articles de Bromus texensis (Shear) Hitchc.

Physical Description ( anglais )

fourni par USDA PLANTS text

Annuals, Terrestrial, not aquatic, Stems nodes swollen or brittle, Stems erect or ascending, Stems solitary, Stems terete, round in cross section, or polygonal, Stem internodes hollow, Stems with inflorescence less than 1 m tall, Stems, culms, or scapes exceeding basal leaves, Leaves mostly cauline, Leaves conspicuously 2-ranked, distichous, Leav es sheathing at base, Leaf sheath mostly closed, Leaf sheath hairy, hispid or prickly, Leaf sheath and blade differentiated, Leaf blades linear, Leaf blades 2-10 mm wide, Leaf blades mostly flat, Leaf blades more or less hairy, Ligule present, Ligule an unfringed eciliate membrane, Inflorescence terminal, Inflorescence an open panicle, openly paniculate, branches spreading, Inflorescence solitary, with 1 spike, fascicle, glomerule, head, or cluster per stem or culm, Inflorescence single raceme, fascicle or spike, Inflorescence with 2-10 branches, Flowers bisexual, Spikelets pedicellate, Spikelets laterally compressed, Spikelets with 3-7 florets, Spikelets solitary at rachis nodes, Spikelets all alike and fertille, Spikelets bisexual, Spikelets disarticulating above the glumes, glumes persistent, Spikelets disarticulating beneath or between the florets, Rachilla or pedicel glabrous, Glumes present, empty bracts, Glumes 2 clearly present, Glumes equal or subequal, Glumes dist inctly unequal, Glumes shorter than adjacent lemma, Glumes 1 nerved, Glumes 3 nerved, Lemmas thin, chartaceous, hyaline, cartilaginous, or membranous, Lemma 5-7 nerved, Lemma glabrous, Lemma apex dentate, 2-fid, Lemma distinctly awned, more than 2-3 mm, Lemma with 1 awn, Lemma awn less than 1 cm long, Lemma awn from sinus of bifid apex, Lemma awn subapical or dorsal, Lemma awns straight or curved to base, Lemma margins thin, lying flat, Lemma straight, Palea present, well developed, Palea membranous, hyaline, Palea shorter than lemma, Palea 2 nerved or 2 keeled, Palea keels winged, scabrous, or ciliate, Stamens 3, Styles 2-fid, deeply 2-branched, Stigmas 2, Fruit - caryopsis, Caryopsis ellipsoid, longitudinally grooved, hilum long-linear, Caryopsis hairy at apex.

licence: cc-by-nc-sa-3.0

compilateur: Dr. David Bogler
source: Missouri Botanical Garden
source: USDA NRCS NPDC

original: visiter la source
site partenaire: USDA PLANTS text

Bromus texensis ( anglais )

fourni par wikipedia EN

Bromus texensis, the Texas brome, is an annual grass native to Texas.

Description

The culms of Bromus texensis reach a height of 30–75 cm (12–30 in) in a spreading or erect fashion. The culms have three to five nodes with downward hairs. The leaves are hairy (pubescent to pilose), measuring 7–20 cm (2.8–7.9 in) long and 3–7 mm wide. The ligules of the leaves are 2–3 mm long with hairs on their back.^[1]

The inflorescence is an erect or drooping panicle, 8–15 cm (3.1–5.9 in) long. The branches of the panicle are smooth and hairless, growing up to 9 cm (3.5 in) long. The spikelets are 2–3 cm (0.79–1.18 in) long and have four to seven minuscule florets. The first glume is 6–9 mm long with a single nerve, and the second glume is 8–10.5 mm long with three nerves. The lemmas are 9–15 mm long, with three or seven nerves. The lemmas are olive green and smooth, sometimes rough on their margins. The palea is shorter than the lemma and has rough nerves.^[1]

Bromus texensis is the only grass in section Bromopsis that is a true annual.^[2]

Distribution and habitat

Bromus texensis is restricted to central and south-east Texas, occurring on rocky soils in Bexar, Duval, Goliad, Nueces, and Travis counties. The type locality is in Bexar county, and only one collection of the species has been made in the others. Although one specimen has been reported from Mexico, it was later discovered to be Bromus anomalus.^[1]