Poaceae
Eragrostis

Eragrostis tridentata Cope

First published in Kew Bull. 47: 280 (1992)
This species is accepted
The native range of this species is Somalia. It is an annual and grows primarily in the desert or dry shrubland biome.

Descriptions

Morphology General Habit
Annual. Culms 6-18 cm long. Ligule a fringe of hairs. Leaf-blades 2-3 cm long; 0.5-1 mm wide.
Morphology Reproductive morphology Inflorescences
Inflorescence a panicle; shorter than basal leaves; embraced at base by subtending leaf (2-3 leaves). Panicle capitate; globose; 0.5-1 cm long. Spikelets solitary. Fertile spikelets pedicelled.
Morphology Reproductive morphology Inflorescences Spikelets
Spikelets comprising 4-8 fertile florets; with diminished florets at the apex. Spikelets elliptic, or oblong; laterally compressed; 2.2-4.2 mm long; breaking up at maturity; rhachilla persistent; retaining paleas (?). Rhachilla internodes eventually visible between lemmas.
Fertile
Spikelets comprising 4-8 fertile florets; with diminished florets at the apex. Spikelets elliptic, or oblong; laterally compressed; 2.2-4.2 mm long; breaking up at maturity; rhachilla persistent; retaining paleas (?). Rhachilla internodes eventually visible between lemmas.
Morphology Reproductive morphology Inflorescences Bracts Glume
Glumes deciduous; similar; shorter than spikelet. Lower glume lanceolate; 1.1-1.7 mm long; 1 length of upper glume; membranous; 1-keeled; 1 -veined. Lower glume lateral veins absent. Lower glume apex acute. Upper glume lanceolate; 1.1-1.7 mm long; 0.7-0.9 length of adjacent fertile lemma; membranous; 1-keeled; 1 -veined. Upper glume lateral veins absent. Upper glume apex acute.
Morphology Reproductive morphology Flowers Florets
Fertile florets divergent. Fertile lemma oblong in profile; 1.6-1.8 mm long; membranous; keeled; 3 -veined. Lemma lateral veins distinct; excurrent. Lemma apex obtuse. Palea 2 -veined. Palea keels tuberculate; pectinate (hairs 0.5mm). Apical sterile florets resembling fertile though underdeveloped.
Morphology Reproductive morphology Flowers
Lodicules 2; cuneate; fleshy. Anthers 2; 0.2 mm long.
Morphology Reproductive morphology Fruits
Caryopsis with adherent pericarp.
Distribution
Africa: northeast tropical.
Reference
Eragrostideae. TAC.
[GB]

M. Thulin et al. Flora of Somalia, Vol. 1-4 [updated 2008] https://plants.jstor.org/collection/FLOS

Type
C1, near Hobyo, Thulin & Abdi Dahir 6655 (K holo., UPS iso.)
Morphology General Habit
Annual up to 18 cm high; leaves flat
Morphology Reproductive morphology Inflorescences
Panicle 0.6–1.3 cm long, densely contracted, capitate, subtended and long-overtopped by the (2–)3 uppermost leaves
Morphology Reproductive morphology Inflorescences Spikelets
Spikelets elliptic-oblong, 2.2–4.4 mm long, 4- to 8-flowered, the florets loose and divergent, disarticulating between the florets, the rhachilla fragile; glumes subequal, lanceolate, 1.1–1.7 mm long; lemmas oblong in profile, thinly membranous, 1.6–1.8 mm long, broadly obtuse, the nerves excurrent as very short mucros, often the apex of the lemma concave between the nerves; palea-keels pectinate-ciliate with tubercle-based hairs c. 0.5 mm long; anthers 2, c. 0.2 mm long.
Distribution
C1 known only from the type.
Ecology
Altitude range 50 m.
Note
This remarkable species, discovered in 1989 has a most unusual aspect for a species of Eragrostis with the capitate inflorescence sunk between the elongated uppermost leaves, rather in the manner of some annual species of Juncus.
[FSOM]

Sources

  • Flora of Somalia

    • Flora of Somalia
    • http://creativecommons.org/licenses/by-nc-sa/3.0

  • GrassBase - The Online World Grass Flora

    • Clayton, W.D., Vorontsova, M.S., Harman, K.T. and Williamson, H. (2006 onwards). GrassBase - The Online World Grass Flora.
    • http://creativecommons.org/licenses/by-nc-sa/3.0

  • Herbarium Catalogue Specimens

    • Digital Image © Board of Trustees, RBG Kew http://creativecommons.org/licenses/by/3.0/

  • Kew Backbone Distributions

    • The International Plant Names Index and World Checklist of Vascular Plants 2023. Published on the Internet at http://www.ipni.org and https://powo.science.kew.org/
    • © Copyright 2022 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 2023. Published on the Internet at http://www.ipni.org and https://powo.science.kew.org/
    • © Copyright 2022 International Plant Names Index and World Checklist of Vascular Plants. http://creativecommons.org/licenses/by/3.0