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7. Trema Loureiro, Fl. Cochinch. 2: 539, 562. 1790.
山黄麻属 shan huang ma shu
Trees or large shrubs, evergreen. Branchlets never spinose, never corky or winged. Stipules 2, free, caducous, leaving a short transverse scar on each side of leaf base. Leaves alternate in several ranks; leaf blade ovate to narrowly lanceolate, margin denticulate; usually 3(-5)-veined from base (venation pinnate in T. levigata); secondary veins anastomosing before reaching margin. Inflorescences subsessile. Flowers unisexual or polygamous, shortly pedicellate. Male flowers: (4 or)5-lobed; tepals incurved, valvate, or ± imbricate. Stamens equal in number to tepals. Ovary rudimentary, basally with perigynous pubescence. Female flowers: (4 or)5-lobed. Ovary sessile, basally with perigynous pubescence. Drupes 1.5-5 mm in diam., erect, elliptic to ± globose; tepals and stigmas persistent or rarely perianth caducous; exocarp ± fleshy, endocarp bony. Endosperm fleshy; embryo curved or involute; cotyledons narrow.
About 15 species: tropical and subtropical areas; six species (two endemic) in China.
Trema species are often found in E and SW China, particularly in disturbed and degraded habitats.
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| 1 |
Leaf blade abaxially glabrous except for appressed hairs on major veins. |
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(2) |
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Leaf blade abaxially pubescent over its whole surface. |
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(3) |
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| 2 (1) |
Perianth caducous in fruit; leaf blade elliptic-lanceolate to narrowly lanceolate, rarely 3-veined from base. |
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1 T. levigata |
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Perianth persistent in fruit; leaf blade ovate, ovate-oblong, or rarely lanceolate (in T. cannabina var. cannabina), strongly 3-veined from base. |
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6 T. cannabina |
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| 3 (1) |
Leaf blade 3-7 × 1-2 cm, abaxially densely white-tomentose, with inconspicuous rust-colored glandular hairs on veins, adaxially very scabrous; petiole 2-5 mm; male flower tepals densely hirsute inside. |
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5 T. angustifolia |
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Leaf blade (5-)7-22 × 1.5-9(-11) cm, adaxially ± smooth to ± scabrous, without rust-colored glandular hairs on veins; petiole 4-20 mm; male flower tepals not hirsute inside. |
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(4) |
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| 4 (3) |
Leaf blade abaxially sparsely pubescent, usually with crowded minute dark red sessile glands; petiole 4-8 mm (in T. cannabina var. dielsiana). |
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6 T. cannabina |
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Leaf blade abaxially densely pubescent, not glandular; petiole 7-20 mm. |
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(5) |
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| 5 (4) |
Leaf blade lanceolate to narrowly lanceolate, 1.5-4.5 cm wide; inflorescences shorter than petiole. |
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4 T. nitida |
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Leaf blade ovate, ovate-oblong, or rarely broadly lanceolate, 3-9(-11) cm wide; inflorescences as long as or longer than petiole. |
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(6) |
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| 6 (5) |
Plant to 10 m tall; fruit rounded-ovoid, 2-3 mm in diam.; leaf blade ± concolor, abaxially with grayish brown pubescence, surface of blade visible between hairs under magnification, adaxially very scabrous with erect bristles. |
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2 T. tomentosa |
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Plant to 20 m tall; fruit ovoid-globose to ± globose, 3-5 mm in diam.; leaf blade grayish white to grayish green abaxially much paler than adaxially and pubescent, surface completely hidden by hairs, adaxially ± scabrous and usually rugate. |
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3 T. orientalis |
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Lower Taxa
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