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The grass genera of the world

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

Kengia Packer

~ Diplachne

Including Cleistogenes Keng, Moliniopsis Gand.

Habit, vegetative morphology. Perennial. Culms 10–100 cm high; herbaceous; unbranched above (usually so in species referred to Cleistogenes). Plants unarmed. Leaves not basally aggregated. Leaf blades linear-lanceolate; narrow; flat, or rolled (convolute); without abaxial multicellular glands; without cross venation. Ligule a fringed membrane to a fringe of hairs.

Reproductive organization. Plants bisexual, all with bisexual spikelets; with hermaphrodite florets; exposed-cleistogamous, or chasmogamous; with hidden cleistogenes. The hidden cleistogenes in the leaf sheaths (especially associated with the upper leaves).

Inflorescence. Inflorescence many spikeleted; of spicate main branches (of loose racemes on a central axis), or paniculate; open to contracted; espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelets not secund; pedicellate; not imbricate.

Female-fertile spikelets. Spikelets 4–13 mm long; compressed laterally; disarticulating above the glumes; disarticulating between the florets; with distinctly elongated rachilla internodes between the florets. Rachilla prolonged beyond the uppermost female-fertile floret; the rachilla extension with incomplete florets. Hairy callus present. Callus blunt.

Glumes two; very unequal; shorter than the spikelets; shorter than the adjacent lemmas; pointed to not pointed; awnless; similar (membranous). Lower glume 1 nerved, or 3–5 nerved (at base). Upper glume 1 nerved, or 3–5(–7) nerved (at base). Spikelets with incomplete florets. The incomplete florets distal to the female-fertile florets. The distal incomplete florets merely underdeveloped; awnless.

Female-fertile florets 2–6 (to many?). Lemmas not becoming indurated; usually incised; minutely 2 lobed; not deeply cleft (two-toothed); mucronate to awned. Awns 1; median; from a sinus; non-geniculate. Lemmas hairy (pilose along margins), or hairless; carinate; 3 nerved, or 5(–7) nerved. Palea present; relatively long; apically notched (two-toothed); awnless, without apical setae; textured like the lemma; not indurated; 2-nerved; 2-keeled. Lodicules absent (usually, most florets being cleistogamous). Stamens 3. Anthers 0.7–3.5 mm long.

Fruit, embryo and seedling. Fruit free from both lemma and palea. Hilum short. Embryo large. Endosperm hard; without lipid. Embryo with an epiblast; with a scutellar tail; with an elongated mesocotyl internode. Embryonic leaf margins meeting.

Abaxial leaf blade epidermis. Papillae present; costal and intercostal. Intercostal papillae consisting of one oblique swelling per cell. Mid-intercostal long-cells rectangular. Microhairs present; elongated; clearly two-celled; chloridoid-type. Microhair apical cell wall of similar thickness/rigidity to that of the basal cell. Microhair basal cells 21–27 microns long. Microhair total length/width at septum 2.2. Microhair apical cell/total length ratio 0.3. Stomata common. Intercostal short-cells not paired; silicified. Intercostal silica bodies present and perfectly developed (but blurred by papillae); rounded, tall-and-narrow, and oryzoid-type. Costal short-cells conspicuously in long rows. Costal silica bodies present in alternate cell files of the costal zones; ‘panicoid-type’.

Transverse section of leaf blade, physiology. Lamina mid-zone in transverse section open.

C4; XyMS+. PCR sheaths of the primary vascular bundles interrupted; interrupted both abaxially and adaxially. PCR sheath extensions present. Maximum number of extension cells 2. Mesophyll not traversed by colourless columns. Leaf blade with distinct, prominent adaxial ribs to adaxially flat. Midrib not readily distinguishable; with one bundle only; without colourless mesophyll adaxially, or with colourless mesophyll adaxially (at least, sometimes with a few colourless cells between the bundles and the sclerenchyma). Bulliforms present in discrete, regular adaxial groups. All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders absent. Sclerenchyma all associated with vascular bundles. The lamina margins with fibres.

Cytology. Chromosome base number, x = 10. 2n = 40. 4 ploid. Chromosomes ‘small’.

Classification. Watson & Dallwitz (1994): Chloridoideae; main chloridoid assemblage. Soreng et al. (2015): Chloridoideae; Cynodonteae. 10 species.

Distribution, phytogeography, ecology. Temperate Eurasia.

Mesophytic, or xerophytic (mainly); species of open habitats; glycophytic.

Rusts and smuts. Rusts — Puccinia.

References, etc. Leaf anatomical: Van den Borre 1994; studied by us - K. serotina (L.) Packer (subsp. serotina), ‘Moliniopsis japonica Hayata’.

Illustrations. • K. squarrosa, as Molinia: Ledebour (1831), Icones Pl. novarum III

We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, distributions of character states within any set of taxa, geographical distribution, and classifications. See also Guidelines for using data taken from Web publications.

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: 11th December 2017.’.