Marojejya Humbert, Mém. Inst. Sci. Madagascar, Sér. B, Biol. Vég. 6: 92 (1955)

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Biology And Ecology

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Description

  • Stout, solitary, unarmed, monoecious, pleonanthic palms. Stem erect, obscurely ringed with leaf scars, internodes short, sometimes with short root spines. Leaves numerous, massive, pinnate or ± entire, the crown often filled with fibres; sheath with or without rounded auricles; petiole absent or thick and wide at the base, gradually tapering to the rachis, adaxially channelled, abaxially rounded, densely covered with caducous, dense brown scales; rachis adaxially deeply channelled, abaxially rounded basally, becoming laterally channelled distally, densely scaly at the base, blade undivided for ca. 1/4 to the entire length, where not entire, distally irregularly divided into, 1–several-nerved, obtuse leaflets with decurrent bases, the blade eventually splitting irregularly, abaxially with scattered irregular bands of caducous, chocolate-brown scales, numerous fine, longitudinal veins between the major ribs, transverse veinlets not evident. Inflorescences unisexual (but see below), hidden among the leaf bases beneath debris, branching to 1 order, staminate and pistillate inflorescences basically similar but staminate with more numerous slender and longer branches; peduncle large, slightly flattened, short, densely covered in dark brown scales; prophyll tubular, 2-keeled, strongly flattened, splitting longitudinally, thinly coriaceous, bearing numerous caducous, dark brown scales; basal peduncular bract similar to the prophyll but smaller, subsequent peduncular bracts numerous, crowded, spirally arranged, incomplete, acute to acuminate, stiff, ± erect, gradually diminishing in size distally; rachis shorter than the peduncle, bearing spirally arranged rachillae, each subtended by a conspicuous, acute or acuminate bract; staminate rachillae ± equal in length, stout, catkin-like, somewhat flexuous, densely covered in brown tomentum; rachilla bracts conspicuous, paired, narrow, triangular, subtending densely crowded, paired staminate flowers except near the base and at the tip where solitary staminate flowers present, flowers abortive at the very base, rarely a few pistillate flowers present at the base (as a monstrosity), distal bracts forming pits; floral bracteoles 2, well-developed, acute, ciliate margined. Staminate flowers rather small, somewhat asymmetrical due to close packing; sepals 3, free, unequal, narrow, ovate, keeled, chaffy, ciliate margined, tending to be widely separated; petals 3, ± boat-shaped, valvate, coriaceous, connate basally for 1/3 their length and adnate to the receptacle; stamens 6, filaments basally connate, the distinct portions flattened, tapering, elongate, inflexed at the tip, anthers medifixed, ± versatile, latrorse; pistillode small, 3 lobed. Pollen ellipsoidal asymmetric, occasionally lozenge-shaped, pyriform or oblate triangular; aperture a distal sulcus, infrequently a trichotomosulcus; ectexine tectate, perforate-rugulate, aperture margin similar, or slightly finer; infratectum columellate; longest axis ranging from 34–37 µm [2/2]. Pistillate rachillae shorter, thicker, and fewer than the staminate, densely brown tomentose, bearing crowded, spirally arranged, triangular bracts forming the lower lips of shallow pits, each pit bearing 3 membranous bracteoles, 2 very small abortive staminate flowers and a large solitary pistillate flower. Pistillate flowers much larger than the staminate, obpyriform, somewhat asymmetrical; sepals 3, distinct, somewhat chaffy, ovate with triangular tips, ± striate; petals 3, distinct, similar to the sepals but larger and with short, triangular, valvate tips; staminodes 6, narrow, triangular; gynoecium gibbous, unilocular, uniovulate, gradually tapering to 3, large, triangular, recurved stigmas, ovule large, pendulous, campylotropous. Fruit asymmetrically globular, perianth persistent, stigmatic remains forming a large lateral beak; epicarp smooth, mesocarp thin, granular, endocarp composed of several layers of broad, soft anastomosing fibres closely adhering to the seed. Seed irregularly rounded, flattened, or ± kidney-shaped, smooth or grooved and ridged, subapically attached, endosperm homogeneous; embryo basal, opposite the fruit attachment. Germination adjacent-ligular; eophyll bifid, with or without a petiole. 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

Anatomy

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