The grass genera of the world
~ Agrostis (A. juressi Link)
Habit, vegetative morphology. Perennial; stoloniferous. Culms 40–80 cm high; herbaceous; unbranched above; 2–4 noded. Culm nodes exposed. Culm leaves present. Young shoots intravaginal. Leaves not basally aggregated; non-auriculate. Sheath margins free. Leaf blades linear to lanceolate; narrow; (4–)5–8(–10) mm wide (4–15 cm long); flat; not pseudopetiolate; without cross venation; persistent. Ligule an unfringed membrane; truncate; 0.2–0.5 mm long.
Reproductive organization. Plants bisexual, all with bisexual spikelets; with hermaphrodite florets. The spikelets hermaphrodite.
Inflorescence. Inflorescence paniculate; contracted (with short, erect branches); spicate (interrupted); espatheate; not comprising partial inflorescences and foliar organs. Spikelet-bearing axes persistent. Spikelets not secund; pedicellate (the pedicels much shorter than the spikelets, not clavate); imbricate.
Female-fertile spikelets. Spikelets 2.5–3.2 mm long; compressed laterally; disarticulating above the glumes. Hairy callus absent. Callus glabrous.
Glumes two; more or less equal; about equalling the spikelets to exceeding the spikelets; long relative to the adjacent lemmas (somewhat exceeding it); puberulent; not pointed; awnless; carinate; similar (herbaceous, lanceolate). Lower glume 1 nerved. Upper glume 1 nerved. Spikelets with female-fertile florets only; without proximal incomplete florets.
Female-fertile florets 1. Lemmas similar in texture to the glumes (leathery, green); not becoming indurated; entire to incised; more or less linear, narrowed above; not deeply cleft (obtuse, truncate or denticulate); awnless to mucronate; hairless; non-carinate; without a germination flap; 5 nerved; with the nerves non-confluent. Palea present; conspicuous but relatively short to very reduced (no more than 1/5 the lemma length); tightly clasped by the lemma; apically notched; awnless, without apical setae. Lodicules present; 2; free; membranous (falcate); glabrous. Stamens 3. Anthers about 1.2 mm long. Ovary apically glabrous. Stigmas 2; white.
Fruit, embryo and seedling. Fruit small (about 1.5 mm long); ellipsoid; longitudinally grooved; compressed dorsiventrally. Hilum short. Embryo small.
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae absent. Intercostal zones with typical long-cells. Mid-intercostal long-cells fusiform; having straight or only gently undulating walls. Microhairs absent. Stomata common. Costal silica bodies horizontally-elongated crenate/sinuous (?).
Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll not Isachne-type; not traversed by colourless columns. Leaf blade adaxially flat. Midrib not readily distinguishable; with one bundle only; without colourless mesophyll adaxially. Bulliforms present in discrete, regular adaxial groups; in simple fans. Combined sclerenchyma girders present. Sclerenchyma all associated with vascular bundles.
Cytology. Chromosome base number, x = 7. 2n = 14.
Classification. Watson & Dallwitz (1994): Pooideae; Poodae; Aveneae. Soreng et al. (2015): cf. Pooideae (as a synonym?); Poodae; Poeae; cf. Agrostidinae. 1 species.
Distribution, phytogeography, ecology. Iberian Peninsula and northeast Africa.
Mesophytic; shade species; glycophytic. In damp, shady places.
References, etc. Morphological/taxonomic: Garcia, Blanca and Torres 1987. Leaf anatomical: Garcia, Blanca and Torres 1987.
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: 13th November 2017. delta-intkey.com/grass’.