The grass genera of the world

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

Festuca L.

Festuca: Latin (e.g. Pliny) for culm, stem or straw, also the name for a weed growing among barley.

Fescues.

Type species: Type: F. ovina L.

Including Amphigenes Janka, Anatherum Nabelek, Argillochloa Weber, Bucetum Parnell, Drymochloa Holub, Drymonaetes Fourr., Festucaria Fabric., Gnomonia Lunell, Gramen Krause, Hellerochloa Rauschert, Leiopoa Ohwi, Lojaconoa Gand., Nabelekia Roshev., Patzkea, Wasatchia M.E. Jones

Excluding Austrofestuca, Helleria, Leucopoa, Parafestuca, Pseudobromus, Tsvelevia

Habit, vegetative morphology. Perennial; rhizomatous, or stoloniferous, or caespitose, or decumbent. Culms 2–200 cm high; herbaceous; nearly always unbranched above, or branched above (e.g., F. multinodis); tuberous, or not tuberous. Culm nodes glabrous. Culm internodes solid, or hollow. Young shoots extravaginal, or intravaginal. Leaves mostly basal, or not basally aggregated; auriculate, or non-auriculate. Sheath margins joined, or free. Leaf blades linear to linear-lanceolate; apically cucullate; narrow; 0.2–15 mm wide; setaceous, or not setaceous; flat, or folded, or rolled (convolute or involute); not pseudopetiolate; without cross venation; persistent; rolled in bud, or once-folded in bud. Ligule an unfringed membrane (sometimes ciliolate); truncate; 0.1–1.5(–5.5) mm long (usually less than 1 mm).

Reproductive organization. Plants bisexual, all with bisexual spikelets (Leucopoa being excluded); with hermaphrodite florets. The spikelets all alike in sexuality. Plants outbreeding and inbreeding (by cleistogamy); exposed-cleistogamous, or chasmogamous. Viviparous (sometimes), or not viviparous.

Inflorescence. Inflorescence paniculate; open (usually), or contracted (rarely); when contracted spicate, or more or less irregular; with capillary branchlets, or without capillary branchlets. Primary inflorescence branches borne biseriately on one side of the main axis, or borne distichously. Inflorescence espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent. Spikelets not secund; pedicellate.

Female-fertile spikelets. Spikelets 3–20 mm long; compressed laterally; disarticulating above the glumes; disarticulating between the florets. Rachilla prolonged beyond the uppermost female-fertile floret; hairy, or hairless; the rachilla extension with incomplete florets. Hairy callus absent.

Glumes two; very unequal; shorter than the spikelets; shorter than the adjacent lemmas; pointed; awnless; carinate to non-carinate; similar (usually narrow to ovate-lanceolate). Lower glume 1–3 nerved. Upper glume (1–)3–5 nerved. Spikelets with incomplete florets. The incomplete florets distal to the female-fertile florets. The distal incomplete florets merely underdeveloped. Spikelets without proximal incomplete florets.

Female-fertile florets 2–14 (rarely 1). Lemmas similar in texture to the glumes to decidedly firmer than the glumes; not becoming indurated; entire, or incised; when entire pointed, or blunt; when incised, not deeply cleft; awnless, or mucronate, or awned. Awns when present, 1; from a sinus, or apical; non-geniculate; much shorter than the body of the lemma (usually), or about as long as the body of the lemma (sometimes, rarely somewhat longer); entered by one vein. Lemmas hairy (rarely), or hairless; non-carinate; 3–7 nerved. Palea present; relatively long; tightly clasped by the lemma; apically notched; awnless, without apical setae; textured like the lemma; not indurated (submembranous); 2-nerved; 2-keeled. Lodicules present; 2; free; membranous; ciliate, or glabrous; toothed. Stamens 3. Anthers 0.4–6 mm long; not penicillate. Ovary apically glabrous, or apically hairy; without a conspicuous apical appendage. Styles free to their bases. Stigmas 2; white.

