Calamus maturbongsii, an Unusual New Rattan Species from New Guinea

Abstract

Summary. An unusual species of rattan from New Guinea, Calamus maturbongsii (Calamoideae Arecaceae), is described as new. Although some superficial similarities to other New Guinea rattan species and the West Malesian Calamus section Platyspathus are noted, the extraordinary morphology and expansion mechanism of the inflorescence together with peculiar vegetative features indicate that C. maturbongsii is a striking new species of uncertain affinities. During the course of research for the Palms of New Guinea Project, we have encountered many surprising new species, but the rattan described herein must count as one of the most extraordinary of all. Calamus maturbongsii W J. Baker J isotypus MAN). Moderately robust, clustering rattan climbing to 30 m. Stem with sheaths 16 - 22 mm diam., without sheaths to 10 - 11 mm diam.; internodes c. 48 cm. Leafecirrate, to 1 m long including petiole; sheaths with very thin, white, cobweb-like indumentum, unarmed or armed with very few, scattered, minute, easily detached, triangular spines to 1 mm; knee 13 - 22 x 16 - 21 mm, unarmed, with conspicuous ridge at the base, both ends of ridge somewhat deflexed; ocrea 3 - 5 mm, forming a low collar almost entirely encircling stem, persistent, drying woody, brittle, unarmed; flagellum to 1.7 m, with numerous grapnel spines arranged subregularly to irregularly; petiole 3 - 5 mm long, 6 - 11 x 3 - 6 mm at base, flat adaxially, rounded abaxially, unarmed; rachis with grapnel spines arranged subregularly, abaxial surface with indumentum as sheath, adaxial surface with numerous dark purple-brown scales; leaflets 7 - 12 each side of rachis, arranged regularly, lanceolate with cucullate apices, longest leaflet near leaf base 26 - 36 x 4.5 - 5 cm, the basal pair of leaflets almost as large as longest leaflets, mid-leaf leaflets 24.5 - 26 x 4.3 - 5.5 cm, apical leaflets 5.5 - 12 x 0.7 - 2 cm, apical leaflet pair not united or united to one quarter of their length, leaflets glabrous and unarmed or with exceedingly few bristles on margin or tip, transverse veinlets conspicuous. Staminate