Flora of New Zealand Series

Kentucky bluegrass

Rather narrow, loose to compact perennial tufts c. 10-50 cm from slender rhizomes with ± soft, bright green to greyish green leaves < culms; branching extravaginal at plant base, sometimes intravaginal above; leaf-blades persistent. Leaf-sheath light green to very light brown, membranous to ± coriaceous, distinctly ribbed, glabrous, or slightly short-scabrid to shortly hairy near ligule. Ligule in lower leaves 0.2-0.5 mm, truncate, often very short-ciliate, and abaxially minutely hairy, in upper leaves 1-2 mm, apically glabrous, entire and rounded. Leaf-blade (1.5)-10-20-(35) cm × (1.5)-2-4 mm, flat or folded, subcoriaceous, glabrous or sparsely finely hairy especially near ligule or only adaxially; margins sparsely scabrid to smooth, sometimes hairy near ligule; midrib scabrid near blunt, curved tip. Culm (5)-20-55 cm, internodes glabrous. Panicle (2)-5-10-(15) cm, ovate to pyramidal, or oblong, erect or nodding, loose and open to somewhat dense and contracted; rachis glabrous, branches in clusters of 3-5, spreading, filiform, flexuous, smooth or finely scabrid with spikelets clustered at tips. Spikelets 4-6 mm, (2)-3-6-flowered, light green or purplish. Glumes ± unequal, acute, membranous, midnerve scabrid; lower 1.5-3 mm, 1-3-nerved, narrow-ovate, upper 2-3.5-(4) mm, 3-nerved, ovate-elliptic. Lemma 2.5-4 mm, 5-(7)-nerved, ovate-oblong, subobtuse to acute, midnerve and marginal nerves thinly to densely hairy in lower ½, midnerve finely scabrid above hairs, internerves glabrous. Palea 2-3 mm, keels finely scabrid, interkeel glabrous. Callus with tuft of long crinkled hairs. Rachilla c. 0.5 mm, glabrous or very minutely sparsely papillose; prolongation twice as long. Lodicules 0.6-0.8 mm. Anthers 1.2-1.7 mm. Caryopsis c. 1.5 × 0.5 mm, tightly enclosed by anthoecium.

N.; S.: throughout; St.; Ch., A., C. Lowland to alpine in grassland and pasture, cultivated or waste ground.

Naturalised from Eurasia.

Poa pratensis is treated here in the broad sense, including P. angustifolia L. and P. subcaerulea Sm. In N.Z. the name P. angustifolia may be applied to greyish green, densely caespitose, narrow-leaved plants. Poa subcaerulea which Allan, H. H. T.R.S.N.Z. 65: 2 (1935) suggested was probably widely distributed in North Id, is distinguished from P. pratensis and P. angustifolia in having scattered, ± solitary stems, and equal, acuminate, 3-nerved glumes.

Hooker formally named a New Zealand plant of Kentucky bluegrass as P. anceps var. γ breviculmis Hook.f., Fl. N.Z. 1: 306 (1853); Lectotype: K (lowest specimen)! J. D. H[ooker] Bay of Islands [1841] (designated by Edgar 1986 op. cit. p. 459).