Hordeum secalinum Schreb., Poaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  yes

Other Latin names:  Critesion secalinum (Schreb.) Á. Löve; Hordeum pratense Huds.

Common name(s): [more details]

English: false-rye barley, knotted barley, meadow barley

Habit:  grass

Description:  "Annual. Culms 20-80 cm long; 3-5 -noded. Leaf-sheath oral hairs lacking. Leaf-sheath auricles falcate. Ligule an eciliate membrane; 0.5-1 mm long. Leaf-blades 2-15 cm long; 2-6 mm wide. Inflorescence composed of racemes. Racemes 1; single; linear; bilateral; 2-8 cm long. Rhachis fragile at the nodes; flattened. Spikelet packing broadside to rhachis. Rhachis internodes oblong; falling with spikelet above. Spikelets in threes. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 2 in the cluster. Pedicels oblong. Sterile spikelets: Companion sterile spikelets well-developed; containing empty lemmas, or male; lanceolate; dorsally compressed; 4-6 mm long; shorter than fertile, or as long as fertile; deciduous with the fertile. Companion sterile spikelet glumes subulate; 7-14 mm long; wingless; eciliate on margins. Companion sterile spikelet lemmas 1; exserted from glumes; 4-6 mm long; 1-awned; with 2-3 mm long awn. Fertile spikelets: Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets lanceolate; dorsally compressed; 6-9 mm long; falling entire; deciduous with accessory branch structures. Glumes collateral; similar; gaping. Lower glume subulate; 7-14 mm long; 1 length of upper glume. Lower glume margins eciliate. Upper glume subulate; 7-14 mm long. Upper glume margins eciliate. Florets Fertile lemma lanceolate; 6-9 mm long; coriaceous; without keel; 5 -veined. Lemma surface smooth. Lemma apex acuminate; awned; 1 -awned. Principal lemma awn 6-12 mm long overall; limb scabrous. Flower: Anthers 3; 3-4 mm long. Ovary pubescent on apex. Caryopsis with adherent pericarp; ellipsoid; sulcate on hilar side; hairy at apex. Embryo 0.2 length of caryopsis. Hilum linear; 1 length of caryopsis"  (GrassBase).

Habitat/ecology:  (no habitat/ecology info known by PIER)

Propagation:  Seed

Native range:  Madeira Islands, Algeria, Europe; naturalized elsewhere (GRIN).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Chile (offshore islands) Juan Fernández Islands	Isla Más a Tierra (Robinson Crusoe Island)	introduced invasive	Atkinson, Rachel/Sawyer, John (2011)
Chile (offshore islands) Juan Fernández Islands	Isla Más a Tierra (Robinson Crusoe Island)	introduced invasive	Danton, Philippe/Perrier, Christophe/Martinez Reyes, Guido (2006) (p. 554)

Pacific Rim
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Australia Australia (continental)	Australia (continental)	introduced	U.S. Dept. Agr., Agr. Res. Serv. (2011) Victoria
New Zealand New Zealand	New Zealand (country)	introduced	U.S. Dept. Agr., Agr. Res. Serv. (2011)

Additional information:
Additional online information about Hordeum secalinum is available from the Hawaiian Ecosystems at Risk project (HEAR).

Information about Hordeum secalinum as a weed (worldwide references) may be available from the Global Compendium of Weeds (GCW).

Taxonomic information about Hordeum secalinum may be available from the Germplasm Resources Information Network (GRIN).

References:

Atkinson, Rachel/Sawyer, John. 2011. Naturalized species in the Juan Fernández Archipelago, Chile. Unpublished spreadsheet.

Clayton, W.D./Harman, K.T./Williamson, H. 2011. World Grass Species: Descriptions, Identification, and Information Retrieval [GrassBase - The Online World Grass Flora]. The Board of Trustees, Royal Botanic Gardens, Kew.

Danton, Philippe/Perrier, Christophe/Martinez Reyes, Guido. 2006. Nouveau catalogue de la flore vaculaire de l'archipel Juan Fernández (Chile) [Nuevo catálogo de la flora vacular del Archipélago Juan Fernández (Chile)]. Acta Bot. Gallica 153(4):399-587.

U.S. Dept. Agr., Agr. Res. Serv. 2011. National Genetic Resources Program. Germplasm Resources Information Network (GRIN). Online searchable database.