Echinochloa polystachya

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Scientific name

Echinochloa polystachya (Kunth) Hitchc.

Subordinate taxa:
Echinochloa polystachya (Kunth) Hitchc. var. spectabilis (Nees ex Trin.) Mart. Crov.

Synonyms

Echinochloa spectabilis (Nees ex Trin.) Link
Panicum spectabile Nees ex Trin.
Psuedechinolaena polystachya (H.B.K.) Stpf.
Iplismenus polystachyusKunth.

Family/tribe

Family: Poaceae (alt. Gramineae) subfamily: Panicoideae tribe: Paniceae.

Common names

aleman, German grass (Australia, Panama);  creeping river grass (North America);  pasto alemain (Venezuela);  pardegrao, prasigrasi (Surinam).

Morphological description

Echinochloa polystachya is an aquatic or sub-aquatic perennial with course culms 1–2.5 m high, thick in the lower parts, from long rhizomes, internodes glabrous, nodes glabrous or obscurely pubescent.  Ligule a rim of stiff, yellow hairs to 4 mm long.  Leaf blades 20–60 cm long 10–25 mm wide, scabrous on the margin.  Panicles mostly 15–25 mm long, dense, the short, thick branches ascending.  Spikelets 5–7 mm long, lanceolate.  Upper floret hermaphrodite, 5–6 mm long, with awn 5–7 mm long, or mucronate;  lower floret staminate with awn on lemma 7–17 mm long.
‘Amity’ differs from the species norm in having flowering culms 100–200 cm long, 7–10-noded, nodes glabrous.  Ligule hairs 1–1.5 mm long.  Leaf blades 30–36 cm long, 10–12 mm wide.  Panicle axis 20–30 cm long.  Spikelets 4.5–5.5 mm long, 1.7–2.0 mm wide.  The most distinctive differences are the much shorter mucros of the lemmas of ‘Amity’;  the lemmas of E. polystachya are normally awned rather than mucronate .
‘Amity’ has flat linear, glabrous leaves, tapering to a narrow apex, rounded or auriculate at the base.  Panicle axis scabrous;  primary branches with spikelets appressed to the rachis, 2.5–9.0 cm long.  Pedicels 0.2–2.0 mm long, scabrous, disarticulation at the base of the spikelet.  Spikelets plano-convex, lanceolate.  Lower glume 2.5–3.0 mm long, ovate-lanceolate.  Upper glume 4.5–5.5 mm long, lanceolate 6–7-nerved, chartaceous, glabrous, strigose on the nerves apically, acuminate, 5.0–5.5 mm long.  Lemma of lower floret 5.0–5.5 mm x 1.0–1.5 mm, lanceolate, chartaceous, 7–9-nerved, the surface glabrous, acuminate, with mucro 1.0–1.5 mm long;  lower palea linear, acute.  Upper floret lemma 4.5 mm long, white, cartilaginous, smooth, ovate-lanceolate, acuminate, with mucro 0.5 mm long;  upper palea cartilaginous, smooth, enclosed at its apex by the lemma .

Distribution

Native to:
North America:  Mexico, USA - Florida, Louisiana, Texas.
Mesoamerica:  Belize, Costa Rica, Honduras, Nicaragua, Panama.
Caribbean:  Antigua and Barbuda, Cuba, Dominican Repub