| # The grass genera of the world |

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

### Koeleria Pers.

Named for early German agrostologist, G.L.Koeler.

Type species: Type: K. gracilis Pers., nom. illeg..

Including Aegialina Schult., Aegialitis Trin., Airochloa Link, Brachystylus Dulac, Ktenosachne Steud., Leptophyllochloa Cald., Lophochloa Reichenb., Poarion Reichenb., Rostraria Trin., Wilhelmsia Koch

Excluding Avellinia, Parafestuca

Habit, vegetative morphology. Annual (Lophochloa, Rostraria), or perennial; caespitose (usually), or rhizomatous (rarely). Culms 5–120 cm high; herbaceous; where recorded, unbranched above; tuberous, or not tuberous. Culm nodes glabrous. Culm internodes hollow. Leaves non-auriculate. Sheath margins free. Leaf blades linear; apically cucullate; narrow; 0.5–6 mm wide; flat, or folded, or rolled (convolute); not pseudopetiolate; without cross venation; persistent. Ligule present; an unfringed membrane (sometimes puberulent and ciliolate); truncate, or not truncate.

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

Inflorescence. Inflorescence paniculate; contracted (not interrupted); more or less ovoid, or spicate; espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent. Spikelets not secund; pedicellate.

Female-fertile spikelets. Spikelets (2.7–)4–7 mm long; compressed laterally; disarticulating above the glumes; disarticulating between the florets. Rachilla prolonged beyond the uppermost female-fertile floret; hairy, or hairless. Hairy callus present, or absent. Callus short.

Glumes two; very unequal, or more or less equal; shorter than the spikelets, or about equalling the spikelets; shorter than the adjacent lemmas (rarely), or long relative to the adjacent lemmas (the G2 usually equalling the first lemma); pointed; awnless; carinate; very dissimilar (sometimes, e.g. K. pumila), or similar. Lower glume 1–3 nerved. Upper glume 3 nerved, or 5 nerved. Spikelets with female-fertile florets only, or with incomplete florets. The incomplete florets distal to the female-fertile florets.

Female-fertile florets 2–4. Lemmas similar in texture to the glumes; not becoming indurated; entire (usually), or incised (e.g. in Lophochloa); blunt; awnless, or mucronate, or awned (but then the awns relatively inconspicuous, by contrast with Trisetum). Awns 1; median; from a sinus, or dorsal; from near the top; non-geniculate; much shorter than the body of the lemma to about as long as the body of the lemma; entered by one vein. Lemmas hairy, or hairless; carinate; 3–5 nerved. Palea present; relatively long (usually), or conspicuous but relatively short (e.g. K. cristata, K. pumila); gaping; apically notched; thinner than the lemma (hyaline or membranous); not indurated; 2-nerved; 2-keeled. Lodicules present; 2; free; membranous; glabrous; toothed. Stamens 3. Anthers 0.3–0.7 mm long (Rostraria), or 1.3–3 mm long; not penicillate. Ovary apically glabrous; without a conspicuous apical appendage. Styles free to their bases. Stigmas 2.

Fruit, embryo and seedling. Fruit small; slightly compressed laterally. Hilum short, or long-linear. Embryo small; not waisted. Endosperm liquid in the mature fruit; with lipid; containing compound starch grains. Embryo with an epiblast; without a scutellar tail; with a negligible mesocotyl internode. Embryonic leaf margins meeting.

Seedling with a short mesocotyl, or with a long mesocotyl; with a tight coleoptile. First seedling leaf with a well-developed lamina. The lamina narrow; erect; 3 veined.

Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae absent. Long-cells similar in shape costally and intercostally, or markedly different in shape costally and intercostally; of similar wall thickness costally and intercostally (thin walled). Intercostal zones with typical long-cells, or exhibiting many atypical long-cells. Mid-intercostal long-cells fusiform; having straight or only gently undulating walls. Microhairs absent. Stomata absent or very rare, or common. Subsidiaries low dome-shaped, or parallel-sided. Guard-cells overlapped by the interstomatals. Intercostal short-cells absent or very rare; in cork/silica-cell pairs, or not paired (some solitaries, and abundant prickles); silicified (when paired), or not silicified. Costal short-cells neither distinctly grouped into long rows nor predominantly paired. Costal silica bodies horizontally-elongated crenate/sinuous to horizontally-elongated smooth, or rounded, or saddle shaped (occasionally).

Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll with non-radiate chlorenchyma. Leaf blade with distinct, prominent adaxial ribs, or ‘nodular’ in section; with the ribs more or less constant in size. Midrib not readily distinguishable; with one bundle only. Bulliforms present in discrete, regular adaxial groups (between the vascular bundles), or not present in discrete, regular adaxial groups (e.g. K. cristata, K. pumila); in simple fans. All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present; forming ‘figures’. Sclerenchyma all associated with vascular bundles.

Phytochemistry. Leaves without flavonoid sulphates (1 species).

Special diagnostic feature. Panicle dense, cylindrical, ovoid, not interrupted: awns if present straight, subterminal, inconspicuous in the inflorescence.

Cytology. Chromosome base number, x = 7. 2n = 14, 26, 28, 40, 42, 43, 56, 70, 84, 112, and 126. 2, 4, 6, 8, 10, 12, 16, and 18 ploid (and aneuploids). Chromosomes ‘large’.

Classification. Watson & Dallwitz (1994): Pooideae; Poodae; Aveneae. Soreng et al. (2015): Pooideae; Poodae; Poeae (involving numerous synonyms); Aveninae. About 60 species.

Distribution, phytogeography, ecology. North and south temperate.

Pampas, Andean, and Fernandezian.

Commonly adventive. Mesophytic, or xerophytic; mostly species of open habitats. In dry grassland and rocky places.

Economic aspects. Significant weed species: K. phleoides, K. pyramidata. Important native pasture species: e.g. K. cristata.

Hybrids. Intergeneric hybrids with Trisetum: ×Trisetokoeleria Tsvelev.

Rusts and smuts. Rusts — Puccinia. Taxonomically wide-ranging species: Puccinia graminis, Puccinia coronata, Puccinia striiformis, Puccinia poarum, Puccinia hordei, Puccinia recondita, and Puccinia monoica. Smuts from Tilletiaceae and from Ustilaginaceae. Tilletiaceae — Entyloma, Tilletia, and Urocystis. Ustilaginaceae — Ustilago.

References, etc. Leaf anatomical: Metcalfe 1960; studied by us - K. australiensis Domin.

Special comments. The taxonomic situation around Koeleria and Trisetum (involving Trisetaria, Graphephorum, Rostraria, Lophochloa and Peyritschia) is hopelessly unsatisfactory, and demands either a world monograph of the approximately 150 species involved, or critical assessment via extensive worldwide sampling and an adequate character list. This sensu lato version of Koeleria reflects the impossibility of preparing adequate descriptions for segregate genera, and is poorly separable from that of Trisetum.

Illustrations. • Spikelet of Koeleria australiense. • General aspect of Koeleria capensis: Gibbs Russell et al., 1990. • Koeleria cristata: Bor, Flora of Iraq (1968). • Koeleria cristata, general aspect: Eng. Bot. (1872). • General morphology of Koeleria cristata: Gardner. • Inflorescence of Koeleria cristata. • Spikelets of Koeleria cristata. • General aspect of Koeleria pumila. • Inflorescence of Koeleria pumila. • Spikelets of Koeleria pumila.

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: 15th June 2025. delta-intkey.com’.

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