ANGIOSPERM FAMILIES 02 JUGLANDACEAE THE WALNUT FAMILY

JUGLANDACEAE THE WALNUT FAMILY Trees or large shrubs. Forests of the North Temperate zone and to some extent in the tropics of both hemispheres. 9 genera and about 60 species worldwide. Two genera and 17 species in N America. – Juglans – Carya

CHARACTERISTICS OF THE FAMILY HABIT: trees and large shrubs. LEAVES: deciduous, alternate, pinnately compound, estipulate. FRUIT: a hard nut surrounded by woody or semifleshy husk; husk dehiscent or indehiscent; seed with large convoluted cotyledons.

DETAILS OF THE FLOWER Anemophilous. Unisexual, monoecious. Calyx lobed, 3-5 lobes; subtended by a bract and two bracteoles. Petals absent. Staminate flowers in catkins. Pistillate flowers solitary or few in stalks.

JUGLANS FEMALE FLOWERS JUGLAND NIGRA L.JUGLANS CINEREA L.

JUGLANS MALE FLOWERS JUGLANS NIGRA L.JUGANS CINEREA L.

GENUS JUGLANS LEAVES: pinnate, odd or even pinna number; leaflets 9-23, sessile or nearly so, oblong- lanceolate, apex acute or acuminate, uneven base, margin finely serrate, apical leaflet often absent; petiole and rachis stout and finely pubescent. FLOWER: plant monoecious; imperfect; male flowers in catkins; female flower solitary or in short spikes, with plumose stigmas.

GENUS JUGLANS cont. FRUIT: a nut with semifleshy indehiscent husk; nut thick-walled, corrugated; seed sweet often oily. TWIGS: light brown, stout, pubescent or glabrous; pith chambered; terminal bud with few scales. LEAF SCARS: 3-lobed, with three U-shaped bundle scars.

JUGLANS NIGRA L. Black walnut

JUGLANS CINEREA L. Butternut or White walnut

FRUIT COMPARISON JUGLANS NIGRA L.JUGLANS CINEREA L.

GENUS JUGLANS Range in North America Juglans nigra L.Juglans cinerea L.

GENUS CARYA Nutt. HICKORIES Trees Present range: Eastern North America, southern Canada and Mexico; Caucasus to Japan. Extinct range: Europe, N Africa, Asia, and N America. 18 extant species; several extinct species.

CHARACTERISTICS OF THE GENUS LEAVES: pinnately compound; sessile or nearly so leaflets, apical leaflet usually the largest; leaflets ovate to obovate, apex acute or acuminate, uneven bases, margin finely serrate, pubescent; petiole and rachis pubescent or glabrous, stout. FLOWERS: plant monoecious, flowers imperfect; staminate flowers in 3-branched catkins, 3 to 7 stamens, 2-3 lobed calyx;

CHARACTERISTICS OF THE GENUS FLOWERS cont.: pistillate flowers on 2 to 10 terminal spikes, ovary 1-celled with two stigmas, subtended by a bract and three bracteoles. FRUIT: ovoid, pyriform or globose nut encased in a woody husk that may split in four sutures; seed with a thick or thin shell. TWIG: stout or slender, dark brown, gray or orange brown; terminal bud large

CHARACTERISTICS OF THE GENUS SCARS: 3-lobed or deltoid; many bundle scars in 3 U-shaped clusters. PITH: homogeneous NORTH AMERICAN HICKORIES are grouped in two sections: – Section Carya, true hickories – Section Apocarya, pecan hickories

INFRAGENERIC CLASSIFICATION SECTION Carya, true hickories – Leaflets 5 – 7, terminal leaflet the largest. – Fruit unwinged, with sutures occasionally ribbed. – Bud scales imbricate; 6 – 9 thin scales SECTION Apocarya, pecan hickories – Leaflets 7 – 13, leaflets similar. – Fruit broadly winged at the sutures. – Bud scales not overlapping; 4 – 6 fleshy scales.

CARYA TOMENTOSA (Poir.) Nutt Mockernut hickory. LEAFFRUITS

CARYA TOMENTOSA (Poir.) Nutt.

CARYA GLABRA (Mill.) Sweet PIGNUT HICKORY LEAFFRUIT

CARYA GLABRA (Mill.) Sweet PIGNUT HICKORY TWIGLEAF UNDERSIDE

CARYA ILLINOIENSIS (Wangen.) K. Koch PECAN

ECONOMIC IMPORTANCE OF THE JUGLANDACEAE The walnuts produce a valuable wood used in cabinetry. Hickories produce a very strong wood used for many purposes where strength is needed. Pecan is the most valuable nut in N America. The nuts of walnuts and hickories are an important source of food for wildlife. Important ornamental trees.