Fruit, embryo and seedling. Fruit adhering to lemma and/or palea, or free from both lemma and palea; small, or medium sized, or large; fusiform, or ellipsoid; longitudinally grooved; compressed dorsiventrally; with hairs confined to a terminal tuft. Hilum long-linear (usually about as long as the grain, but sometimes elliptical and only half as long). Embryo small; not waisted. Endosperm hard; without lipid; containing compound starch grains (mostly?), or containing only simple starch grains (e.g., F. paradoxa). Embryo with an epiblast; without a scutellar tail; with a negligible mesocotyl internode. Embryonic leaf margins meeting.

Seedling with a long mesocotyl; with a loose coleoptile, or with a tight coleoptile. First seedling leaf with a well-developed lamina. The lamina narrow; erect; 3–5 veined.

Ovule, embryology. Micropyle oblique. Outer integument extensive, being absent only from the micropylar region; two cells thick at the micropylar margin. Inner integument continuous, the micropyle constricted; thickened around the micropyle. Synergids not haustorial; without large, globular starch grains.

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. Mid-intercostal long-cells rectangular, or fusiform; having markedly sinuous walls (rarely almost straight). Microhairs absent. Stomata absent or very rare, or common; when stomata present, 39–51 microns long. Subsidiaries low dome-shaped, or parallel-sided, or parallel-sided and dome-shaped. Guard-cells overlapped by the interstomatals, or overlapping to flush with the interstomatals. Intercostal short-cells common; in cork/silica-cell pairs; silicified. Intercostal silica bodies rounded, or tall-and-narrow, or crescentic. Costal short-cells predominantly paired, or neither distinctly grouped into long rows nor predominantly paired. Costal silica bodies rounded (commonly), or tall-and-narrow, or crescentic, or horizontally-elongated crenate/sinuous (occasionally), or horizontally-elongated smooth (occasionally).

Transverse section of leaf blade, physiology. C₃; XyMS+. Mesophyll with non-radiate chlorenchyma. Leaf blade with distinct, prominent adaxial ribs, or adaxially flat; with the ribs more or less constant in size to with the ribs very irregular in sizes. Midrib conspicuous, or not readily distinguishable; with one bundle only. Bulliforms present in discrete, regular adaxial groups (usually, in the furrows), or not present in discrete, regular adaxial groups; usually in simple fans. Many of the smallest vascular bundles unaccompanied by sclerenchyma, or all the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present, or absent; forming ‘figures’, or nowhere forming ‘figures’. Sclerenchyma all associated with vascular bundles, or not all bundle-associated. The ‘extra’ sclerenchyma when present, in abaxial groups, or in a continuous abaxial layer (often).

Culm anatomy. Culm internode bundles in one or two rings.

Phytochemistry. Tissues of the culm bases with little or no starch. Fructosans predominantly short-chain. Leaves without flavonoid sulphates (4 species).

Cytology. Chromosome base number, x = 7. 2n = 14, 28, 35, 42, 56, and 70. 2, 4, 5, 6, 8, and 10 ploid. Chromosomes ‘large’. Haploid nuclear DNA content (1.5–)1.8–3.6 pg (13 species, mean 2.6 - the lowest values representing high polyploids). Mean diploid 2c DNA value 6.5 pg (9 species, 3.4–9.5).

Classification. Watson & Dallwitz (1994): Pooideae; Poodae; Poeae. Soreng et al. (2015): Pooideae; Poodae; Poeae; Loliinae. 360 species (or more).

Distribution, phytogeography, ecology. Worldwide temperate & mountains.

Commonly adventive. Helophytic (rarely), or mesophytic (mostly), or xerophytic (rarely); halophytic, or glycophytic. Hillsides, mountains, plains, meadows.

Economic aspects. Significant weed species: F. arundinacea, F. ovina, F. rubra, F. tenuifolia. Cultivated fodder: F. arundinacea, F. pratensis, F. rubra etc. (Fescues). Lawns and/or playing fields: several fine-leaved species - F. rubra, F. tenuifolia, F. ovina etc.

