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The grass genera of the world

L. Watson, T.D. Macfarlane, and M.J. Dallwitz

Simplicia Kirk

Habit, vegetative morphology. Perennial; caespitose. Culms herbaceous. Culm nodes glabrous. Leaves not basally aggregated; non-auriculate. Leaf blades narrow; without cross venation; persistent. Ligule an unfringed membrane; not truncate; 2–3 mm long.

Reproductive organization. Plants bisexual, all with bisexual spikelets; with hermaphrodite florets.

Inflorescence. Inflorescence paniculate; open, or contracted; espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent. Spikelets not secund; pedicellate.

Female-fertile spikelets. Spikelets 2.5 mm long; compressed laterally; disarticulating above the glumes. Rachilla prolonged beyond the uppermost female-fertile floret; hairy; the rachilla extension naked.

Glumes two; minute; very unequal to more or less equal; shorter than the spikelets; shorter than the adjacent lemmas (the upper less than 1/4 the length of the floret); pointed; awnless; non-carinate; similar. Lower glume 1 nerved. Upper glume 1–3 nerved. Spikelets with female-fertile florets only.

Female-fertile florets 1–2. Lemmas decidedly firmer than the glumes (membranous); not becoming indurated; pointed (acute); awnless, or awned (with or without an awnlet). Awns if present, 1; median; dorsal to apical; from near the top (subapical); non-geniculate. Lemmas hairless (but tuberculate-scabrid); carinate; 3 nerved. Palea present; relatively long; 1-nerved, or 2-nerved; one-keeled. Lodicules present; 2; free; membranous; glabrous; toothed. Stamens 2–3. Anthers not penicillate. Ovary apically glabrous. Styles free to their bases. Stigmas 2.

Fruit, embryo and seedling. Fruit small; compressed laterally. Hilum short. Embryo not waisted. Endosperm containing compound starch grains. Embryo with an epiblast.

Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae absent. Long-cells of similar wall thickness costally and intercostally. Mid-intercostal long-cells fusiform; having straight or only gently undulating walls. Microhairs absent. Stomata absent or very rare. Subsidiaries parallel-sided. Intercostal short-cells absent or very rare. Costal silica bodies predominantly horizontally-elongated smooth, or horizontally-elongated crenate/sinuous; not sharp-pointed.

Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll with non-radiate chlorenchyma. Leaf blade adaxially flat. Midrib conspicuous; with one bundle only. All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present; forming ‘figures’. Sclerenchyma all associated with vascular bundles.

Cytology. Chromosome base number, x = 7. 2n = 28.

Classification. Watson & Dallwitz (1994): Pooideae; Poodae; Poeae. Soreng et al. (2015): Pooideae; Poodae; Poeae; Poinae. 2 species.

Distribution, phytogeography, ecology. New Zealand.

Species of open habitats. Grassland.

References, etc. Leaf anatomical: this project.

Illustrations. • S. laxa: Cheeseman (1914), Ill. of New Zealand Flora


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Cite this publication as: ‘Watson, L., Macfarlane, T.D., and Dallwitz, M.J. 1992 onwards. The grass genera of the world: descriptions, illustrations, identification, and information retrieval; including synonyms, morphology, anatomy, physiology, phytochemistry, cytology, classification, pathogens, world and local distribution, and references. Version: 13th November 2017. delta-intkey.com/grass’.

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