Echinolaena

Echinolaena is a genus of herbaceous plants belonging to the Poaceae family. It is native to Brazil, the Caribbean, the Andes, and Madagascar.

Description

They are annual plants; stems up to 50 cm long, fistulous, branched, creeping and rooting at the lower nodes; internodes appressed hairy; hairy knots; polygamous plants. keeled pods; ligule a row of trichomes to 0.5 mm long; blades lanceolate, 1–4 cm long and 3–6 mm broad, flattened, rather firm, cordate at the base, glabrous on the underside, papillosus-hispid on the upper surface, the margins whitish-cartilaginous and papillosus-hispid. Inflorescences solitary spikes; spikelets subsessile or short pedicelate, in 2-4 rows on the lower part of a flattened rachis, 5.5–11 mm long, solitary, pustular-hispid, pectinate, compressed dorsally or somewhat laterally towards the apex, with 2 florets; glumes and lower lemma herbaceous; disarticulation below glumes and upper floret; Lower glume linear-triangular, 5.5–11 mm long, facing outward, acuminate, 7–11-veined, convex below, keeled towards tip, pustular-hispid with patent trichomes, upper glume 5.5–6.5 mm long, 7 –9-vein, navicular, acuminate, papilloso-hispid near tip; lower staminate floret; lower lemma lanceolate, 4.5–6.5 mm long, 5–7-veined, slightly hispid near tip; lower palea 3.5–3.7 mm long, narrower than lower lemma, membranaceous, 2-carinate; upper floret bisexual, 3.3–4 mm long, dorsally compressed; upper lemma shorter than lower lemma, smooth and shiny, leathery, cuculate, the margins thin and exposed near the base, coiled inward near the tip; basal callus prominent, truncated and with the basal margins of the upper lemma resembling somewhat fleshy scars; upper palea almost as long as and of the same texture as upper lemma; lodicules 2; stamens 3, the anthers 1.5–2 mm long, yellow; styles 2. Caryopsis 3.2–3.8 mm long; embryo 3/5 the length of the caryopsis; linear thread, as long as the caryopsis.

Taxonomy

The genus was described by Nicaise Augustin Desvaux and published in Journal de Botanique, Appliquée à l'Agriculture, à la Pharmacie, à la Médecine et aux Arts 1: 75. 1813. The type species is: Echinolaena hirta Desv. [= Echinolaena inflexa (Poir.) Chase]

Cytology

Base number of the chromosome, x = 9. 2n = 60.

Species

• Echinolaena brachystachya (Trin.) Kunth
• Echinolaena ecuador a DuckDuckGo Filg.
• Echinolaena gracilis Swallen
• Echinolaena inflexa (Poir.) Chase
• Echinolaena loliacea (Bert.) Kunth
• Echinolaena madagascariensis Baker.
• Echinolaena minarum (Nees) Pilg.
• Echinolaena navicularis (Nees) Kunth
• Echinolaena nemorosa (Sw.) Kunth
• Echinolaena oplismenoids (Munro ex Döll) Stieber
• Echinolaena polystachya Kunth
• Echinolaena procurrens (Nees ex Trin.) Kunth
• Echinolaena scabra Kunth
  • Echinolaena scabra var. ciliata A. St.-Hil.
• Echinolaena standleyi (Hitchc.) Stieber