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Leersia oryzoides

©Utah State University

Leersia lenticularis

©Utah State University

Leersia oryzoides - rhizome

©Timothy M. Jones

Leersia oryzoides

©University of Tennessee Herbarium, Knoxville

Vegetative Morphology

 
Plants usually perennial, rarely annual; terrestrial or aquatic; rhizomatous or cespitose; synoecious.
Culms 20-150 cm (occasionally longer in floating mats), erect or decumbent, often rooting at the nodes, branched or unbranched.
Leaves equitably distributed along the culm.
Sheaths open.
Auricles absent.
Ligules membranous.
Pseudopetioles absent.
Blades aerial, linear to broadly lanceolate, flat or folded, sometimes involute when dry.

Reproductive Morphology

 
Inflorescences terminal panicles, usually exserted, axillary panicles sometimes also present.
Disarticulation beneath the spikelets.
Spikelets bisexual, with 1 floret.
Florets laterally compressed, linear to suborbicular in sideview.
Glumes absent.
Calluses not stipelike, glabrous.
Lemmas and paleas subequal, chartaceous to coriaceous, ciliate-hispid or glabrous, tightly clasping along the margins.
Lemmas 5-veined, obtuse or acute to acuminate, sometimes mucronate, usually unawned.
Paleas 3-veined, unawned.
Lodicules 2.
Anthers 1, 2, 3, or 6.
Styles 2, bases fused, stigmas laterally exserted, plumose.
Caryopses laterally compressed.
Embryos about 1/3 as long as the caryopses.
Hila linear.

Species Distribution Maps

Leersia monandra Leersia lenticularis Leersia virginica
Leersia hexandra Leersia oryzoides  

Chromosome Number(s)

x = 12

Additional Notes

Named for Johann Daniel Leers (1727-1774), a German botanist and pharmacist.

Leersia is a genus of about 17 aquatic to mesophytic species, growing primarily in tropical and warm-temperate regions. Five species are native to the Flora region. Leersia is closely allied to Oryza. The possession of 1, 2, 3, or 6 stamens by various species of a single genus is not common.

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Name/Synonymy Publication Info

Leersia Sw., Prodr. 21 (1788), nom. cons. Homalocenchrus Mieg, Acta Helv. Phys.-Math. 4:307 (1760), nom. rejic. Erhartia Weber in F.H. Wigg., Prim. fl. holsat. 63 (1780), nom. superfl. Asprella Schreber, Gen. pl. 1:45 (1789), nom. superfl. Laertia Gromov, Trudy Obshch. Nauk Sostoiashchago Imp. Khar'kovsk. Univ. 1:141 (1817), nom. superfl. TYPE: Leersia oryzoides (L.) Sw., typ. cons.

Endodia Raf., Neogenyton 4 (1825). TYPE: Leersia lenticularis Michx.

Aplexia Raf., Neogenyton 4 (1825). TYPE: Leersia virginica Willd.

Blepharochloa Endl., Gen. pl. 1352 (1840). TYPE: Pharus ciliatus Retz. [=Leersia hexandra Sw.].

Pseudoryza Griff., Ic. pl. asiat. 3:pl. 144, f. 1 (1851), nom. superfl. TYPE: Pseudoryza ciliata (Retz.) Griff. [=Leersia hexandra Sw.].

Treatment from

G.L. Pyrah. Leersia in Flora of North America, volume 24. In prep. Oxford University Press.

Fact Sheet Developed By

Pedro Oñativia Lake © 2006.