Dictyosperma H.Wendl. & Drude, Linnaea 39: 181 (1875)

Primary tabs

Diagnosis

Biology And Ecology

Etymology

Uses

Description

  • Stout, solitary, unarmed, pleonanthic, monoecious palm. Stem erect, sometimes enlarged at the base, brown or grey, often vertically fissured. Leaves pinnate, spreading with arched, ±pendulous leaflets; sheath tubular, forming a prominent crownshaft, thinly to densely white, grey or brown tomentose; petiole very short, nearly flat to slightly rounded adaxially, abaxially rounded, tomentose marginally and adaxially, the scales with blackish centres and pale, tattered-twisted margins, deciduous, leaving dot-like scars; rachis adaxially angled with scales as on the petiole, abaxially rounded; leaflets lanceolate, acute, single-fold, subopposite, regularly arranged, abaxially with pale to dark brown, twisted, basifixed or medifixed membranous ramenta on the midrib, midrib conspicuous adaxially, transverse veinlets not evident. Inflorescences infrafoliar, protandrous, as many as 6 present below the crownshaft, erect in bud, branched to 1 order, branches stiff, ascending, ± unilateral; peduncle very short, dorsiventrally compressed, grey-brown tomentose; prophyll tubular, bluntly pointed, rather wide, shortly 2-keeled laterally, glabrous or with deciduous grey tomentum, splitting adaxially, caducous; peduncular bract like the prophyll, lacking keels, beaked, rather thin, fibrous; rachis longer than the peduncle, stout, tapering, ± densely covered with twisted hairs or glabrous, bearing acute or low rounded bracts subtending rachillae on 3 sides, lacking rachillae adaxially, at least toward the base; rachillae moderate, tapering, stiff, ascending, becoming recurved, glabrous or hairy only at the base, bearing triads in the lower 1/2–4/5, and paired staminate flowers distally; floral bracteoles low, flattened, not sepal-like. Staminate flowers sessile or briefly pedicellate, yellow to maroon, asymmetrical; sepals 3, distinct, slightly imbricate at the base only, acute, keeled and ± gibbous towards the base; petals 3, distinct, valvate, ovate, acute, with an outer layer of thick fibres and tannin cells; stamens 6, filaments stout, inflexed at the apex in bud, anthers dorsifixed near the middle, becoming versatile, linear-lanceolate, briefly bifid at the apex, more deeply bifid basally, the locules in bud separated by a very narrow sterile portion, latrorse; pistillode nearly as long as the stamens, tapered to a slender tip from a broad base. Pollen ellipsoidal symmetric or slightly asymmetric; aperture a distal sulcus; ectexine tectate, psilate and sparsely perforate (in some collections with small sparsely distributed club-shaped spinulae) aperture margin similar; infratectum columellate; longest axis 40–60 µm [1/1]. Pistillate flowers ovoid, smaller than the staminate; sepals 3, distinct, imbricate, broadly rounded; petals 3, distinct, broadly imbricate, very briefly valvate at the apex; staminodes 3, small, triangular, at one side of the gynoecium; gynoecium ovoid, unilocular, uniovulate, stigmas scarcely differentiated, not exserted or recurved, ovule large, prominently vascularised, attached laterally in upper part of locule, hemianatropous. Fruit ovoid or ovoid-ellipsoidal, black or purplish at maturity, stigmatic remains apical; epicarp smooth when fresh, wrinkled but not pebbled when dry, mesocarp with an external and an internal layer of elongate, vertically oriented parenchyma cells with some flat, thin, longitudinal fibres between the layers, cells of the inner layer longer and overlying a layer of contiguous thickened fibres and a thin layer of ± isodiametric tannin cells adherent to the endocarp, endocarp horny, with round basal operculum and scar of seed attachment extending the length of the adaxial side to the acute apex. Seed ovoid-ellipsoidal, acute, brown, with elongate hilum and only slightly anastomosing raphe branches descending from the apex, endosperm deeply ruminate; embryo basal. Germination adjacent-ligular; eophyll bifid. Cytology: 2n = 32. (J. Dransfield & N. Uhl & C. Asmussen & W.J. Baker & M. Harley & C. Lewis, Genera Palmarum. The evolution and classification of palms. 2008)A

Relationships