Medemia Wurttenb. ex H.Wendl., Bot. Zeitung (Berlin) 39: 89 (1881)

Primary tabs

Diagnosis

Biology And Ecology

Uses

Description

  • Robust, solitary, unarmed, pleonanthic, dioecious, tree palm. Stem erect, ringed with close leaf scars. Leaves induplicately costapalmate, marcescent, or falling under their own weight; sheath soon becoming open, densely tomentose, later with a conspicuous triangular cleft below the petiole, margins fibrous; petiole well developed, flattened adaxially, rounded abaxially, the margins armed with widely spaced coarse, forward-pointing spines, mostly in the mid-section; hastulae absent; costa short, more conspicuous abaxially than adaxially; blade divided ± regularly along adaxial folds to ca. 2/3 its length into single-fold segments, these further divided for a very short distance along abaxial folds, interfold filaments persistent at the adaxial sinuses, surfaces ± glaucous, with scattered dot-like scales, particularly along the ribs on the abaxial surface, longitudinal veins crowded, transverse veinlets obscure. Inflorescences interfoliar, becoming pendulous; prophyll and peduncular bracts, if any, not seen; rachis bracts tubular, with scattered caducous scales, and a long triangular limb; first-order branches ± pendulous, devoid of bracts except at the tip, margins sharp, the surfaces bearing scattered caducous scales, staminate inflorescence with first-order branches bearing at their tips 1–7 digitately displayed rachillae, in the pistillate bearing a single rachilla; rachillae catkin-like, bearing a tight spiral of rounded, densely hairy, imbricate bracts, connate laterally and to the axis to produce pits, filled with a dense pile of hairs. Staminate flowers borne in threes, each bearing a spathulate membranous bracteole included within the pit, the flowers exserted and exposed one by one from the pit; calyx stalk-like at the base with 3 narrow, spathulate, membranous, striate lobes with irregular margins; corolla with a conspicuous stalk-like base almost as long as the calyx lobes, bearing at its tip 3 oblong, membranous, striate, ±circular lobes; stamens 6, borne at the base of the corolla lobes, filaments elongate, tapering, anthers medifixed, apparently versatile, latrorse; pistillode 3-lobed, small. Pollen ellipsoidal, slightly asymmetric; aperture a distal sulcus; ectexine tectate, coarsely perforate-rugulate, aperture margin slightly finer; infratectum columellate; longest axis 36–49 µm [1/1]. Pistillate flowers solitary, borne on a short, densely hairy pedicel, lengthening after fertilisation; sepals 3, distinct, imbricate, obtuse, broad, membranous, glabrous, striate; petals 3, similar to the sepals; ?staminodes; gynoecium globose, with 3 eccentric, short, recurved stigmas, ovule probably orthotropous. Fruit ovoid, borne on the elongated pedicel, usually developed from only 1 carpel, rarely from 2 and then bilobed, with basal stigmatic remains, perianth whorls persistent; epicarp smooth, shiny, marked with scattered lenticels, mesocarp moderate, apparently ± dry at maturity, with ± radiating short fibres embedded in soft parenchyma, endocarp rather thin, crustaceous. Seed basally attached, ± broad, ellipsoidal, endosperm with a central hollow, conspicuously ruminate, the ruminations radial; embryo apical. Germination remote-tubular; eophyll entire, lanceolate. Cytology not studied. (J. Dransfield & N. Uhl & C. Asmussen & W.J. Baker & M. Harley & C. Lewis, Genera Palmarum. The evolution and classification of palms. 2008)

Fossil record

Relationships

Bibliography

A. J. Dransfield & N. Uhl & C. Asmussen & W.J. Baker & M. Harley & C. Lewis, Genera Palmarum. The evolution and classification of palms. 2008
B. World Checklist of Arecaceae