Parajubaea Burret, Notizbl. Bot. Gart. Berlin-Dahlem 11: 48 (1930)

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  • Large, solitary, unarmed, pleonanthic, monoecious palms. Stem tall, stout or rather slender, grey, obscurely ringed with leaf scars. Leaves pinnate, slightly arching, sometimes twisted, marcescent; sheath not forming a crownshaft, disintegrating into a mass of rather fine to coarse brown fibres; petiole short, adaxially flat, abaxially rounded, glabrous, margins fibrous at least basally; rachis longer than the petiole, tapering, rounded adaxially, grooved laterally, rounded abaxially; leaflets numerous, regularly arranged or in groups of 2–5 in one plane, narrow, elongate, single-fold, pointed distally, tips shortly bifid to oblique, glabrous adaxially, abaxially sparsely scaly and with linear ramenta along the midribs, midrib prominent adaxially, the only large vein, transverse veinlets not evident. Inflorescences interfoliar, erect, becoming pendulous in fruit, branched to 1 or 2 orders; peduncle elongate, dorsiventrally flattened, glabrous; prophyll short, 2-keeled, opening apically, not exserted from the leaf sheath; peduncular bract much longer than the prophyll, narrowly tubular, tapering to a short apical beak, woody, deeply grooved, splitting abaxially and eventually marcescent, glabrous or covered with tomentum; several short, incomplete peduncular bracts present; rachis about as long as or shorter than the peduncle, bearing rather distant, spirally arranged, short, wide, centrally pointed bracts subtending rachillae; rachillae erect and closely appressed to the rachis, rather short, stout, sometimes zigzag, glabrous or with caducous tomentum, in Parajubaea cocoides distally with a few short branches of the 2nd order, rachillae bearing spirally arranged, very short, wide, pointed bracts subtending few triads (2–8) at the base and paired or solitary staminate flowers throughout most of the rachilla length, floral bracteoles short, rounded to pointed. Staminate flowers asymmetrical, ± pointed; sepals 3, distinct, imbricate basally, keeled, acute; petals 3, distinct, much larger than the sepals, angled, valvate; stamens 13–15, filaments erect, awl-shaped, ± inflexed; anthers linear, emarginate apically, sagittate basally, dorsifixed near the middle, introrse; pistillode short, briefly trifid. Pollen ellipsoidal, frequently elongate, usually with either slight or obvious asymmetry; aperture a distal sulcus; ectexine tectate, finely perforate, perforate and micro-channelled or perforate-rugulate, aperture margin may be slightly finer; infratectum columellate, longest axis 41–60 µm [2/3]. Pistillate flowers broadly ovoid, larger than the staminate; sepals 3, distinct, imbricate, margins irregular; petals 3, distinct, imbricate with briefly pointed, valvate tips; staminodes united in a shallow cupule, unlobed or with 3 pointed tips; gynoecium broadly ovoid, trilocular, triovulate, glabrous or tomentose, stigma short, rounded, trilobed, ovules laterally attached, form unknown. Fruit oblong-ovoid, beaked, perianth persistent on fresh fruit; epicarp smooth, mesocarp rather thin, fibrous, endocarp thick, very hard, with shining lines internally, externally irregularly sculptured with 3 prominent ridges (P. torallyi and P. sunkha), or surface and thickness irregular, ridges not prominent (P. cocoides), pores 3, basal, sunken. Seeds 1–3, rounded, raphe elongate, lateral, endosperm homogeneous, hollow; embryo subbasal. Germination and eophyll not recorded. Cytology not known. (J. Dransfield & N. Uhl & C. Asmussen & W.J. Baker & M. Harley & C. Lewis, Genera Palmarum. The evolution and classification of palms. 2008)A

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