The grass genera of the world

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L. Watson and M. J. Dallwitz

Amblyopyrum Eig

From the Greek amblus (blunt) and puros (wheat), perhaps alluding to spikes with blunt spikelets.

Sometimes referred to Aegilops

Habit, vegetative morphology. Annual. Culms herbaceous. Leaves auriculate, or non-auriculate. Leaf blades linear; narrow; 1.5–6 mm wide; usually flat; without cross venation. Ligule an unfringed membrane; truncate; 0.5 mm long.

Reproductive organization. Plants bisexual, with bisexual spikelets; with hermaphrodite florets. The spikelets of sexually distinct forms on the same plant, or all alike in sexuality; hermaphrodite, or hermaphrodite and sterile (rarely, sterile at the extremities of the inflorescence).

Inflorescence. Inflorescence a single spike (glabrous, linear, usually very long). Rachides hollowed. Spikelets all partially embedded in the rachis. Inflorescence espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes with substantial rachides; disarticulating; disarticulating at the joints. Spikelets solitary; not secund; distichous.

Female-fertile spikelets. Spikelets 8–15 mm long; compressed laterally; falling with the glumes. Rachilla prolonged beyond the uppermost female-fertile floret; the rachilla extension with incomplete florets. Callus very short; blunt.

Glumes two; more or less equal; long relative to the adjacent lemmas; lateral to the rachis; not pointed; not subulate; awnless; non-carinate; similar (trapezoid or rectangular). Lower glume 3–9 nerved. Upper glume 4–9 nerved. Spikelets with incomplete florets. The incomplete florets distal to the female-fertile florets. Spikelets without proximal incomplete florets.

Female-fertile florets 4–8. Lemmas less firm than the glumes; not becoming indurated; entire; blunt; awnless; hairy, or hairless; non-carinate; without a germination flap; 5 nerved; with the nerves non-confluent. Palea present; relatively long; 2-nerved; 2-keeled. Lodicules present; 2; free; membranous; ciliate; toothed, or not toothed; not or scarcely vascularized. Stamens 3. Anthers 3.5–4.8 mm long. Ovary hairy. Styles free to their bases. Stigmas 2.

Fruit, embryo and seedling. Fruit adhering to lemma and/or palea; small to medium sized (3.5–4 mm long); ellipsoid; shallowly longitudinally grooved; compressed dorsiventrally; with hairs confined to a terminal tuft. Hilum long-linear. Embryo large to small (to about 1/3 the caryposis length); with an epiblast.

Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae absent. Long-cells similar in shape costally and intercostally, or markedly different in shape costally and intercostally; of similar wall thickness costally and intercostally, or differing markedly in wall thickness costally and intercostally. Mid-intercostal long-cells rectangular (mostly); having straight or only gently undulating walls. Microhairs absent. Stomata common; 39–41 microns long. Subsidiaries parallel-sided and dome-shaped. Guard-cells overlapped by the interstomatals. Intercostal short-cells absent or very rare (a few, solitary, not silicified, near veins). Crown cells present. Costal short-cells neither distinctly grouped into long rows nor predominantly paired. Costal silica bodies horizontally-elongated crenate/sinuous (predominantly), or horizontally-elongated smooth (few).

Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll with non-radiate chlorenchyma. Bulliforms present in discrete, regular adaxial groups; in simple fans. Combined sclerenchyma girders present. Sclerenchyma all associated with vascular bundles.

Cytology. Chromosome base number, x = 7. 2n = 14. 2 ploid. Haplomic genome content Z.

Taxonomy. Pooideae; Triticodae; Triticeae.

Distribution, ecology, phytogeography. 1 species; W. Asia.

Holarctic. Boreal and Tethyan. Euro-Siberian. Mediterranean and Irano-Turanian. European.

References, etc. Morphological/taxonomic: Löve 1984. Leaf anatomical: this project.

Illustrations. • A. muticum: Fl. Iraq, 1968. • Abaxial epidermis of leaf blade (A. muticum). • Abaxial epidermis of leaf blade (A. muticum). Amblyopyrum muticum. Showing ‘crown cells’.

The descriptions are offered for casual browsing only. We strongly advise against extracting comparative information from them. 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 or lacking specified attributes, distributions of character states within any set of taxa, geographical distribution, genera included in each family, and classifications (Dahlgren; Dahlgren, Clifford, and Yeo; Cronquist; APG).

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: 7th December 2015.’.