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giant cutgrass, water millet

Habit Plants perennial; rhizomatous, rhizomes to 1.5 cm thick. Plants annual or perennial.
Culms

1-4 m tall, to 3.5 cm thick, erect or decumbent, glabrous, readily rooting at the nodes when decumbent and producing leafy buds.

annual, sometimes woody, hollow or solid.

Sheaths

thick, glabrous;

ligules to 2 cm, glabrous;

blades to 1 m long, 6-30 mm wide, sometimes scabrous, bluish-green, margins scabrous.

Leaves

distichous;

sheaths open;

auricles sometimes present;

abaxial ligules absent;

adaxial ligules membranous, scarious, or of hairs;

pseudopetioles sometimes present;

blades rarely cordate or sagittate at the base, venation parallel;

mesophyll not radiate;

adaxial palisade layer usually absent;

fusoid cells sometimes present;

arm cells absent or present;

Kranz anatomy not developed;

midribs simple or complex;

adaxial bulliform cells present;

stomates with dome-shaped or triangular subsidiary cells;

bicellular microhairs present, terminal cells tapered;

papillae sometimes present.

Panicles

to 80+ cm long, usually 4-20 cm wide, open;

pedicels to 10 mm long, apices 0.1-0.4 mm wide.

Inflorescences

panicles, racemes, or spikes, rarely with bracts other than those of the spikelets;

disarticulation usually above the glumes, sometimes beneath the spikelets or at the base of the primary branches.

Spikelets

bisexual or unisexual, with 1 pistillate or bisexual floret, sometimes with 1-2 sterile florets below the functional floret.

Glumes

absent or 2;

lemmas without uncinate hairs, sometimes terminally awned, awns single;

paleas well-developed, lacking in sterile florets;

lodicules 2, usually membranous, rarely fleshy, heavily vascularized;

anthers (1)3-6(16);

ovaries glabrous, without an apical appendage;

styles 2, free to the base to fused throughout, 2-branched.

Fruits

caryopses or achenes;

hila long-linear;

endosperm without lipid, usually containing compound starch grains, rarely with simple starch grains;

embryos to 1/3 the length of the caryopses;

epiblasts usually present;

scutellar cleft usually present;

mesocotyl internode absent or very short;

embryonic leaf margins usually overlapping.

Achenes

2.5-4 mm long, 1-2 mm wide, ellipsoid or obovoid, smooth, lustrous, beaked by the persistent style base.

Staminate

lemmas 5-10 mm, lanceolate to elliptic, glabrous, acuminate or awned, awns to 2 mm;

paleas acuminate or awned, awns to 1 mm;

anthers 2.5-5 mm.

Pistillate

lemmas 4-8 mm, ovate or elliptic, awned, awns to 9 mm;

paleas caudate-acuminate or awned, awns to 1 mm;

style bases 1-3 mm, stigmas 2-6 mm, conspicuously exserted.

x

=12 (10,15,17).

2n

= 24.

Zizaniopsis miliacea

Poaceae subfam. ehrhartoideae

Distribution
from FNA
AL; AR; FL; GA; IL; KY; LA; MD; MO; MS; NC; OK; SC; TN; TX; VA
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[BONAP county map]
Discussion

Zizaniopsis miliacea grows in shallow, fresh- or brackish-water marshes, swamps, streams, lakes, and ditches. It is most common on the eastern coastal plain of the United States, extending south to Florida and west to Illinois, Oklahoma and Texas. It has also been reported growing as a disjunct in central Mexico (McVaugh 1983).

Fox and Haller (2000) found that decumbent flowering culms readily produce roots and axillary shoots at the nodes. The decumbent culms act as functional stolons, allowing for rapid colonization; thus plants become established up to 3-4 m away from the parent plant.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

The Ehrhartoideae encompasses three tribes, one of which, the Oryzeae, is native to the Flora region; the Ehrharteae is represented by introduced species. The third tribe, Phyllorachideae C.E. Hubb., is native to Africa and Madagascar. It was included in the subfamily on the basis of its morphological similarity to the other two tribes. There are approximately 120 species in the Ehrhartoideae. They grow in forests, open hillsides, and aquatic habitats.

Molecular data provide strong support for the close relationship of the Oryzeae and Ehrharteae (Grass Phylogeny Working Group 2001). Morphologically, they are characterized by spikelets that have a distal unisexual or bisexual floret with up to two proximal sterile florets, and the frequent presence of six stamens in the staminate or bisexual florets.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Key
1. Spikelets with 2 sterile florets below the functional floret, both well-developed, at least the upper sterile floret as long as or longer than the functional floret; glumes from 1/2 as long as the spikelets to exceeding the florets; culms not aerenchymatous; plants of dry to damp habitats
Ehrharteae
1. Spikelets with 0-2 sterile florets below the functional floret, when present, sterile florets 1/8 - 9/10 as long as the functional floret; glumes absent or highly reduced; culms aerenchymatous; plants of wet habitats
Oryzeae
Source FNA vol. 24, p. 52. FNA vol. 24, p. 32. Author: Grass Phylogeny Working Group;.
Parent taxa Poaceae > subfam. Ehrhartoideae > tribe Oryzeae > Zizaniopsis Poaceae
Name authority (Michx.) Doll & Asch. Link
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