Ixophorus unisetus

Ixophorus is a monotypic genus of herbaceous plants in the Poaceae family. Its only species, Ixophorus unisetus, is native to Mexico, spreading from Mexico to Brazil and Cuba.

Description

They are tussock perennials; with stems 50–140 cm long and 0.6–1 mm wide, succulent, erect, branching with age; nodes glabrous or slightly appressed, hairy; monoecious plants. Pods glabrous, carinate; ligule a lacerated or ciliated membrane, 1–2.5 mm long; blades linear, up to 75 cm long and 10–25 mm wide, flattened, lax, glabrous. Terminal and axillary inflorescences, panicles of racemes, panicle 10–25 cm long, cylindrical-ovoid, racemes numerous, simple, 2–8 cm long, scabrous; each spikelet with an underlying bristle, 7–12.5 mm long, viscid, spikelets 3.5–4.7 mm long, lanceolate and acute at anthesis, broadly ovate at maturity, subsessile in 2 rows along lower sides of rachis triketro; disarticulation below glumes, spikelet drooping as a unit; glumes unequal, herbaceous, lower glume broadly ovate, 0.7–1.5 mm long, acute, 1–3-veined, upper glume and lower lemma 3.5–4.7 mm long, concealing upper floret; lower floret staminate, with 2 lodicules and 3 stamens, the anthers 2–3.4 mm long; lower palea 2-carinate, becoming circular when mature, with a cordate base and broad chartaceous wings, much broader than the rest of the spikelet; upper floret pistillate, 2–3.3 mm long, rarely with rudimentary stamens; upper lemma shorter than spikelet, elliptic, hardened, apiculate, papillose, the margins rolled inward; palea hardened; lodicules 2; styles 2. Fruit a caryopsis; embryo ca 1/2 caryopsis length, thread 1/3 caryopsis length, elliptical.

Taxonomy

Ixophorus unisetus was described by (J.Presl) Schltdl. and published in Linnaea 31: 747, 420–422. 1861-1862.

Sinonimia

• Chamaeraphis cirrhosa (E.Fourn.) Kuntze
• Chamaeraphis schiedeana (Schltdl.) Kuntze
• Chamaeraphis uniseta (J.Presl) Kuntze
• Ixophorus palmeri (Vasey) Beetle
• Ixophorus pringlei Scribn.
• Ixophorus pringlei var. minor Scribn.
• Ixophorus pringlei var. pringlei
• Ixophorus schiedeana Schltdl.
• Ixophorus schiedeanus Schltdl.
• Panicum cirrosum (E.Fourn.) Scribn. Merr.
• Panicum palmeri Vasey
• Panicum pringlei Vasey
• Panicum schiedeanum Trin. ex Beal
• Panicum unisetum (J.Presl) Trin.
• Setaria cirrosa E.Fourn. ex Hemsl.
• Setaria cirrosa E.Fourn.
• Setaria polyneura R.A.W.Herrm.
• Setaria schiedeana (Schltdl.) E.Fourn.
• Setaria schiedeana (Schltdl.) E. Fourn. ex Hemsl.
• Setaria uniseta (J.Presl) E.Fourn.
• Setaria uniseta (J. Presl) E. Fourn. ex Hemsl.
• Urochloa uniseta J.Presl