The grass genera of the world
~ Poa sensu lato
Type species: Type: A. littoralis (Labill.) E.B.Alexeev.
Including Festucella E. Alekseev, Hookerochloa E. Alekseev, Schedonorus Beauv.
Habit, vegetative morphology. Perennial; rhizomatous (1), or caespitose. Culms 30–92.5–180 cm high; herbaceous; unbranched above; 2–3 noded (2/2). Culm nodes exposed, or hidden by leaf sheaths (2); glabrous. Culm internodes hollow. Plants unarmed (1/1). Young shoots intravaginal. Leaves mostly basal; auriculate (1), or non-auriculate. Sheath margins joined (2), or free. Leaf blades not all greatly reduced; linear; apically cucullate, or apically flat; neither leathery nor flimsy; narrow; 0.5–3.066–6.8 mm wide; flat (1/2), or folded (2/2), or rolled (1/2), or acicular (1/2); without cross venation; persistent (2/2); rolled in bud (1/2), or once-folded in bud (2/2). Ligule an unfringed membrane; truncate (2/2), or not truncate (2/2); 0.2–3.05–6.8 mm long. Contra-ligule absent (2/2).
Reproductive organization. Plants bisexual, all with bisexual spikelets; with hermaphrodite florets.
Inflorescence. Inflorescence paniculate; open, or contracted (1); spicate (1/1). Primary inflorescence branches inserted all around the main axis (1/1). Inflorescence espatheate; not comprising partial inflorescences and foliar organs. Spikelets not secund; pedicellate (2/2).
Female-fertile spikelets. Spikelets 6.8–10.71–17 mm long; compressed laterally; disarticulating above the glumes; disarticulating between the florets; with conventional internode spacings (1/1). Rachilla prolonged beyond the uppermost female-fertile floret; hairy (2/2); the rachilla extension with incomplete florets (2), or naked (2). Hairy callus present, or absent (1). Callus short; blunt.
Glumes two; very unequal (1), or more or less equal; shorter than the spikelets, or about equalling the spikelets (1); shorter than the adjacent lemmas, or long relative to the adjacent lemmas (1); hairless (2/2); scabrous (1/1); pointed; awnless; carinate, or non-carinate (1); similar. Lower glume 1 nerved (1), or 3 nerved, or 5 nerved (1). Upper glume 3 nerved, or 5 nerved. Spikelets with female-fertile florets only (1), or 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 3–4–5. Lemmas similar in texture to the glumes, or decidedly firmer than the glumes (1); not becoming indurated; entire (2), or incised; 2 lobed (2/2); not deeply cleft; awnless (1), or mucronate (2), or awned. Awns 1 (2/2); median (2/2); from a sinus (2/2), or apical (1/2); non-geniculate (2/2); hairless (2/2); much shorter than the body of the lemma (2/2); entered by one vein (1/1). Lemmas hairless; scabrous (2/2); carinate; without a germination flap (2/2); 3–4 nerved (1), or 5 nerved, or 6 nerved (1), or 7 nerved (2), or 8 nerved (1); with the nerves confluent towards the tip (1/2), or with the nerves non-confluent (1/2). Palea present; relatively long; tightly clasped by the lemma (1/1); entire (2), or apically notched; awnless, without apical setae; textured like the lemma; not indurated; 2-nerved; 2-keeled. Palea back glabrous (2), or scabrous, or hairy (2). Palea keels wingless; scabrous (1), or hairy. Lodicules present; 2; free; membranous; ciliate, or glabrous (2); toothed, or not toothed (1); not or scarcely vascularized (2/2). Stamens 3. Anthers 3.4–4.7–7.2 mm long; not penicillate (2/2); without an apically prolonged connective (1/1). Ovary apically glabrous. Styles free to their bases. Stigmas 2; white.
Fruit, embryo and seedling. Fruit free from both lemma and palea; small (2), or medium sized (2); fusiform (1/2), or ellipsoid (2/2); longitudinally grooved; compressed dorsiventrally; glabrous (1/1). Hilum short. Pericarp fused. Embryo small; not waisted. Endosperm hard (2/2). Embryo with an epiblast (1/1).
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous (2), or lacking (1). Papillae absent. Long-cells similar in shape costally and intercostally (2), or markedly different in shape costally and intercostally (1); of similar wall thickness costally and intercostally (2/2). Mid-intercostal long-cells rectangular (1), or fusiform (2); having markedly sinuous walls. Microhairs absent. Stomata common (1), or absent or very rare (2); 45–49.5–54 microns long. Subsidiaries dome-shaped (1/1); not including both parallel-sided and triangular forms on the same leaf (2/2). Guard-cells overlapped by the interstomatals (1/1). Intercostal short-cells common (1/2), or absent or very rare (1/2); in cork/silica-cell pairs (1/2), or not paired (1/2); silicified (2/2), or not silicified (1/2). Intercostal silica bodies rounded (1/1), or crescentic (1/1). Costal zones with short-cells. Costal short-cells predominantly paired (1), or neither distinctly grouped into long rows nor predominantly paired (2). Costal silica bodies poorly developed (1/1), or absent (1/1); horizontally-elongated crenate/sinuous (1), or horizontally-elongated smooth (1), or rounded (1), or tall-and-narrow (1), or crescentic (1); not sharp-pointed (2/2).
Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll with non-radiate chlorenchyma; without adaxial palisade (2/2). Leaf blade adaxially flat (2/2). Midrib conspicuous; with one bundle only. Bulliforms not present in discrete, regular adaxial groups. All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present (2), or absent (1); forming figures (2/2). Sclerenchyma all associated with vascular bundles (2), or not all bundle-associated (1). The extra sclerenchyma in a continuous abaxial layer (1/1).
Special diagnostic feature. Female-fertile lemma not as in Lombardochloa (q.v.).
Classification. Watson & Dallwitz (1994): Pooideae; Poodae; Poeae. Soreng et al. (2015): Pooideae; Poodae; Poeae; Poinae (?). 4 species.
Distribution, phytogeography, ecology. Maritime extra-tropical Australasia (Austrofestuca sensu stricto) and eastern Australia.
Helophytic (2), or mesophytic (1), or xerophytic (1); species of open habitats (1/1); halophytic (1), or glycophytic (2).
Special comments. This description combines generic descriptions which are offered separately in this data set but merged in some recent treatments (see Jacobs (1990), Telopea 3, 601–603 for discussion). The figures in parentheses either reflect breakdown figures for the segregate genera (when the sensu lato version exhibits more than one character state), and/or that a character is unknown for one or more of the three seggregates. Illustrations. • A. (= Hookerochloa) hookeriana (as Festuca): Hooker, Fl. Tasmaniae (1860). • A. littoralis: Gardner, 1952. • A. littoralis, abaxial epidermis of leaf blade: this project
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’.