Endemic to South central Madagascar, Mangoky and Onilahy river systems.
In shallow standing water on riverbanks, swampy valley bottoms, either in deciduous forest or in gallery forest; alt. 350-750 m; gregarious, often forming stands. TRUNK 5-22 m high, cylindrical or slightly inflated towards the middle, 36-50 cm in diam., near crown 15-18 cm in diam.; internodes 4-10 cm; wood with tough black fibre layer in the outer part; inner wood soft; bark pale brown-grey ; diameter of base of crown about 22 cm. LEAVES 16-25 in the crown, porrect to pendulous, slightly arching, held on edge in the distal half of the leaf; sheath 30-50 x 15-16 cm, green and proximally with cottony white or grey-brown indument; margins ragged and fibrous; petiole 6-20 cm long, 4-4.5 x 1.5-1.6 cm across, adaxially flat with slightly sharp edges, white-waxy and -scaly; rachis green, white and scaly when young, 1.2-1.7 m long, 1-1.7 cm wide towards the middle, abaxially almost flat or slightly convex, densely pubescent to glabrescent, adaxially flat in the proximal half, more distally keeled with flat top and with the keel almost as wide as the rachis; leaflets regular, in one plane, stiff to pendulous, attenuate, green to slightly yellow, slightly waxy, 70-73 on each side of the rachis, the proximal 20-55 x 0.5-1.7 cm, the median 52-64 x 1.5-3.2 cm (interval about 2 cm), the distal 16-42 x 0.4-1.9 cm, especially abaxially with the veins bearing minute whitish scales, also with a few large brown or grey ramenta on midrib abaxially.