Areca
Moderate sized, solitary or clustering, monoecious palms. Stem often with green internodes, distinct leaf scars distally, and a cone of adventitious roots basally. Leaves 5–10 in crown, spirally arranged; sheath tubular forming a yellowish to brownish tinged green crownshaft; petiole very short or less than 50 cm long, unarmed, smooth; blade splitting in usually regularly distributed, one to several folded, narrowly sigmoid pinnae, distributed in one plane, leaf apex often composed of several irregularly splitting, closely inserted pinnae. Inflorescence infrafoliar, branched from 1. to 3. order, sheathed in bud only by the prophyll, this thinly coriaceous and early deciduous, peduncle short, inflorescence branches spreading to stiffly erect. Unisexual flowers in cymose paracladia of two to three, or solitary towards the rachillae apices, female flowers much larger than male flowers only fully developed at the very base of the rachillae, male flowering part of rachillae wilting and often present as tails in the infructescence. Fruit one seeded, epicarp smooth usually red at maturity, mesocarp usually thin, fleshy to fibrous, endocarp composed of longitunal fibres, more or less free at the base, endosperm deeply ruminate.
Fifty species found in tropical and subtropical Asia; four species native in Thailand, one (A. catechu) is only known from cultivation and not included here since it has not been recorded from the wild (Plate XCVIII.A).