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The grass genera of the world

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

Saxipoa Soreng, L.J. Gillespie & S.W.L. Jacobs

~ Poa saxicola R. Br.

Type species: S. saxicola (R.Br.) Soreng, L.J., Gillespie & S.W.L. Jacobs.

Habit, vegetative morphology. Perennial; erect caespitose. Culms 13–105 cm high; herbaceous; unbranched above; 1–2 noded. Culm nodes glabrous. Culm internodes hollow. Young shoots intravaginal, or extravaginal and intravaginal. The shoots not aromatic. Leaves mostly basal; non-auriculate. Sheath margins joined basally 0–3% of their length. Leaf blades linear; shallowly naviculate or apically cucullate; narrow; 4–18 cm long, 3–5 mm wide; shallowly keeled, apically naviculate, flat, or folded; without cross venation. Ligule an unfringed membrane (ciliolate, abaxially hairy, lacerate or not); 0.9–4.5 mm long.

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

Inflorescence. Inflorescence exserted. paniculate; contracted; symmetrical, more or less ovoid to spicate (linear-oblong, 10–18 cm long). Primary inflorescence branches inserted all around the main axis (spiralled). Rachides flattened, or neither flattened nor hollowed, not winged (straplike or subterete). Spikelets solitary; not secund; pedicellate.

Female-fertile spikelets. Spikelets 4.5–6.8 mm long; broadly elliptic; turgid, slightly compressed laterally; disarticulating above the glumes; disarticulating between the florets. Rachilla prolonged beyond the uppermost female-fertile floret; the rachilla extension with incomplete florets, or naked. Hairy callus present (sometimes with a few straight hairs ventrally), or absent. Callus 0.27–0.33 mm long; blunt.

Glumes two; more or less equal; shorter than the spikelets; somewhat shorter than the adjacent lemmas; hairy to hairless (the margins ciliate below); pointed; acute, muticous awnless; carinate; narrowly ovate to elliptic, membranous to chartaceous, similar. Lower glume slightly shorter than the lowest lemma; 3 nerved, or 5 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; awnless.

Female-fertile florets 2–4. Lemmas ovate; membranous to chartaceous, similar in texture to the glumes to decidedly firmer than the glumes; not becoming indurated; entire; pointed to blunt; awnless to mucronate, or awned (the keel vein sometimes with a very short, straight awn or mucro not exceeding the lemma tip). Awns if so interpreted, 1; median; dorsal; from near the top; non-geniculate; much shorter than the body of the lemma; entered by one vein. Lemmas hairy (towards the apex of the mid-vein), or hairless; carinate; without a germination flap; 5 nerved, or 7 nerved; with the nerves non-confluent. Palea present; relatively long (slightly shorter than the lemma); tightly clasped by the lemma; acute to truncate, entire; awnless, without apical setae; textured like the lemma; not indurated; 2-nerved; longitudinally infolded or 2-keeled. Palea back glabrous to scabrous (or puberulous). Lodicules present; 2; free; membranous; ciliate to glabrous (with or without a few apical cilia); toothed to not toothed; not or scarcely vascularized. Stamens 3. Anthers 1–1.5 mm long; not penicillate; without an apically prolonged connective. Ovary obovoid, apically glabrous (or with no more than a few apical cilia); without a conspicuous apical appendage. Styles 2, free to their bases; free. Stigmas 2; densely plumose, without secondary branching, white.

Fruit, embryo and seedling. Fruit free from both lemma and palea; small (2.1–2.6 mm long); fusiform, or ellipsoid; ventrally longitudinally grooved; compressed laterally, or compressed dorsiventrally (or ventrally); glabrous. Hilum short. Embryo large; not waisted. Endosperm hard. Embryo with an epiblast.

Classification. Watson & Dallwitz (1994): not described separately. Soreng et al. (2015): Pooideae; Poodae; Poeae; Poinae. 1 species (S. saxicola).

Distribution, phytogeography, ecology. Southeastern Australia, Tasmania.

References, etc. Morphological/taxonomic: Vickery (1970), Weiller et al. (1995).

Illustrations. • P. tenera and S. saxicola (as Poa): 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.’.