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Key to families | Table of families and genera

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 year'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: northern 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. Inflorescence 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' Inflorescence 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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Citation for the whole project: Jepson Flora Project (eds.) [year] Jepson eFlora, http://ucjeps.berkeley.edu/IJM.html [accessed on month, day, year]
Citation for an individual treatment: [Author of taxon treatment] [year]. [Taxon name] in Jepson Flora Project (eds.) Jepson eFlora, [URL for treatment]. Accessed on [month, day, year].
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