Grass Genera of the World

L. Watson and M. J. Dallwitz


Sesleriella Deyl

Sometimes referred to Sesleria

Habit, vegetative morphology. Perennial; caespitose. Culms 5–15 cm high; herbaceous. Leaves non-auriculate. Sheath margins free. Leaf blades narrow; 1–2 mm wide; sagittate (e.g. S. appendiculata), or not cordate, not sagittate; not setaceous (convolute or flat); flat, or rolled (convolute); without cross venation; an unfringed membrane; not truncate; 0.5 mm long.

Reproductive organization. Plants bisexual, with bisexual spikelets; with hermaphrodite florets. The spikelets of sexually distinct forms on the same plant; hermaphrodite and sterile (the sterile spikelets reduced to bractlike scales at the base of the inflorescence); overtly heteromorphic.

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

Female-sterile spikelets. The sterile spikelets vestigial, represented by bracts at the base of the inflorescence.

Female-fertile spikelets. Spikelets compressed laterally; disarticulating above the glumes. Rachilla prolonged beyond the uppermost female-fertile floret; the rachilla extension with incomplete florets.

Glumes two; more or less equal; shorter than the adjacent lemmas, or long relative to the adjacent lemmas; pointed; shortly awned, or awnless (then mucronate); carinate; similar (ovate, membranous). Lower glume 1 nerved. Upper glume 1 nerved. Spikelets with incomplete florets. The incomplete florets distal to the female-fertile florets. Spikelets without proximal incomplete florets.

Female-fertile florets 3–4. Lemmas decidedly firmer than the glumes (silvery or grey); not becoming indurated; incised; not deeply cleft (toothed); awnless, or mucronate (the teeth shortly aristulate); hairy (proximally); carinate; without a germination flap; 5 nerved. Palea present; relatively long; 2-nerved; 2-keeled. Lodicules present; 2; free; membranous; glabrous; toothed; not or scarcely vascularized. Stamens 3. Ovary glabrous; without a conspicuous apical appendage. Styles fused. Stigmas 2.

Fruit, embryo and seedling. Fruit small (about 1.5 mm long). Embryo small.

Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae absent. Long-cells costal long-cells smaller; of similar wall thickness costally and intercostally. Mid-intercostal long-cells rectangular; having markedly sinuous walls (and pitted). Microhairs absent. Stomata absent or very rare. Intercostal short-cells common; in cork/silica-cell pairs (and solitary); silicified (a few only), or not silicified. Costal short-cells neither distinctly grouped into long rows nor predominantly paired (many paired). Costal silica bodies horizontally-elongated crenate/sinuous (often short), or rounded (often irregular, integrading with the sinuous/crenate forms); not sharp-pointed.

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 conspicuous (by the larger bundle); with one bundle only. Bulliforms not present in discrete, regular adaxial groups (bulliforms not apparent). All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present; forming ‘figures’ (I’s). Sclerenchyma all associated with vascular bundles.

Cytology. Chromosome base number, x = 7.

Taxonomy. Pooideae; Poodae; Seslerieae.

Distribution, ecology, phytogeography. 2 species; central and southern Europe.

Holarctic. Boreal and Tethyan. Euro-Siberian. Mediterranean. European.

References, etc. Leaf anatomical: this project.


Cite this publication as: Watson, L., and Dallwitz, M. J. (1992 onwards). ‘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.’ http://biodiversity.uno.edu/delta/. Version: 18th August 1999. Dallwitz (1980), Dallwitz, Paine and Zurcher (1993 onwards, 1998), and Watson and Dallwitz (1994), and Watson, Dallwitz, and Johnston (1986) should also be cited (see References).

Index