The grass genera of the world
The grass genera of the world | |
Milium: old Latin name for millet.
Including Milearium Moench
Habit, vegetative morphology. Annual, or perennial; stoloniferous, or caespitose. Culms 10–180 cm high; herbaceous; unbranched above. Culm nodes glabrous. Culm internodes hollow. Young shoots extravaginal. Leaves non-auriculate. Leaf blades linear to linear-lanceolate; broad, or narrow; 2–18 mm wide; flat; not pseudopetiolate; without cross venation; persistent; rolled in bud. Ligule an unfringed membrane; not truncate; 4–5 mm long.
Reproductive organization. Plants bisexual, with bisexual spikelets; with hermaphrodite florets.
Inflorescence. Inflorescence paniculate; open; with capillary branchlets; espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent. Spikelets not secund; pedicellate.
Female-fertile spikelets. Spikelets 2–4 mm long; somewhat compressed dorsiventrally; disarticulating above the glumes. Rachilla terminated by a female-fertile floret. Hairy callus absent. Callus short; blunt.
Glumes two; more or less equal; about equalling the spikelets to exceeding the spikelets; long relative to the adjacent lemmas; free; pointed (acute); awnless; non-carinate; similar (membranous). Lower glume 3 nerved. Upper glume 3 nerved. Spikelets with female-fertile florets only; without proximal incomplete florets.
Female-fertile florets 1. Lemmas rounded; not convolute; decidedly firmer than the glumes (leathery); becoming indurated (shiny in fruit); entire; blunt; awnless; hairless; non-carinate; 5 nerved. Palea present; relatively long; entire; textured like the lemma (leathery); indurated; 2-nerved; keel-less. Lodicules present; 2; free; membranous; glabrous; toothed, or not toothed; not or scarcely vascularized. Stamens 3. Anthers 1.3–3 mm long; not penicillate. Ovary glabrous. Styles free to their bases. Stigmas 2; white.
Fruit, embryo and seedling. Fruit small (about 2 mm long); compressed dorsiventrally, or not noticeably compressed. Hilum short (1/5 to almost 1/2 grain length). Embryo small; not waisted. Endosperm hard; with lipid; containing compound starch grains. Embryo with an epiblast; without a scutellar tail; with a negligible mesocotyl internode. Embryonic leaf margins meeting.
Seedling with a long mesocotyl; with a loose coleoptile. First seedling leaf with a well-developed lamina. The lamina broad; erect; 3–5 veined.
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae absent. Long-cells markedly different in shape costally and intercostally (the costals narrower, rectangular); of similar wall thickness costally and intercostally (thin walled). Mid-intercostal long-cells fusiform; having straight or only gently undulating walls. Microhairs absent. Stomata common. Subsidiaries parallel-sided. Guard-cells overlapped by the interstomatals. Intercostal short-cells absent or very rare. Costal short-cells neither distinctly grouped into long rows nor predominantly paired. Costal silica bodies absent (in the material seen).
Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll with non-radiate chlorenchyma; without adaxial palisade. Leaf blade adaxially flat. Midrib conspicuous, or not readily distinguishable; with one bundle only; with colourless mesophyll adaxially, or without colourless mesophyll adaxially. Bulliforms present in discrete, regular adaxial groups (between the vascular bundles). All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present; forming ‘figures’.
Cytology. Chromosome base number, x = 4, 5, 7, and 9. 2n = 8, 10, 28, and 42. 2, 4, and 6 ploid. Chromosomes ‘large’.
Taxonomy. Pooideae; Poodae; Aveneae.
Distribution, ecology, phytogeography. 3–4 species; North temperate. Commonly adventive. Mesophytic and xerophytic; shade species and species of open habitats.
Holarctic. Boreal and Tethyan. Euro-Siberian, Eastern Asian, and Atlantic North American. Mediterranean and Irano-Turanian. European and Siberian. Canadian-Appalachian.
Rusts and smuts. Rusts — Puccinia. Taxonomically wide-ranging species: Puccinia graminis, Puccinia coronata, Puccinia striiformis, Puccinia brachypodii, Puccinia recondita, and ‘Uromyces’ dactylidis. Smuts from Tilletiaceae and from Ustilaginaceae. Tilletiaceae — Urocystis. Ustilaginaceae — Ustilago.
References, etc. Morphological/taxonomic: Macfarlane and Watson 1980. Leaf anatomical: this project.
This description is offered for casual browsing only. We strongly advise against extracting comparative information from it. This is much more easily achieved using 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 specified attributes, summaries of attributes within groups of taxa, geographical distribution, classification, and species sampled for anatomy.
Cite this publication as: ‘Watson, L., 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 February 2012. http://delta-intkey.com’.