Arecaceae

Allagoptera Nees

First published in M.A.P.zu Wied-Neuwied, Reise Bras. 2: 335 (1821)
This genus is accepted
The native range of this genus is Brazil to Bolivia and Argentina (Misiones).

Descriptions

Vernacular
For common names, see Glassman (1972).
Diagnostic
Small acaulescent or moderate erect palms native to eastern South America, with spicate inflorescences; the staminate flowers are very densely packed and with 6 to over 100 stamens, fruit tending to be rather irregularly shaped because of close-packing.
General Description
Small, moderate or tall, acaulescent or erect, solitary or clustered, armed or unarmed, pleonanthic, monoecious palms. Stem erect, or very short and subterranean, occasionally branching dichotomously, rough and closely ringed with leaf scars. Leaves pinnate, marcescent; sheath short to long, tubular but splitting adaxially when young, becoming woody or soft fibrous, slightly expanded at the base to the petiole, sometimes finely striate and covered with whitish, rusty spotted tomentum; petiole short to long, slender to robust, deeply channelled adaxially, rounded abaxially, margins smooth or roughly toothed to spiny, tomentose abaxially like the sheath; rachis arched or straight, adaxially channelled, distally flattened, abaxially rounded, or triangular in cross-section, glabrous or scaly; leaflets single-fold, inserted regularly or in groups, long, narrow, tapering, pointed, or 2-lobed and split apically, a midrib evident on both surfaces, large scales present or absent abaxially along the midrib, glabrous or glaucous throughout, or silvery beneath, transverse veinlets apparent adaxially. Inflorescences solitary, interfoliar, erect or pendulous, unbranched; peduncle short to very long, circular in cross-section; prophyll tubular, thin, dorsiventrally flattened, 2-keeled laterally, glabrous or scaly, becoming fibrous, opening apically; peduncular bract 1, long, basally slender, sometimes appearing stalked, inflated above, tapering to a beak, woody, ± plicate, splitting abaxially; rachis bearing close triads throughout the lower 1/2 or more of its length and pairs of staminate flowers distally, staminate flowers shed early, leaving a long, bare, pointed tip on the rachis at pistillate anthesis, bracts subtending triads ovate, pointed, those subtending staminate flower pairs with longer pointed tips, bracts adnate laterally to the rachis and to the bases of adjacent bracts, forming a curved depression surrounding the flower pairs, floral bracteoles inconspicuous. Staminate flowers large, asymmetrical, ovoid to obovoid, angled, those of the triads sometimes borne on long, ± flat pedicels curved around the pistillate flower, distal, paired staminate flowers sessile; sepals 3, narrow, connate basally for ca. 1/4 their length, widely separated, pointed, keeled, margins entire or crenate; petals 3, distinct, irregular, angled, triangular, valvate, slightly–4 times longer than the sepals, the tips thickened; stamens 6–ca. 100, filaments awl-shaped, ± united at the base, erect, sometimes flexible and variously bent and curved, anthers somewhat irregular, short to elongate, curved but not twisted, dorsifixed near the base of a prominent connective or toward the middle, sometimes versatile, latrorse or introrse; pistillode lacking or slender, conical, ca. 1/2 as long as the stamens. Pollen ellipsoidal, may be elongate and/or pyriform, usually with either slight or obvious asymmetry; aperture a distal sulcus; ectexine tectate, finely perforate, or perforate-rugulate, aperture margin may be slightly finer; infratectum columellate; longest axis 20–50 µm; post-meiotic tetrads tetrahedral, rarely tetragonal or rhomboidal [4/5]. Pistillate flowers smaller or slightly larger than the staminate, globose; sepals 3, distinct, broadly imbricate, tips valvate in bud; petals 3, distinct, about as long as the sepals, broadly imbricate, tips valvate; staminodes connate in a low, shallowly lobed cupule; gynoecium ovoid or obovoid, trilocular, triovulate, stigmas narrow, recurved between the petal apices at anthesis, ovules laterally attached, anatropous. Fruit obovoid, angled by mutual pressure, greenish-yellow or brown, usually 1-seeded, stigmatic remains represented by an apical knob, perianth enlarged and persistent; epicarp glabrous or with woolly scales, mesocarp fibrous and fleshy, endocarp hard but relatively thin, or thick and bony, smooth, with 3 pores near the base, internally with 3, broad, shining lines. Seed obovoid or elongate, basally attached, hilum small, raphe wide with large curved and small anastomosing branches, endosperm hard, with or without a central hollow, homogeneous or shallowly ruminate; embryo basal to subbasal. Germination remote-tubular; eophyll entire or briefly bifid. Cytology: 2n = 32.
Distribution
Five species in Brazil and Paraguay.
Biology
In loose sand on beaches, on dunes, in open tree and scrub woodland, among rocks on sandstone hills, in dry grassy or shrubby vegetation zones (cerrado) or in open areas in the mountains.
Morphology
Leaf (Moraes 1996a), root (Seubert 1998a, 1998b), stamen development (Uhl 1988).
[PW]

Sources

  • Herbarium Catalogue Specimens

  • Kew Backbone Distributions

    • The International Plant Names Index and World Checklist of Vascular Plants 2024. Published on the Internet at http://www.ipni.org and https://powo.science.kew.org/
    • © Copyright 2023 World Checklist of Vascular Plants. http://creativecommons.org/licenses/by/3.0

  • Kew Names and Taxonomic Backbone

    • The International Plant Names Index and World Checklist of Vascular Plants 2024. Published on the Internet at http://www.ipni.org and https://powo.science.kew.org/
    • © Copyright 2023 International Plant Names Index and World Checklist of Vascular Plants. http://creativecommons.org/licenses/by/3.0

  • Palmweb - Palms of the World Online

    • Palmweb 2011. Palmweb: Palms of the World Online. Published on the internet http://www.palmweb.org. Accessed on 21/04/2013
    • Content licensed under Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License http://creativecommons.org/licenses/by-nc-sa/3.0