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FOC | Family List | FOC Vol. 16 | Apocynaceae

9. Alstonia R. Brown, Mem. Wern. Nat. Hist. Soc. 1: 75. 1811.
[nom. cons.]

鸡骨常山属 ji gu chang shan shu

Blaberopus A. de Candolle; Winchia A. de Candolle.

Trees or shrubs, latex present. Branches whorled, mostly 4 or 5 together. Leaves whorled, rarely opposite; lateral veins numerous, ending in a marginal vein. Cymes terminal, usually 1-5 in thyrses or compound umbels, terminal. Flowers white, yellow, or pink. Calyx without glands inside, lobes connate at base. Corolla salverform, tube cylindric, dilated in distal half, pubescent inside, lobes overlapping to right or left. Stamens included, inserted near or above middle of corolla tube; anthers ovate, free from pistil head, not caudate; disc absent or of scales. Ovaries 2, distinct or connate, ovules numerous. Follicles 2, free or connate. Seeds oblong or linear, long bearded at both ends; endosperm thin; cotyledons up to twice as long as radicle.

About 60 species: tropical Asia, Africa, C America, N Australia, Pacific Islands; eight species in China.

1 Trees; disc absent or small annular.   (2)
+ Shrubs; disc of 2 scales alternating with ovaries.   (4)
2 (1) Lateral leaf veins widely spaced, (3-)5-12 mm apart, ascending; corolla lobes in bud overlapping to right; seeds acuminate at 1 end   2 Alstonia macrophylla
+ Lateral leaf veins close together, 1-6 mm apart, horizontal or almost so; corolla lobes in bud overlapping to left; seeds obtuse or rounded at both ends.   (3)
3 (2) Leaf apex long acuminate; ovary syncarpous; follicles solitary   1 Alstonia rostrata
+ Leaf apex rounded to short acuminate; ovary of 2 separate carpels; follicles paired   3 Alstonia scholaris
4 (1) Leaves sessile, blade thick, papery to ± leathery, lateral veins at almost 90° to midvein.   (5)
+ Leaves petiolate, blade thin, membranous, lateral veins at 45° to midvein.   (6)
5 (4) Leaves pubescent abaxially; corolla to 3 cm   5 Alstonia neriifolia
+ Leaves glabrous abaxially; corolla ca. 1.1 cm   6 Alstonia rupestris
6 (4) Leaves pubescent on both surfaces; corolla pink to red   4 Alstonia yunnanensis
+ Leaves glabrous; corolla white or yellow.   (7)
7 (6) Colleters few and inconspicuous; corolla white, to 3 cm, tube 1-2 cm; disc lower than ovary   7 Alstonia mairei
+ Colleters numerous, becoming ± indurated at base and persisting; corolla yellow, ca. 1 cm; tube ca. 0.8 cm; disc as long as ovary   8 Alstonia henryi

Lower Taxa


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