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1Source

Supposedly in Argentina. Brazil, and Uruguay

2Description

Plants perennial, shortly rhizomatous, with numerous sterile shoots. Culms 12-70 cm tall, erect, with many nodes, glabrous, retrorsely scabrous below the panicle.

Leaves: sheaths closed, retrorsely scabrous, glabrous or almost glabrous to densly pilose, compressed, occasionally with smal recurved teeth on the dorsal keel; ligules 2.5-7 mm long, entire, membranous, hyaline, frequently lacerate; blades 1-15 cm long, 1-2 mm wide, linear or subfiliform, convolute or involute, more or less stuff, lower surface glabrous or pilose, upper surface hispid, margins ciliate.

Panicles 5-27 cm long, erect, open, lax, wtih many spikelets; rachis lighly scabrous; branches usually divergent, slightly scabrous; secondary branches appressed; pedicels filiform, curved, glabrous or sparsely hairy near the spikelet, disarticulating at maturity.

Spikelets dorsally compressed, somewhat nodding to horizontal, stramineous or purplish-straw-colored near the veins, the lowest floret bisexual, the other 2-3 sterile and  wrapped around each other, forming the rudiment.

Glumes 2 dissimilar in shape and size; lower glume 5-8 mm long, 3.5-6.5 mm wide, obovate or flabellate, almost flat at maturity, papery with a wide membranous-hyaline marginal border, 5-7-veined, veins with short anastomes, midvein abotu 1/2 as long as the glume, upper margin erose; upper glumes 3.5-5 mm long, 1.5-2.5 mm wide, oblanceolate, papery near the veins, membranous-subhyaline elsewhere, 3(-5) veined, veins anastomising, midvein subequal to the lateral veins, about 3/4 the length of the glume, tip obtuse or acute, somewhat concave; rachilla glabrous.

Lowest floret bisexual; callus with tiny hairs; lemma 4-5 mm long, 1.5-2 mm wide, lanceolate, mostly papery, lateral and distal margins membranous-hyaline, back striate-scabrous, many veined, marginal veins with hairs about 0.5-1 mm long, the remainder glabrous (including the basal portion); palea (3)3.5-4 mm long, 0.8-1 mm wide (excluding the sides), 2-veined, veins ciliolate, intercostal region rough; lodicules 1, 0.2-0.3 mm long, connate, truncate; stamens 3, anthers 0.8-1 mm long. linear.

Caryopsis 1.5-1.8 mm long, 0.6-0.7 mm in diameter, obvoid, brown, shiny; hilum linear scutellum about 1/3 the length of the caryopsis, obovate.

Rudiment obpyriform, truncate, paleas absent or vestigial.

4Distribution

Argentina: Chaco, Santiago del Estero, Santa Fe, San Juan, San Luis, Cordoba, Santa Fe, Corrientes, Entre Rios, La Pampa, Buenos Aires

Brazil: Rio Grande do Sul

Uruguay: Cerro Largo, Colonia, Montevideo, Paysandu, Rio Negro, Paysandu, Soriano

5Ecology

Melica argyrea is common in the grasslands within its distributiona area, uncommon in the mountains.

6Flowering time

August to November.

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7Chromosome number

2n = 18 (Quarin, C. L. 1977. Recuentos cromosómicos en gramíneas de Argentina subtropical. Hickenia. 1: 73-78. )

8Comparison

Melica argyrea is easily disnguished from Melica bonariensis by its pedicels that are either glabrous or sparsely hair near the spikelet, by the obovate or flabeelate shape of its lower glume by the usually cuneate-obtuse upper glumes and by open (pyramidal) panicle and the obovoid brown caryopses.

Nomenclature & Synonyms

Melica argyrea Hackel in TROPICOS

Translated and/or edited by

Mary E. Barkworth, Intermountain Herbarium, Utah State University.