14. Arenga Labillardière, Bull. Sci. Soc. Philom. Paris. 2: 162. 1800.
桄榔属 guang lang shu
Blancoa Blume (1843), not Lindley (1840); Didymosperma H. Wendland & Drude; Gomutus Corrêa; Saguerus Steck.
Understory shrubs to large trees. Stems clustered, sometimes spreading by stolons, less often solitary, usually covered with persistent, fibrous leaf bases. Leaves 5-30, pinnate, seldom undivided; leaf sheaths open, fibrous, commonly persisting on stems; petioles usually covered with distinctive scales; pinnae linear to rhomboid, sometimes lobed on margins, always jagged at apices, bases sometimes with an ear-shaped projection overlapping rachis; pinnae regularly or irregularly arranged, basal few borne in clusters, silvery gray abaxially. Plants usually semelparous; flowering proceeding from top of stem downward (basipetal), rarely in opposite direction (acropetal). Inflorescences branched to 2 orders, rarely spicate, borne among leaves, usually unisexual by suppression of either female or male flowers, solitary or rarely several at a node, covered with several persistent bracts, female inflorescences commonly produced first at apex of stem, and male ones later, below; rachillae 1-100 or more; flowers borne in triads with a central female flower and 2 lateral male flowers. Fruits red, yellowish, or purplish, large, ellipsoid, globose, ovoid, or oblong, 1-3-seeded; mesocarp with irritant crystals of calcium oxalate; endosperm homogeneous; germination remote; eophylls undivided or bifid with jagged margins.
Twenty-one species: from India through SE Asia reaching to New Guinea and Australia; six species (two endemic, one introduced) in China.