Eremopyrum (Ledeb.) Jaub. & Spach
From the Greek eremos (desert) and puros (wheat), re habitat and resemblance of the inflorescence to that of wheat.
Habit, vegetative morphology. Annual; caespitose. Culms 20–40 cm high; herbaceous. Culm nodes glabrous. Culm internodes hollow. Leaves not basally aggregated; auriculate. Sheath margins joined, or free. Leaf blades linear to linear-lanceolate; 1–7 mm wide; flat; without cross venation; persistent; rolled in bud; an unfringed membrane; truncate; 0.4–2 mm long.
Reproductive organization. Plants bisexual, with bisexual spikelets; with hermaphrodite florets.
Inflorescence. Inflorescence a single spike (the spikelets often divergent from the rachis); espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes usually disarticulating; usually either falling entire, or disarticulating at the joints. Spikelets solitary; not secund; alternately distichous; sessile.
Female-fertile spikelets. Spikelets 9–25 mm long; compressed laterally; disarticulating above the glumes; disarticulating between the florets. Rachilla prolonged beyond the uppermost female-fertile floret; the rachilla extension with incomplete florets. Callus blunt.
Glumes two; relatively large; more or less equal; shorter than the adjacent lemmas, or long relative to the adjacent lemmas; joined, or free; lateral to the rachis; pointed; not subulate; shortly awned, or awnless; carinate; similar (becoming very hard at maturity). Lower glume 1–4 nerved. Upper glume 1–4 nerved. Spikelets with incomplete florets. The incomplete florets distal to the female-fertile florets. Spikelets without proximal incomplete florets.
Female-fertile florets 3–6. Lemmas similar in texture to the glumes (leathery); not becoming indurated; awnless, or mucronate, or awned. Awns when present, 1; apical; non-geniculate; entered by several veins. Lemmas hairy, or hairless; carinate; 5–7 nerved; with the nerves confluent towards the tip. Palea present; conspicuous but relatively short; entire to apically notched; awnless, without apical setae, or with apical setae (via prolongation of the keels); thinner than the lemma (membranous); not indurated; 2-nerved; 2-keeled. Lodicules present; 2; free; membranous; ciliate; toothed, or not toothed. Stamens 3. Anthers 0.5–1.3 mm long; not penicillate. Ovary hairy. Styles free to their bases. Stigmas 2; white.
Fruit, embryo and seedling. Fruit somewhat adhering to lemma and/or palea; small to large; longitudinally grooved; slightly compressed dorsiventrally; with hairs confined to a terminal tuft. Hilum long-linear. Embryo small.
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae absent. Mid-intercostal long-cells rectangular and fusiform; having straight or only gently undulating walls (these thin). Microhairs absent. Stomata common; 41.5–56 microns long. Subsidiaries parallel-sided. Guard-cells overlapped by the interstomatals. Intercostal short-cells absent or very rare (excluding macrohair bases). Macrohair bases abundant. Costal short-cells neither distinctly grouped into long rows nor predominantly paired (solitary). Costal silica bodies horizontally-elongated crenate/sinuous, or horizontally-elongated smooth.
Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll with non-radiate chlorenchyma; without adaxial palisade. Leaf blade ‘nodular’ in section; with the ribs more or less constant in size. Midrib not readily distinguishable; with one bundle only. Bulliforms not present in discrete, regular adaxial groups (the epidermis large-celled). All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders absent (strands only). Sclerenchyma all associated with vascular bundles.
Cytology. Chromosome base number, x = 7. 2n = 14 and 28. 2 and 4 ploid. Haplomic genome content F. Haploid nuclear DNA content 5.5 pg (1 species, 2x). Mean diploid 2c DNA value 11 pg (1 species).
Taxonomy. Pooideae; Triticodae; Triticeae.
Distribution, ecology, phytogeography. 5 species; Mediterranean to central Asia. Xerophytic; species of open habitats. Stony slopes, steppe, semi-desert.
Holarctic. Boreal and Tethyan. Euro-Siberian. Mediterranean and Irano-Turanian. European.
Rusts and smuts. Smuts from Tilletiaceae and from Ustilaginaceae. Tilletiaceae — Tilletia. Ustilaginaceae — Ustilago.
Economic importance. Important native pasture species: E. bonaepartis.
References, etc. Morphological/taxonomic: Löve 1984. Leaf anatomical: this project.
Illustrations. • Inflorescence detail. • Inflorescence detail. • Spikelet
Cite this publication as: Watson, L., and Dallwitz, M. J. (1992 onwards). ‘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.’ http://biodiversity.uno.edu/delta/. Version: 18th August 1999. Dallwitz (1980), Dallwitz, Paine and Zurcher (1993 onwards, 1998), and Watson and Dallwitz (1994), and Watson, Dallwitz, and Johnston (1986) should also be cited (see References).
