Juglandaceae: Walnut Family


Description of the Family:

Habit: monoecious trees

Leaves***: alternate, ***pinnately compound, estipulate; ***with peltate, aromatic glands

Flowers: small, unisexual; staminate inflorescences are catkins; pistillate inflorescences a solitary flower (rarely catkins)

Sepals: 4 and connate in staminate flowers (4 connate and adnate to the ovary in pistillate flowers)

Petals: absent

Stamens: 5-40, distinct

Gynoecium***: of 2-3 connate carpels; ovary inferior*** with 1 locule and 1 basal ovule

Fruit***: nut (or drupe, sometimes winged with adnate bracts); ***When a nut often surrounded by bracts that subtend the flower that mature to form a husk.....; nut inside is fruit that splits in 2 halves along midveins of carpels; seeds large with no endosperm and massive sculptured cotyledons

Diverstiy: 8 genera / 60 species

Distribution: mostly north-temperate

Economics edible nuts, wood very important in 18th century "the foremost cabinet wood of N Am." All large hickories cut....in 18th-19th century; also walnut oil -- hardens but does not become rancid; excellent preservative for cutting boards, ect....

Juglans (walnut) -- chambered pith in twigs

Carya (hickory) -- pith not chambered (genus of pecan)


Representative species found in Arizona:

Carya illinoinensis

Juglans major

Urtica sp.


Home  |  Tree  |  Map  |  Quiz