The Grass Genera of the World
The Grass Genera of the World | |
Classical Latin name for rye or spelt.
Habit, vegetative morphology. Annual (rarely perennial); caespitose (or the culms solitary). Culms 20–150 cm high; herbaceous; unbranched above. Culm nodes glabrous. Culm internodes hollow. Leaves not basally aggregated; auriculate. Leaf blades linear; broad, or narrow; 2.5–20 mm wide; flat, or rolled (convolute); without cross venation; persistent; rolled in bud. Ligule an unfringed membrane; truncate.
Reproductive organization. Plants bisexual, with bisexual spikelets; with hermaphrodite florets; outbreeding and inbreeding; exposed-cleistogamous, or chasmogamous.
Inflorescence. Inflorescence a single spike (laterally compressed, distichous). Rachides hollowed. Inflorescence espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes disarticulating, or persistent (in cultivated forms); disarticulating at the joints. Spikelets solitary; not secund; distichous; sessile.
Female-fertile spikelets. Spikelets 10–18 mm long; compressed laterally; falling with the glumes (and the joint), or not disarticulating (in cultivated forms). Rachilla prolonged beyond the uppermost female-fertile floret; hairless. Hairy callus absent. Callus very short.
Glumes two; very unequal to more or less equal; shorter than the adjacent lemmas; free; lateral to the rachis; subulate; acuminate to awned; carinate (sharply keeled to the base); similar (membranous). Lower glume 1 nerved. Upper glume 1 nerved. Spikelets with female-fertile florets only, or with incomplete florets. The incomplete florets distal to the female-fertile florets. The distal incomplete florets 1; merely underdeveloped. Spikelets without proximal incomplete florets.
Female-fertile florets 2–3. Lemmas lanceolate, tapered to the awn; less firm than the glumes to similar in texture to the glumes; entire; pointed; awned. Awns 1; median; apical; non-geniculate; hairless (scabrid); much longer than the body of the lemma; entered by several veins. Lemmas hairless; carinate (the keel with rigid, pectinate cilia); 5 nerved; with the nerves non-confluent. Palea present; relatively long; apically notched; not indurated (hyaline); 2-nerved; 2-keeled. Lodicules present; 2; free; membranous; ciliate. Stamens 3. Anthers 2.3–12 mm long; not penicillate. Ovary hairy. Styles free to their bases. Stigmas 2; white.
Fruit, embryo and seedling. Fruit free from both lemma and palea; medium sized to large; ellipsoid; longitudinally grooved; slightly compressed dorsiventrally to not noticeably compressed; with hairs confined to a terminal tuft. Hilum long-linear. Embryo large to small (to 1/3 the length of the caryopsis). Endosperm hard; without lipid; containing only simple starch grains. Embryo without an epiblast; without a scutellar tail; with a negligible mesocotyl internode. Embryonic leaf margins meeting.
Seedling with a short mesocotyl; with a tight coleoptile. First seedling leaf with a well-developed lamina. The lamina narrow; erect; 9–15 veined (?).
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae absent. Long-cells similar in shape costally and intercostally; of similar wall thickness costally and intercostally. Mid-intercostal long-cells rectangular; having markedly sinuous walls. Microhairs absent. Stomata common; 48–49–51 microns long. Subsidiaries low dome-shaped, or parallel-sided. Guard-cells overlapped by the interstomatals. Intercostal short-cells common; in cork/silica-cell pairs; silicified. Intercostal silica bodies rounded (elliptical), or crescentic. Costal short-cells predominantly paired. Costal silica bodies rounded and crescentic; not sharp-pointed.
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; with the ribs very irregular in sizes. 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; nowhere forming ‘figures’. Sclerenchyma all associated with vascular bundles.
Culm anatomy. Culm internode bundles in one or two rings.
Phytochemistry. Leaves without flavonoid sulphates (1 species).
Cytology. Chromosome base number, x = 7. 2n = 14. 2 ploid. Haplomic genome content R. Chromosomes ‘large’. Haploid nuclear DNA content 7.2–9.5 pg (5 species, mean 8.3). Mean diploid 2c DNA value 16.8 pg (6 species, 14.8–19.0).
Taxonomy. Pooideae; Triticodae; Triticeae.
Distribution, ecology, phytogeography. 5 species; Mediterranean, eastern Europe to central Asia, and South Africa. Commonly adventive. Mesophytic, or xerophytic; species of open habitats. Sandy soils and dry hillsides.
Holarctic. Boreal and Tethyan. Euro-Siberian. Mediterranean and Irano-Turanian. European.
Hybrids. Intergeneric hybrids with Triticum (×Triticosecale Wittmack), Agropyron, Aegilops (×Aegilosecale Ciferri & Giacom.), Hordeum (×Hordale Ciferri & Giacom.), Elytrigia. ×Agrotrisecale Ciferri & Giacom. = Agropyron × Secale × Triticum.
Rusts and smuts. Rusts — Puccinia. Taxonomically wide-ranging species: Puccinia graminis, Puccinia striiformis, Puccinia recondita, ‘Uromyces’ turcomanicum, and ‘Uromyces’ fragilipes. Smuts from Tilletiaceae and from Ustilaginaceae. Tilletiaceae — Tilletia and Urocystis. Ustilaginaceae — Ustilago.
Economic importance. Grain crop species: S. cereale (Rye).
References, etc. Morphological/taxonomic: Löve 1984. Leaf anatomical: Metcalfe 1960; this project.
Miscellaneous. • General aspect. • General aspect. • Rye with Ergot
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: 6th June 2008. http://delta-intkey.com’.
