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The grass genera of the world

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

Joycea H.P. Linder

Named in honour of Joyce Vickery, a very productive agostologist from Sydney.

~ Chionochloa, Danthonia sensu lato, Notodanthonia, Rytidosperma

Type species: Type: J. pallida (R.Br.) H.P.Linder.

Habit, vegetative morphology. Perennial; rhizomatous, or caespitose. The flowering culms leafless. Culms 25–160 cm high; cylindrical; unbranched above; 2–4 noded. Culm nodes exposed; glabrous. Culm internodes solid. Young shoots intravaginal. Leaves mostly basal; non-auriculate; without auricular setae. Leaf blades linear-lanceolate; neither leathery nor flimsy; narrow; 3–20 mm wide; flat; without abaxial multicellular glands; not pseudopetiolate; without cross venation; persistent. Ligule a fringe of hairs; not truncate. Contra-ligule absent.

Reproductive organization. Plants bisexual, all with bisexual spikelets; with hermaphrodite florets. The spikelets all alike in sexuality; hermaphrodite.

Inflorescence. Inflorescence many spikeleted; paniculate; open; more or less irregular; non-digitate; espatheate. Spikelet-bearing axes persistent. Spikelets solitary; not secund; not two-ranked; pedicellate; not imbricate; not in distinct ‘long-and-short’ combinations.

Female-fertile spikelets. Spikelets morphologically ‘conventional’; 9–25 mm long; cuneate; green to purplish; compressed laterally; disarticulating above the glumes; disarticulating between the florets; with conventional internode spacings. The upper floret not stipitate. Rachilla prolonged beyond the uppermost female-fertile floret; hairless; the rachilla extension with incomplete florets. Hairy callus present. The callus hairs white. Callus short (slightly shorter than the rhachilla); blunt.

Glumes two; more or less equal; about equalling the spikelets; long relative to the adjacent lemmas; hairless; scabrous; pointed; not subulate; awnless; carinate; without a median keel-wing; similar. Lower glume much exceeding the lowest lemma; relatively smooth; 1–7 nerved. Upper glume 1–7 nerved. Spikelets with incomplete florets. The incomplete florets distal to the female-fertile florets. The distal incomplete florets merely underdeveloped; awnless. Spikelets without proximal incomplete florets.

Female-fertile florets 3–6. Lemmas deeply bilobed, the lobes tapering into apical setae; not convolute; not saccate; similar in texture to the glumes; smooth, or striate; not becoming indurated; white in fruit; incised; 2 lobed; deeply cleft; awned. Awns 1, or 3; if solitary median, or median and lateral (if three); if three different in form from the laterals; from a sinus; geniculate; hairless; much longer than the body of the lemma; entered by several veins; persistent. Awn bases twisted; flattened. Lemmas hairy (scattered on the lower half of the lemma backs). The hairs not in tufts (or scarcely so); not in transverse rows. Lemmas non-carinate; without a germination flap; 9 nerved; with the nerves confluent towards the tip. Palea present; relatively long; not convolute; tightly clasped by the lemma; apically notched; awnless, without apical setae; thinner than the lemma; not indurated; 2-nerved; 2-keeled. Palea back glabrous, or hairy. Palea keels wingless; scabrous, or hairy. Lodicules present; 2; free; fleshy; ciliate; not or scarcely vascularized. Stamens 3. Anthers 1.2–5.2 mm long. Ovary apically glabrous. Styles free to their bases; free. Style bases widely separated. Stigmas 2; red pigmented.

Fruit, embryo and seedling. Disseminule a caryopsis enclosed in but free of the lemma and palea. Fruit free from both lemma and palea; small; brown; fusiform (obovate); not grooved; compressed dorsiventrally; glabrous; smooth. Hilum short (linear to ovate, almost half as long as fruit). Pericarp thin; fused. Embryo large; waisted.

Ovule, embryology. Micropyle not noticeably oblique. Outer integument more than two cells thick at the micropylar margin. Inner integument discontinuous distally; not thickened around the micropyle. Synergids haustorial (strongly developed); exhibiting large, globular starch grains.

Transverse section of leaf blade, physiology. C3; XyMS+. Sclerenchyma all associated with vascular bundles (J. pallida).

Cytology. Chromosome base number, x = 6. 2n = 12. 4 ploid, or 6 ploid, or 8 ploid.

Classification. Watson & Dallwitz (1994): Arundinoideae; Danthonieae. Soreng et al. (2015): cf. Danthonioideae; Danthonieae. 3 species.

Distribution, phytogeography, ecology. Australia.

Not commonly adventive. Mesophytic; species of open habitats (light shade); glycophytic. Gravelly soils.

References, etc. Morphological/taxonomic: This description first drafted by H.P. Linder 1997). Leaf anatomical: studied by us - J. pallida.

Illustrations. • J. pallida, abaxial epidermis of leaf blade: this project. • J. pallida, abaxial epidermis of leaf blade with short-cell pairs: this project. • J. pallida, TS leaf blade: this project. • J. pallida, TS 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: 11th December 2017.’.