Aegilops L.
Aegilops: name for a grass in Theophrastus. From the Greek aegilos (a herb liked by goats, or a goat), with goatlike (referring to whiskery-awned spikelets) and a grass similar to that liked by goats offered as alternative allusions (see Bor 1968).
Including Aegicon Adans., Aegilemma Löve, Aegilonearum Löve, Aegilopodes Löve, Chennapyrum Löve, Comopyrum Löve, Cylindropyrum (Jaub. & Spach) Löve, Gastropyrum (Jaub. & Spach) Löve, Kiharapyrum Löve, Orrhopygium Löve, Patropyrum Löve, Perlaria Fabric., Sitopsis (Jaub. & Spach) Löve
Excluding Amblyopyrum
Habit, vegetative morphology. Annual; rhizomatous, or caespitose. Culms 1580 cm high; herbaceous. Culm internodes hollow. Leaves not basally aggregated; auriculate, or non-auriculate. Leaf blades linear to linear-lanceolate; 1.510 mm wide; usually flat; without cross venation; an unfringed membrane; truncate; 0.20.8 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 (there often being incomplete spikelets at base and tip of the spike).
Inflorescence. Inflorescence a single spike. Rachides hollowed. Spikelets not all embedded. Inflorescence espatheate; not comprising partial inflorescences and foliar organs. Spikelet-bearing axes with substantial rachides; disarticulating (usually); falling entire (occasionally - e.g. Cylindropyrum), or disarticulating at the joints. Spikelets solitary; not secund; distichous; sessile, or subsessile.
Female-fertile spikelets. Spikelets 512 mm long; not noticeably compressed (usually), or compressed laterally; disarticulating above the glumes, or falling with the glumes, or not disarticulating. Rachilla prolonged beyond the uppermost female-fertile floret; hairy; the rachilla extension with incomplete florets. Hairy callus absent. Callus very short; blunt.
Glumes two; more or less equal; shorter than the adjacent lemmas, or long relative to the adjacent lemmas; lateral to the rachis; without conspicuous tufts or rows of hairs; not pointed (usually with one or more teeth or awns); not subulate; awned (sometimes with more than one awn), or awnless; non-carinate (generally rounded on the back); similar (leathery). Lower glume 713 nerved. Upper glume 713 nerved. Spikelets with incomplete florets. The incomplete florets distal to the female-fertile florets. Spikelets without proximal incomplete florets.
Female-fertile florets 28. Lemmas one to three toothed, or awned; similar in texture to the glumes to decidedly firmer than the glumes; becoming indurated to not becoming indurated; entire, or incised; awnless, or mucronate, or awned. Awns when present, 1, or 3; median, or median and lateral; the median similar in form to the laterals (when laterals present); from a sinus, or apical; non-geniculate; much shorter than the body of the lemma to much longer than the body of the lemma; entered by one vein. The lateral awns when present, shorter than the median, or about equalling the median. Lemmas hairy, or hairless; non-carinate (dorsally rounded); 57 nerved (usually), or 913 nerved (Kiharapyrum); with the nerves non-confluent. Palea present; relatively long; apically notched; not indurated (membranous); 2-nerved; 2-keeled. Lodicules present; 2; free; membranous; ciliate; not toothed. Stamens 3. Anthers 1.54.5 mm long; not penicillate. Ovary hairy. Stigmas 2.
Fruit, embryo and seedling. Fruit adhering to lemma and/or palea, or free from both lemma and palea; medium sized; longitudinally grooved; compressed dorsiventrally; with hairs confined to a terminal tuft. Hilum long-linear. Embryo large to small (to about 1/3 the caryopsis length); not waisted. Endosperm hard; without lipid; containing only simple starch grains.
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae absent. Long-cells similar in shape costally and intercostally (though the costals rather 270,4 smaller); of similar wall thickness costally and intercostally (thick walled). Mid-intercostal long-cells rectangular; having markedly sinuous walls (e.g. A. cylindrica), or having straight or only gently undulating walls. Microhairs absent. Stomata common; 4245 microns long. Subsidiaries parallel-sided. Guard-cells overlapped by the interstomatals. Intercostal short-cells common, or absent or very rare; in cork/silica-cell pairs (in A. cylindrica); silicified (in A. cylindrica). Intercostal silica bodies rounded. Crown cells present (abundant costally, in A. cylindrica). Costal short-cells predominantly paired (e.g. in A. cylindrica), or neither distinctly grouped into long rows nor predominantly paired. Costal silica bodies horizontally-elongated crenate/sinuous, or rounded (exclusively, in A. cylindrica), or tall-and-narrow.
Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll with non-radiate chlorenchyma; without adaxial palisade. Leaf blade with distinct, prominent adaxial ribs, or nodular in section (the adaxial ribs wide and low); 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 (or the groups of fairly uniform cells). All the vascular bundles accompanied by sclerenchyma (except the extreme laterals, in A. cylindrica). Combined sclerenchyma girders present, or absent; nowhere forming figures. Sclerenchyma all associated with vascular bundles.
Culm anatomy. Culm internode bundles in one or two rings.
Cytology. Chromosome base number, x = 7. 2n = 14 and 28, or 42 (rarely). 2, 4, and 6 ploid. Haplomic genome content B, or C, or D, or L, or M, or U, or B and U, or C and D, or C and U, or D and M, or M and U, or D, M, and U. Haploid nuclear DNA content 2.37.5 pg (21 species, mean 5.6). Mean diploid 2c DNA value 11.2 pg (11 species, 7.214.3).
Taxonomy. Pooideae; Triticodae; Triticeae.
Distribution, ecology, phytogeography. 22 species; western Mediterranean to central Asia. Commonly adventive. Xerophytic; species of open habitats.
Holarctic and Paleotropical. Boreal and Tethyan. African. Euro-Siberian. Macaronesian, Mediterranean, and Irano-Turanian. Saharo-Sindian. European.
Hybrids. Intergeneric hybrids with Triticum (×Aegilotriticum Wagner ex Tschermak), Secale (×Aegilosecale Ciferri & Giacom.), Dasypyrum, Elytrigia.
Rusts and smuts. Rusts Puccinia. Taxonomically wide-ranging species: Puccinia graminis, Puccinia striiformis, Puccinia hordei, and Puccinia recondita. Smuts from Tilletiaceae and from Ustilaginaceae. Tilletiaceae Tilletia and Urocystis. Ustilaginaceae Ustilago.
Economic importance. Significant weed species: A. cylindrica, A. geniculata, A. triuncialis. Important native pasture species: several (e.g. A. cylindrica, A. kotschyi, A. triuncialis considered useful).
References, etc. Morphological/taxonomic: Löve 1984. Leaf anatomical: Metcalfe 1960; this project.
Illustrations. Abaxial epidermis of leaf blade
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).