ANGIOSPERM FAMILIES 02

JUGLANDACEAETHE WALNUT FAMILY

JUGLANDACEAETHE 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 FLOWERSJUGLAND NIGRA L. JUGLANS CINEREA L.

JUGLANS MALE FLOWERSJUGLANS 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 COMPARISONJUGLANS 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; 3 -17 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.) NuttMockernut hickory.

LEAF FRUITS

CARYA TOMENTOSA (Poir.) Nutt.

CARYA GLABRA (Mill.) SweetPIGNUT HICKORY

LEAF FRUIT

CARYA GLABRA (Mill.) SweetPIGNUT HICKORY

TWIG LEAF UNDERSIDE

CARYA ILLINOIENSIS (Wangen.) K. KochPECAN

CARYA ILLINOIENSIS (Wangen.) K. KochPECAN

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.