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The grass genera of the world

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

Homopholis C.E. Hubb.

Type species: Type: H. belsonii C.E.Hubb.

Habit, vegetative morphology. Perennial; stoloniferous (often), or caespitose. Culms 20–50 cm high; herbaceous. Culm nodes glabrous. Culm leaf sheaths rounded. Culm internodes hollow. Leaves not basally aggregated; non-auriculate. Leaf blades narrow; 2–2.5 mm wide; without cross venation; persistent; rolled in bud. Ligule an unfringed membrane; truncate; 1.5 mm long.

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

Inflorescence. Inflorescence paniculate; open (up to 25 cm long, the branches to 15 cm with one or few spikelets towards their ends); with capillary branchlets. Primary inflorescence branches inserted all around the main axis. Inflorescence espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent. Spikelets not secund. Pedicel apices cupuliform.

Female-fertile spikelets. Spikelets 4.5–6 mm long; lanceolate; compressed dorsiventrally; falling with the glumes. Rachilla terminated by a female-fertile floret. Hairy callus absent.

Glumes two; more or less equal (the G1 slightly longer); long relative to the adjacent lemmas; pointed; awnless; very dissimilar to similar (the upper shortly hairy on the back). Lower glume 3–7 nerved. Upper glume 7 nerved, or 9 nerved. Spikelets with incomplete florets. The incomplete florets proximal to the female-fertile florets. Spikelets with proximal incomplete florets. The proximal incomplete florets 1; paleate, or epaleate. Palea of the proximal incomplete florets (when present) reduced (nerveless). The proximal incomplete florets sterile. The proximal lemmas similar to G2; awnless; 7 nerved, or 9 nerved; decidedly exceeding the female-fertile lemmas; less firm than the female-fertile lemmas; not becoming indurated.

Female-fertile florets 1. Lemmas about half the spikelet length, shortly beaked; decidedly firmer than the glumes; smooth; becoming indurated (slightly so, and shiny); yellow in fruit; entire; pointed; awnless (but rostrate); hairless; non-carinate (rounded on the back); having the margins lying flat on the palea; with a clear germination flap; 5–7 nerved. Palea present (shortly auriculate at the base); relatively long; entire; awnless, without apical setae; thinner than the lemma (membranous); not indurated; 2-nerved. Lodicules present; 2; free; fleshy; glabrous. Stamens 3. Anthers 1.5 mm long; not penicillate. Ovary apically glabrous. Styles free to their bases. Stigmas 2; red pigmented.

Fruit, embryo and seedling. Fruit small; compressed dorsiventrally. Hilum short. Embryo large.

Abaxial leaf blade epidermis. Papillae absent (except on the subsidiaries). Mid-intercostal long-cells having markedly sinuous walls. Microhairs present; panicoid-type; 33–39 microns long; 13–17.4 microns wide at the septum. Microhair total length/width at septum 5–6.1. Microhair apical cells 5.4–7.2 microns long. Microhair apical cell/total length ratio 0.39–0.45. Stomata common; 29–33 microns long. Subsidiaries papillate; triangular. Costal silica bodies ‘panicoid-type’.

Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll with 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; in simple fans. All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present; forming ‘figures’. Sclerenchyma all associated with vascular bundles.

Classification. Watson & Dallwitz (1994): Panicoideae; Panicodae; Paniceae. Soreng et al. (2015): Panicoideae; Panicodae; Paniceae. 3 species.

Distribution, phytogeography, ecology. Australia.

Shade species; glycophytic. In forests.

Economic aspects. Important native pasture species: H. belsonii.

References, etc. Morphological/taxonomic: Hubbard 1934; Webster 1987. Leaf anatomical: studied by us - H. proluta (F. Muell.) R. Webster.

Illustrations. • H. proluta: Turner, Australian Grasses (1895). • H. proluta, abaxial epidermis of leaf blade: this project. • H. proluta, abaxial epidermis of leaf blade: this project. • H. proluta, TS 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: 11th December 2017.’.