Hybrids. Intergeneric hybrids with Vulpia (×Festulpia Melderis ex Stace & R. Cotton), with Lolium (×Festulolium Aschers. & Graebn.) and supposedly with Bromus (×Bromofestuca Prodan. - Bull. Grad. Bot. Univ. Cluj 16, 93 (1936)).

Rusts and smuts. Rusts — Puccinia. Taxonomically wide-ranging species: Puccinia graminis, Puccinia coronata, Puccinia striiformis, Puccinia pygmaea, Puccinia brachypodii, Puccinia poarum, Puccinia recondita, ‘Uromyces’ turcomanicum, ‘Uromyces’ dactylidis, and ‘Uromyces’ hordeinus. Smuts from Tilletiaceae and from Ustilaginaceae. Tilletiaceae — Entyloma, Tilletia, and Urocystis. Ustilaginaceae — Ustilago.

References, etc. Morphological/taxonomic: Vickery 1939; Alekseev 1984. Leaf anatomical: Metcalfe 1960; Aiken et al. 1985; studied by us - F. arundinacea Schreb., F. asperula Vickery, Festuca leptopogon Stapf, Festuca rubra L.

Each slide with rabbit antiserum in the trough, Lolium perenne pollen extract (control) in the upper well, and comparable extracts from other genera in the lower wells, as indicated. Results are compared using raw extract (left) with those using boiled extract (right). Antigens allergenic in humans are concentrated in the heat-stable components. For experimental details and discussion of the taxonomic patterns among cross-reactions, see Watson and Knox (1976) and Watson (1983). • Grass pollen antigens: cross-reactions against anti-Lolium serum. IMMUNOELECTROPHRESIS OF GRASS POLLEN EXTRACTS (DIFFUSIBLE ANTIGENS).

Each slide with rabbit antiserum in the trough, Lolium perenne pollen extract (control) in the upper well, and comparable extracts from other genera in the lower wells, as indicated. For experimental details and discussion of the taxonomic patterns among cross-reactios, see Watson and Knox (1976) and Watson (1983). • Heat stable grass pollen antigens (allergens): cross-reactions against anti-Lolium serum. IMMUNOELECTROPHRESIS OF GRASS POLLEN EXTRACTS (DIFFUSIBLE ANTIGENS-HEAT-STABLE COMPONENT).

Each slide with rabbit antiserum in the trough, boiled Lolium perenne pollen extract (control) in the upper well, and comparable boiled extracts from other genera in the lower wells, as indicated. For experimental details and discussion of the taxonomic patterns among cross-reactios, see Watson and Knox (1976) and Watson (1983). • Grass pollen antigens: cross-reactions against anti-Cynodon serum. IMMUNOELECTROPHORESIS OF GRASS POLLEN EXTRACTS (DIFFUSIBLE ANTIGENS).

Each slide with rabbit antiserum in the trough, Cynodon dactylon pollen extract (control) in the upper well, and comparable extracts from other genera in the lower wells, as indicated. Results are compared using raw extract (left) with those using boiled extract (human allergens, right). For experimental details and discussion of the taxonomic patterns among cross-reactions, see Watson and Knox (1976) and Watson (1983). • Grass pollen antigens: cross-reactions against anti-Zea serum. IMMUNOELECTROPHORESIS OF GRASS POLLEN EXTRACTS (DIFFUSIBLE ANTIGENS).

Each slide with rabbit antiserum in the trough, Zea mays pollen extract (control) in the upper well, and comparable extracts from other genera in the lower wells, as indicated. Results are compared using raw extract (left) with those using boiled extract (where availabe, right). Antigens allergenic in humans are concentrated in the heat-stable components. For experimental details and discussion of the taxonomic patterns among cross-reactions, see Watson and Knox (1976) and Watson (1983). • Grass pollen antigens: cross-reactions against anti-Zea serum. • X Festulolium loliaceum (as Festuca pratensis var. loliacea), = F. pratensis x Lolium perenne: Eng. Bot. (1872).

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: 25th January 2024. delta-intkey.com’.

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