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Key to families | Table of families and genera

This text currently parallels The Jepson Manual: Vascular Plants of California, Second Edition that is now available at the University of California Press.

Text appearing in blue on this page will not appear in the printed book; it will be displayed only on the Web. Specimen numbers are hyperlinked to records in the Consortium of California Herbaria data view where possible. Taxa are hyperlinked to entries in the Jepson Interchange via the "[Online Interchange]" link.

 

JUGLANDACEAE WALNUT FAMILY

Alan T. Whittemore


Shrub, tree; monoecious.
Leaf: odd-(even-)1- pinnate, alternate, deciduous; stipules 0.
Inflorescence: catkin, generally appearing before leaves, 1 or clustered; flowers generally 1 in bract axils.
Staminate inflorescence: pendent, elongate, many-flowered, on last yr's twigs.
Pistillate inflorescence: erect; flowers 1–many, at tip of new twigs.
Staminate flower: calyx [0 or] lobes generally 4 [2, 6]; petals 0; stamens 3–40[50]; pistil 0 or vestigial.
Pistillate flower: calyx [0] or lobes 4; petals 0; stamens 0; ovary 1, inferior, chamber 1 above, generally 2 below, styles 2, plumose.
Fruit: nut enclosed in husk or winged nutlets.
9 genera, > 60 species: n temperate, subtropical mountains; some ornamental, cultivated for wood, nuts (Carya hickory, pecan; Juglans walnut). [Stone 1997 FNANM 3:416–428] In Carya, Juglans, husk included in fruit diam, even though derived from involucre, calyx, and therefore not technically part of fruit. —Scientific Editor: Thomas J. Rosatti.
Unabridged references: [Elias 1972 J Arnold Arbor 53: 26–51]

Key to Juglandaceae

1. Infl pendent in fruit, of 15–50 2-winged nutlets, not enclosed in husk; fruit body (except wings) 6–9 mm diam; main axis of leaf ± winged (at least below leaflet attachment distally) ..... [Pterocarya stenoptera]

1' Infl erect in fruit, of 1–3 unwinged nuts, enclosed in leathery husk, fruit (including husk) 2–5 cm diam; main axis of leaf not winged

2. Twig centers not chambered; staminate inflorescences clustered, ± sessile, stamens 3–10(15) per flower; fruit husk splitting longitudinally, separating from fruit ..... CARYA

2' Twig centers chambered; staminate inflorescence solitary, sessile, stamens 15–40 per flower; fruit husk not splitting, not separating from fruit ..... JUGLANS

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