Agrostis gigantea Roth
redtop
Tufted, bright green, wide-leaved perennials, 60-120 cm, with strong rhizomes; branching intra- or extravaginal, with the extravaginal shoots spreading underground as long rhizomes. Leaf-sheath smooth, or very minutely scabrid, especially near margins. Ligule 1.5-6 mm, denticulate, taller than wide. Leaf-blade 6-15 cm × 3-8 mm, flat, finely scabrid on ribs and on margins, tip acute. Culm erect or geniculate at base, sometimes trailing, internodes glabrous. Panicle 18-30 cm, pyramidal, erect, branches spreading almost horizontally; rachis usually scabrid above, branches and pedicels closely scabrid. Spikelets 1.8-2.2 mm, green or purplish. Glumes subequal, lanceolate, acute; lower = spikelet, scabrid on upper ½ of midnerve, upper usually slightly shorter, scabrid towards tip with less noticeable prickle-teeth. Lemma 1.5-2 mm, glabrous, ovate, truncate, 3-5-nerved, lateral nerves usually very shortly excurrent, midnerve sometimes produced to very short awn subapically, or dorsally ± at midpoint, usually not projecting beyond lemma tip. Palea ½-⅔ length of lemma, bifid or ± truncate. Callus usually with very short hairs. Anthers 1.3-1.6 mm. Caryopsis c. 1 × 0.5 mm.
N.: southern Waikato; S.: Southland. Damp waste ground.
Naturalised from Eurasia.
Agrostis gigantea is the most robust of the bent grasses with the widest leaves, longest ligules and largest panicle. Levy, E. B. N.Z. J. Agric. 28: 73-91 (1924), noted that it forms a coarse, open turf, as tufts appear at fairly widely spaced intervals on the long-creeping, strong rhizome. Though redtop was extensively sown in N.Z. in the latter years of the 19th Century it has not persisted in pastures or in the wild except in southern Waikato and in Southland.
