| # The grass genera of the world |

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

### Monachather Steud.

From the Greek monarchos (solitary) and ather (spike as in an ear of wheat), referring to the solitary white-like spike.

~ Danthonia sensu lato

Type species: Type: M. paradoxus Steud.

Habit, vegetative morphology. Perennial; caespitose. Culms 50–80 cm high; herbaceous; unbranched above; tuberous (the bases somewhat swollen, covered with scale-like sheaths bearing dense woolly hairs). Culm nodes glabrous. Leaves non-auriculate. Leaf blades narrow; 3–4 mm wide; flat; not pseudopetiolate; without cross venation; persistent. Ligule an unfringed membrane (jagged, often with dense marginal tufts of cilia); truncate; 1–3 mm long.

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

Inflorescence. Inflorescence few spikeleted; paniculate; contracted (linear, nearly racemose); espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent. Spikelets not secund; pedicellate; mostly not in distinct ‘long-and-short’ combinations (though sometimes there are few such pairs).

Female-fertile spikelets. Spikelets (8–)11–14(–17) mm long; compressed laterally; disarticulating above the glumes; disarticulating between the florets; with distinctly elongated rachilla internodes between the florets. Rachilla prolonged beyond the uppermost female-fertile floret; hairless (scabrid); the rachilla extension with incomplete florets. Hairy callus present (the hairs long). Callus short; blunt.

Glumes two; more or less equal; exceeding the spikelets; long relative to the adjacent lemmas (much exceeding them); hairless; glabrous; pointed; awnless; non-carinate; similar (papery). Lower glume 13–19 nerved. Upper glume 11–13 nerved. Spikelets with incomplete florets. The incomplete florets distal to the female-fertile florets.

Female-fertile florets (3–)5–6(–8). Lemmas decidedly firmer than the glumes; not becoming indurated; incised; 2 lobed; deeply cleft; awned. Awns 1; median; from a sinus (from between the long, glabrous lemma lobes); geniculate; much shorter than the body of the lemma to about as long as the body of the lemma. Lemmas hairy. The hairs in transverse rows (one row basal, one row beneath the lobes). Lemmas non-carinate; with a clear germination flap; 9–13 nerved. Palea present (becoming hard and shining, bent across the fruit); relatively long (longer than body of lemma); entire (obtuse or truncate), or apically notched (emarginate); awnless, without apical setae; leathery; indurated; 2-nerved; 2-keeled. Palea keels winged; hairy (ciliate). Lodicules present; 2; free; fleshy; glabrous; not or scarcely vascularized. Stamens 3. Anthers about 0.3 mm long; not penicillate; without an apically prolonged connective. Ovary apically glabrous. Styles free to their bases. Stigmas 2.

Fruit, embryo and seedling. Fruit free from both lemma and palea; small (1–2 mm long); longitudinally grooved (depressed beneath the palea margins, concave along the hilum face); compressed dorsiventrally. Hilum short. Embryo large; waisted. Endosperm hard.

First seedling leaf with a well-developed lamina. The lamina broad; curved; 11 veined.

Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae absent. Long-cells similar in shape costally and intercostally; differing markedly in wall thickness costally and intercostally. Mid-intercostal long-cells rectangular; having markedly sinuous walls. Microhairs present; panicoid-type; (40.5–)45–60(–66) microns long; (6.6–)8.1–9(–12) microns wide at the septum. Microhair total length/width at septum 5–9.1. Microhair apical cells 16.5–25.5(–28.5) microns long. Microhair apical cell/total length ratio 0.36–0.48. Stomata common; 31.5–36 microns long. Subsidiaries dome-shaped to triangular, or parallel-sided (by varying degrees of truncation of the apices of ‘triangles’); including both triangular and parallel-sided forms on the same leaf (and a variety of domes). Guard-cells overlapping to flush with the interstomatals. Intercostal short-cells absent or very rare. Costal short-cells predominantly paired. Costal silica bodies ‘panicoid-type’; mostly cross shaped, butterfly shaped, and dumb-bell shaped; not sharp-pointed.

Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll with non-radiate chlorenchyma. Leaf blade ‘nodular’ in section; with the ribs more or less constant in size. Midrib not readily distinguishable; with one bundle only. Bulliforms present in discrete, regular adaxial groups to not present in discrete, regular adaxial groups (mostly Ammophila-type arrangements of small cells, in the bases of the furrows); in places, inconspicuously in simple fans. All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present; forming ‘figures’. Sclerenchyma all associated with vascular bundles.

Cytology. Chromosome base number, x = 6. 2n = 72. 12 ploid.

Classification. Watson & Dallwitz (1994): Arundinoideae; Danthonieae (but with several eu-panicoid features!). Soreng et al. (2015): Arundinoideae; Arundineae. 1 species (M. paradoxa).

Distribution, phytogeography, ecology. Australia.

Xerophytic; species of open habitats. Arid grassland.

Economic aspects. Important native pasture species: M. paradoxa, in dry places.

References, etc. Morphological/taxonomic: Blake 1972a; Vickery 1956. Leaf anatomical: studied by us.

Illustrations. • Monachather paradoxa: Gardner, 1952. • Germination details in M. paradoxa. Monachather paradoxa. Radicle emerging via germination flap. • Monachather, leaf blade T.S., fluorescence image.

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: 15th June 2025. delta-intkey.com’.

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