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21. Pentapanax Seemann, J. Bot. 2: 290, 294. 1864.
羽叶参属 yu ye shen shu
Aralia sect. Pentapanax (Seemann) J. Wen; Hunaniopanax C. J. Qi & T. R. Cao; Parapentapanax Hutchinson.
Trees or shrubs, evergreen or deciduous, sometimes epiphytic, hermaphroditic or andromonoecious, unarmed. Leaves pinnately compound, rarely simple; leaflets entire to serrate; stipules absent. Inflorescence a terminal panicle of umbels, heads, or racemules, glabrous or pubescent, developing from specialized floral buds, usually surrounded by numerous persistent bracts at base. Pedicels articulate below ovary. Calyx minutely 5-dentate. Petals 5(-7), imbricate. Stamens 5(-7). Ovary (3-)5(-7)-carpellate; styles united into a column or divided, as many as carpels. Fruit a drupe, globose to ellipsoid or ovoid. Seeds as many as carpels; endosperm uniform.
Between 18 and 22 species: restricted to Asia, especially the Sino-Himalayan region; 16 species (nine endemic) in China.
The first author finds it hard to accept Wen’s point of view (see following paragraph), in which Pentapanax was treated as a section of the genus Aralia, and instead recognizes Pentapanax as distinct from Aralia on the basis of three main morphological differences: (1) inflorescences developing from specialized floral buds that are usually surrounded at the base by numerous persistent bracts (vs. from mixed buds, not surrounded by bracts at the base); (2) plants woody and unarmed (vs. woody and usually prickly, or herbaceous); and (3) leaves 1(-3)-pinnate (vs. leaves usually 2-4-pinnate). Several phylogenetic studies have shown, however, that Pentapanax forms a group that is clearly nested within Aralia (Wen, Brittonia 45: 47-55. 1993; Wen, Edinburgh J. Bot. 58: 183-200. 2001; Wen et al., Acta Bot. Yunnan. 24: 557-568. 2002). The most recent revision (Wen, Cathaya 13-14: 1-116. 2002) treated the members of this group as a section within Aralia, an interpretation favored by the second author.
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| 1 |
Evergreen trees; ultimate inflorescence units racemose |
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(2) |
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Deciduous shrubs, small trees, or herbs; ultimate inflorescence units umbellate or capitulate |
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(3) |
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| 2 (1) |
Inflorescence glabrous; pedicels 2-3 mm; styles mostly united into a column. |
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1 P. subcordatus |
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Inflorescence ± pilose; pedicels 0.5-1.5 mm; styles free to united to middle. |
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2 P. racemosus |
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| 3 (1) |
Leaflets entire or finely serrulate at margin |
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(4) |
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Leaflets serrate at margin (except in |
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13b P. fragrans var. forrestii). |
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| 4 (3) |
Leaves simple, abaxially glaucous. |
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3 P. hypoglaucus |
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Leaves pinnately compound, leaflets 3-5 |
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(5) |
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| 5 (4) |
Ovary 3(-5)-carpellate; styles free at apex only. |
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4 P. glabrifoliolatus |
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Ovary 5-carpellate; styles united into a column |
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(6) |
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| 6 (5) |
Inflorescence a terminal umbel or small panicle of umbels with distinct peduncles. |
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5 P. parasiticus |
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Inflorescence with 1-3 verticils of flowers along primary axis. |
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6 P. verticillatus |
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| 7 |
Leaves 2- or 3-pinnately compound |
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(8) |
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Leaves 1-pinnately compound or trifoliolate |
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(10) |
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| 8 (7) |
Leaves 2- or 3-pinnately compound, often with accessory pinnae, leaflets often abaxially densely white tomentose. |
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15 P. plumosus |
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Leaves mostly 2-pinnately compound, without accessory pinnae, leaflets abaxially glabrous |
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(9) |
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| 9 (8) |
Leaflets ovate or suborbicular, 3-6 × 4-6.5 cm, apex acute; peduncle 2-4 cm. |
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12 P. caesius |
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Leaflets ovate-oblong or ovate-lanceolate, 1.5-3 × 0.5-3.5 cm, apex acuminate; peduncle 3-6 cm. |
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16 P. wilsonii |
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| 10 (7) |
Inflorescence without a distinct primary axis, or primary axis less than 2 cm |
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(11) |
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Inflorescence with a distinct primary axis 5-50 cm |
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(12) |
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| 11 (10) |
Secondary axes of inflorescence with a terminal umbel and 2-6 lateral verticellately arranged umbels. |
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13 P. fragrans |
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Secondary axes of inflorescence with a single terminal umbel. |
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14 P. longipedunculatus |
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| 12 (10) |
Styles free or united basally, free, reflexed apically |
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(13) |
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Styles united into a column, sometimes divided at their apices |
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(15) |
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| 13 (12) |
Inflorescence and leaflets pubescent; leaflets (3-)5; styles connate at base, free apically. |
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11 P. tomentellus |
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Inflorescence and leaflets glabrous; leaflets 5-7; styles free, reflexed |
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(14) |
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| 14 (13) |
Leaflets ovate to suborbicular, subleathery, apex acute, margin serrulate. |
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12 P. caesius |
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Leaflets ovate-elliptic, membranous, apex acuminate, margin irregularly serrate. |
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7 P. yunnanensis |
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| 15 (12) |
Inflorescence and leaflets glabrous |
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(16) |
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Inflorescence densely pubescent; secondary veins more than 8 pairs |
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(17) |
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| 16 (15) |
Leaflets (3-)5, margins serrate. |
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7 P. yunnanensis |
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Leaflets 3, margins ciliate. |
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8 P. longipes |
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| 17 (15) |
Leaflets 3-5, 7-20 × 4-11 cm. |
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9 P. henryi |
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Leaflets 5-7, 6-9 × 2.5-4 cm. |
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10 P. castanopsidicola |
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List of lower taxa
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