The grass genera of the world

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

Hookerochloa E. Alekseev

~ Austrofestuca (Festuca) hookeriana

Habit, vegetative morphology. Perennial; caespitose. Culms 55–180 cm high; herbaceous; unbranched above; 2–3 noded. Culm nodes exposed, or hidden by leaf sheaths; glabrous. Culm internodes hollow. Young shoots intravaginal (in our material). Leaves mostly basal; non-auriculate. Sheath margins joined (to 2/3 of their length, in the lower leaves), or free (upper leaves). Sheaths terete, not splitting longitudinally into fibres. Leaf blades linear; apically cucullate; narrow; 3–6.8 mm wide (11–70 cm long); flat to folded; without cross venation; persistent; once-folded in bud. Ligule an unfringed membrane; truncate, or not truncate; 0.2–2.5 mm long (basal leaves), or 2.7–6.8 mm long (culm leaves). Contra-ligule absent.

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

Inflorescence. Inflorescence paniculate; open (diffuse); espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent. Spikelets not secund.

Female-fertile spikelets. Spikelets 7.7–14 mm long; compressed laterally; disarticulating above the glumes; disarticulating between the florets; with conventional internode spacings. Rachilla prolonged beyond the uppermost female-fertile floret; usually hairy; the rachilla extension naked. Hairy callus present. Callus short; blunt (densely villous).

Glumes two; very unequal to more or less equal; shorter than the spikelets; shorter than the adjacent lemmas; hairless; scabrous; pointed; awnless; carinate; similar (membranous, with thin margins). Lower glume 3 nerved. Upper glume 3 nerved, or 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 3–5. Lemmas lanceolate; similar in texture to the glumes (membranous to chartaceous); not becoming indurated; entire (usually), or incised; when incised, 2 lobed; not deeply cleft (sometimes minutely bidenticulate or erose); awned, or mucronate to awned (the lower lemmas usually conspicuously awned, the upper lemmas sometimes awnless). Awns 1; median; from a sinus, or apical (subapical); non-geniculate; hairless (scabrous); much shorter than the body of the lemma (0.2–3.4 mm long); entered by one vein. Lemmas hairless; scabrous (below); carinate; without a germination flap; 5–7 nerved; with the nerves confluent towards the tip. Palea present; relatively long; tightly clasped by the lemma; entire to apically notched; awnless, without apical setae; textured like the lemma; not indurated; 2-nerved; 2-keeled. Palea back glabrous, or scabrous. Palea keels wingless; hairy (densely puberulous). Lodicules present; 2; free; membranous; sparsely ciliate, or glabrous; toothed, or not toothed; not or scarcely vascularized. Stamens 3. Anthers 3.4–4.7 mm long; not penicillate; without an apically prolonged connective. Ovary apically glabrous. Styles free to their bases. Stigmas 2; white.

Fruit, embryo and seedling. Fruit free from both lemma and palea; small (2.6–3.4 mm long); ellipsoid; ventrally longitudinally grooved; compressed dorsiventrally; glabrous. Hilum short (oval). Embryo small; not waisted. Endosperm hard. Embryo with an epiblast.

Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae absent. Long-cells similar in shape costally and intercostally; of similar wall thickness costally and intercostally. Mid-intercostal long-cells rectangular; having markedly sinuous walls. Microhairs absent. Stomata common; 45–54 microns long. Subsidiaries mostly dome-shaped (but some truncated and approaching parallel-sided). Guard-cells overlapped by the interstomatals. Intercostal short-cells in cork/silica-cell pairs; silicified. Intercostal silica bodies irregularly rounded (potato shaped), or crescentic. With a few costal prickles. Crown cells absent. Costal short-cells neither distinctly grouped into long rows nor predominantly paired (mostly in pairs and short rows). Costal silica bodies rounded (predominating), or crescentic (a few, intergrading with the rounded forms).

Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll with non-radiate chlorenchyma; without adaxial palisade. Leaf blade adaxially flat. Midrib conspicuous (by its abaxial keel and flanking hinges); with one bundle only. Bulliforms not present in discrete, regular adaxial groups (save for the midrib ‘hinges’). All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present; forming ‘figures’ (with all the bundles). Sclerenchyma all associated with vascular bundles.

Classification. Watson & Dallwitz (1994): Pooideae; Poodae; Poeae. Soreng et al. (2015): Pooideae; Poodae; Poeae; Poinae. 1 species, or 2 species (? - H. hookeriana, and cf. Austrofestuca eriopoda).

Distribution, phytogeography, ecology. Eastern Australia.

Helophytic; glycophytic. Alpine and subalpine swamps.

References, etc. Morphological/taxonomic: Alekseev 1985; Jacobs 1990. Leaf anatomical: studied by us - H. hookeriana (F. Muell. ex Hook. f.) E. Alexeev.

Illustrations. • H. hookeriana (as Festuca): Hooker, Fl. Tasmaniae (1860)

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: 11th December 2017.’.