Buradasınız: Ana sayfa » Poaceae

Poaceae

Poaceae, John Hendley Barnhart, 1895.
Buğdaygiller.
Poaceae: Annual, biennial or perennial herbs, rarely ‘woody’ (Bamboos: Subfamily Bambusoideae), often rhizomatous or stoloniferous. Flowering stems usually cylindrical, with solid nodes and hollow intemodes, rarely solid throughout. Phyllotaxis 1/2. Leaves consisting of sheath, ligule and lamina (blade). Sheaths surrounding stem, with overlapping free or connate margins, sometimes with 2 small auricles at mouth. Ligule situated at junction of sheath and blade, either membranous or a fringe of hairs, rarely absent. Blades usually linear or filiform, often setaceous, rarely lanceolate to ovate, usually sessile and contracted at junction with sheath, rarely with a false petiole, usually with ± prominent parallel veins. Leaf epidermis with long and short cells, some of the latter usually containing silica bodies, others with corky walls. Hairs of 2 kinds often present: macro-hairs (1-celled, stout, thick-walled, visible to naked eye) and micro-hairs (microscopic, normally 2-celled, slender or globose, distal cell thin-walled). Inflorescence various, composed of florets aggregated in spikelets arranged in spikes, racemes, panicles or false racemes in which a sessile spikelet is accompanied by 1-2 pedicellate ones or their rudiments; inflorescence rarely reduced to a single spikelet. Flowers usually hermaphrodite, rarely unisexual; ovary, styles and stamens enclosed between 2 bract-like structures, the whole forming a floret; florets 1-many, inserted altemately on 2 sides of a slender, jointed axis (rachilla) subtended by bracts (glumes), the whole comprising a spikelet. Glumes (0-)1 or 2(-3), lower one sometirnes suppressed or absent. Lower bract of floret (lemma) often awned and with a thickened base (callus). Upper bract (palea) usually membranous and 2-keeled, sometimes reduced or absent. Stamens 1-3(-6) (in Turkish genera), subtended by (0-)2(-3) small hyaline scales (lodicules) and normally consisting of long, deticate filaments and 2-locular anthers dehiscing by longitudinal slits (rarely by pores). Ovary superior, 1-locular; styles usually 2; ovule 1, attached on adaxial side of loculus to a point or line visible in fruit as the hilum. Fruit a caryopsis, rarely with free, mucilaginous pericarp.
Cins anahtarı