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  1. Family: Poaceae Barnhart
    1. Piresia Swallen

      1. This genus is accepted, and its native range is Trinidad to S. Tropical America.

    [GB]

    nonem

    Habit
    Perennial. Culms erect (1/1), or geniculately ascending (1/1); 7-23.87-50 cm long; wiry. Ligule an eciliate membrane. Leaf-blade base with a brief petiole-like connection to sheath. Leaf-blades lanceolate (2), or oblong (1), or ovate (1).
    Inflorescences
    Monoecious; with male and female spikelets in the same inflorescence. Synflorescence on the same culm as leaves (1), or on a separate leafless culm. Inflorescence composed of racemes; terminal (2), or terminal and axillary (2). Racemes single; bearing few fertile spikelets; bearing 2 fertile spikelets on each (3), or 3 fertile spikelets on each (2), or 4-6 fertile spikelets on each (1). Sexes mixed. Spikelets solitary (1), or in pairs. Fertile spikelets pedicelled; 1 in the cluster. Male spikelets sessile; 1 in a cluster. Pedicels cuneate.
    Spikelets
    Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets elliptic (3), or ovate (1); dorsally compressed; 4.98-6.335-8 mm long; breaking up at maturity; disarticulating below each fertile floret. Male spikelets distinct from female; lanceolate. Male spikelet glumes absent. Male spikelet lemma muticous.
    Fertile
    Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets elliptic (3), or ovate (1); dorsally compressed; 4.98-6.335-8 mm long; breaking up at maturity; disarticulating below each fertile floret.
    Glume
    Glumes deciduous; reaching apex of florets (3), or exceeding apex of florets (1); thinner than fertile lemma. Lower glume elliptic (3), or ovate (1); 1 length of upper glume; herbaceous; without keels; 5 -veined. Lower glume lateral veins without ribs (2), or ribbed (2). Lower glume surface glabrous (3), or puberulous (1). Lower glume apex acute (2), or acuminate (2). Upper glume elliptic (3), or ovate (1); 1-1.05-1.2 length of adjacent fertile lemma; herbaceous; without keels; 3 -veined (3), or 5 -veined (1). Upper glume lateral veins without ribs (2), or ribbed (2); with cross-veins (2/2). Upper glume surface glabrous (3), or puberulous (1). Upper glume apex acute (2), or acuminate (2).
    Florets
    Fertile florets female. Fertile lemma elliptic (3), or ovate (1); indurate; without keel; 5 -veined. Lemma surface pubescent. Lemma margins exposing palea (3), or covering most of palea (1). Lemma apex truncate (1/1). Palea indurate; 2 -veined.
    Flowers
    Anthers 3.
    Fruits
    Caryopsis with adherent pericarp (1/1); ovoid (1/1). Embryo 0.2 length of caryopsis. Hilum linear (1/1); 1 length of caryopsis.
    Male
    Male spikelets distinct from female; lanceolate. Male spikelet glumes absent. Male spikelet lemma muticous.
    Distribution
    South America.

    Images

    Distribution

    Native to:

    Brazil North, Brazil Northeast, Colombia, Ecuador, French Guiana, Guyana, Peru, Suriname, Trinidad-Tobago, Venezuela

    Accepted Species

    Other Data

    Piresia Swallen appears in other Kew resources:

    Bibliography

    First published in Phytologia 11: 152 (1964)

    Accepted by

    • Govaerts, R. (2019). World Checklist of Vascular Plants (WCVP Database) The Board of Trustees of the Royal Botanic Gardens, Kew.

    Sources

    GrassBase - The Online World Grass Flora
    http://creativecommons.org/licenses/by-nc-sa/3.0

    Kew Backbone Distributions
    The International Plant Names Index and World Checklist of Selected Plant Families 2020. Published on the Internet at http://www.ipni.org and http://apps.kew.org/wcsp/
    © Copyright 2017 World Checklist of Selected Plant Families. http://creativecommons.org/licenses/by/3.0

    Kew Names and Taxonomic Backbone
    The International Plant Names Index and World Checklist of Selected Plant Families 2020. Published on the Internet at http://www.ipni.org and http://apps.kew.org/wcsp/
    © Copyright 2017 International Plant Names Index and World Checklist of Selected Plant Families. http://creativecommons.org/licenses/by/3.0