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4. Torreya Arnott, Ann. Nat. Hist. 1: 130. 1838.
[nom. cons.]
榧树属 fei shu shu
Trees evergreen, dioecious (occasionally monoecious); branches whorled; branchlets subopposite or subwhorled, base with bud scales not persistent; winter buds with several pairs of decussate bud scales. Leaves decussate or subopposite, 2-ranked, linear or linear-lanceolate, basally twisted, leathery, adaxial surface slightly convex with midvein ± indistinct, abaxial surface with 2 stomatal bands, resin canal present on abaxial side of vascular bundle, base decurrent, apex sharply acuminate. Pollen cones axillary, solitary, shortly pedunculate, ellipsoid or shortly columnar; microsporophylls in 4-8 whorls each of 4 microsporophylls; pollen sacs (3 or)4, marginal, pendulous. Seed-bearing structures borne in pairs in leaf axils, sessile, each with 2 pairs of decussate bracts and 1 lateral bract; ovule 1, erect. Aril succulent, base of aril with persistent bracts. Seed ripening in autumn of 2nd year, drupelike, completely enclosed within aril; female gametophyte tissue ruminate or not. Cotyledons 2. Germination hypogeal. 2n = 22.
Six species: China, Japan; SE and W United States; four species (three endemic, one introduced) in China.
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1 |
Leaves borne at 20-60° to branchlet axis, 3.5-9 cm, stomatal bands silvery gray initially, later turning brown |
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4 Torreya jackii |
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Leaves usually borne at 60-90° to branchlet axis, (0.7-)1.1-3.6(-4) cm, stomatal bands brown even when young. |
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(2) |
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2 (1) |
Leaves with 2 longitudinal grooves adaxially, midvein distinctly narrower than marginal bands |
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3 Torreya fargesii |
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Leaves without 2 longitudinal grooves adaxially, midvein about as wide as marginal bands. |
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(3) |
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3 (2) |
Leaves (0.7-)1.1-2.5(-4.5) cm, base obtuse or broadly rounded, apex cuspidate; axis of 2nd- or 3rd-year branchlets yellowish green, light brownish yellow or pale brown |
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2 Torreya grandis |
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Leaves 2-3 cm, base slightly rounded or cuneate, apex very long acuminate; axis of 2nd- or 3rd-year branchlets green or reddish brown |
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1 Torreya nucifera |
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Lower Taxa
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