculptured, thick-walled. Seed with 2-lobed cotyledons. The plants 

 flower in the spring and mature their fruit in the fall. Walnut. 



Anther-connective a rounded lip: fruit elongated, viscid -pubescent: nut 4-angled. 1. J. cineria. 

 Anther-connective crown-like: fruit not elongated, glabrous: nut not angled. 



Leaflets with lanceolate of narrowly lanceolate blades: fruits 5-8 cm. i diameter. 2. J . nigra. 



Leaflets with ovate or ovate-lanceolate blades: fruits 2-3 cm. in diameter. 3. J. rupesiris. 



1. Juglans cinferea L. Tree becoming 30 m. tall, the heartwood pale : leaflets 



11-17, the blades lanceolate to oblong-lanceolate or oblong, 6-12 cm. long: staminate 



aments 6-15 cm. long: fruits 8-12 cm. long, usually acute: nut 2-celled below the 



middle, the ridges thin and brittle. 



In moist soil and woods, New Brunswick to North Dakota, Georgia and Arkansas. 

 Bdtteenut. White Walnut, 



2. Juglans nigra L. Tree becoming 50 m. tall, the heart-wood dark brown: 

 leaflets 15-23, the blades 8-10 cm. long, rounded or subcordate at the base: stami- 

 nate aments 5-10 cm. long: fruits 5-8 cm. in diameter: nut 4-celled below the 

 middle, sculptured, the ridges thick firm. 



In rich soil, Massachusetts to Ontario, Minnesota, Florida and Texas. Black Walnut. 



3. Juglans rup^stris Engelm. Tree becoming 16 m. tall, the heart-wood dark 

 brown: leaflets 9-23, the blades narrowed at the base: staminate aments 5-10 cm. 

 long: fruits 2-3 cm. in diameter, the nut 4-celled below the middle, longitudinally 

 grooved, the ridges thick. 



In valleys, Texas, New Mexico and Mexico. 



2. HICORIA Raf. 

 Trees, cylindric in outline, with hard and very tough wood, a watery sap, and a 

 close or scaly bark. Pith solid. Leaflets involute in vernation: blades usually 

 leathery. Staminate aments often branched, clustered on the twigs of the preceding 

 year or at the base of the twigs of the present year, mostly long-stalked: calyx 3-lobed: 

 stamens 3-10, in several rows: anthers 2-celled, pubescent, each notched at the apex; 

 sacs opening lengthwise, with an inconspicuous connective. Pistillate flowers in spike- 

 like clusters at the ends of the twigs of the present year: calyx of 1 sepal adnate on 

 the ovary: ovary inferior: stigmas spreading. Fruit subglobose, obovoid or cylindric: 

 husk becoming dry, 4-valved, splitting more or less readily to the middle or base, its 

 angles sometimes winged: nut smooth, thin-walled or thick-walled, more or less 



