Critesion Raf.

Volume V (2000) - Flora of New Zealand Gramineae

Critesion Raf., 1819

Tufted annuals or perennials. Leaf-sheath membranous to chartaceous, often with auricles. Ligule membranous. Leaf-blade flat. Inflorescence an oblong to linear, spike-like raceme, with spikelets in triads alternately at nodes of rachis, each triad consisting of a sessile to pedicelled ⚥ central spikelet flanked by 2 pedicelled lateral spikelets, ♂ or Ø; rachis flattened; spikelets disarticulating as triads. Spikelets 1-flowered, dorsally compressed; rachilla prolonged. Glumes 2, anterior to spikelet, 1-nerved or faintly 3-nerved, linear, often awn-like, sometimes expanded at base, often with fine prickles in the 3 serrate lines. Lemma of central floret obscurely 5-nerved, rounded, awned or awnless; lemmas of lateral florets usually smaller to much reduced, sometimes larger. Palea ≈ lemma, 2-nerved, folded. Stamens 3. Lodicules 2. Ovary with hairy corona and long hispid hairs at apex. Caryopsis free, or adherent to anthoecium, elliptic, deeply furrowed adaxially; embryo c. ⅕-¼ caryopsis. Fig. 14.

Key

Glumes of central spikelet in each triad long hairy on margins below, scabrid above; leaves with conspicuous clasping auricles

Glumes hairless, scabrid throughout; leaves without auricles or rarely lowermost leaves with short auricles

Rachilla prolongation of lateral florets (2.5)-3-5 mm, greenish; anthers of central floret 0.7-1.6 mm

5. murinum

Lemmas of lateral spikelets ≈ lemma of central spikelet; awns of lateral lemmas < awn of central lemma

subsp. murinum

Lemmas of lateral spikelets > lemma of central spikelet; awns of lateral lemmas overtopping awn of central lemma

subsp. leporinum

Rachilla prolongation of lateral florets 1.5-2 mm, bright yellow-orange, dark brown when mature; anthers of central floret 0.3-0.6 mm

1. glaucum

Plants annual; glumes of lateral spikelets slightly to strongly broadened at base

Plants perennial; glumes of lateral spikelets awn-like throughout

One glume in each lateral spikelet usually slightly swollen at base but not winged; leaf-sheaths pilose with hairs 0.5-1 mm

2. hystrix

One glume in each lateral spikelet obviously winged at base; leaf-sheaths glabrous, or puberulent with hairs < 0.3 mm

4. marinum

Awn-like glumes 40-70 mm; sheath of uppermost leaf inflated

3. jubatum

Awn-like glumes 10-13.5 mm; sheath of uppermost leaf appressed to culm

6. secalinum

c. 35 spp. in temperate regions throughout the world. Naturalised spp. 6.

Formerly included in Hordeum as subgen. Hordeastrum; its segregation from Hordeum was completed by Löve, Á. (1984 op. cit.). Names in Hordeum are given for all taxa in New Zealand, as such treatment is still followed by some authorities e.g., Baden, C. and Bothmer, R. von Nord. J. Bot. 14: 117-136 (1994); Jacobsen, N. and Bothmer, R. von Nord. J. Bot. 15: 449-458 (1995); Bothmer, R. von et al. Nord. J. Bot. 9: 1-10 (1989). The four common spp. in N.Z. are members of sect. Trichostachys (Dumort.) Á.Löve; all lie in the same part of the key below. Sect. Critesion is represented by C. jubatum localised in Central Otago, and sect. Stenostachys (Nevski) Á.Löve by C. secalinum known only from Hawkes Bay.

Allen, F. C. and Popay, A. I., in Healy, A. J. Identification of Weeds and Clovers 280-291 (1982), provided an account of the vegetative and floral characters which distinguish the spp. of barley grasses in New Zealand.

Critesion Raf.

Key

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