Hystrix Moench
From the Greek hustrix (a porcupine), alluding to the inflorescence.
Sometimes referred to Elymus
Habit, vegetative morphology. Perennial; caespitose. Culms 60–200 cm high; herbaceous. Culm nodes hairy (puberulent), or glabrous. Culm internodes hollow. Leaves not basally aggregated; auriculate. Sheath margins joined. Leaf blades linear to linear-lanceolate; broad, or narrow; 3–30 mm wide; flat; without cross venation; an unfringed membrane (tough); truncate; 0.3–1 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 (sometimes with sterile spikelets at the tip of the rachis).
Inflorescence. Inflorescence a single spike, or a false spike, with spikelets on contracted axes. Rachides flattened (continuous). Inflorescence espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent. Spikelets solitary to paired; not secund; distichous (in regular rows).
Female-fertile spikelets. Spikelets 8–18 mm long; adaxial; compressed laterally; disarticulating above the glumes; disarticulating between the florets. Rachilla prolonged beyond the uppermost female-fertile floret; the rachilla extension with incomplete florets. Hairy callus present. Callus blunt.
Glumes present (in the lower spikelets, but often missing from the upper spikelets); two (but small), or one per spikelet (the G1 minute or absent); minute, or relatively large; very unequal; shorter than the spikelets; shorter than the adjacent lemmas; free; displaced (to one side); subulate; awned (the outer one awn-like), or awnless; non-carinate. Lower glume 0–1 nerved. Upper glume 1–2 nerved. Spikelets with incomplete florets. The incomplete florets distal to the female-fertile florets.
Female-fertile florets 2–4. Lemmas convex, tapering into long awns; entire; pointed; awned. Awns 1; median; apical; non-geniculate; much longer than the body of the lemma; entered by several veins. Lemmas hairy, or hairless; non-carinate; without a germination flap; 5–7 nerved; with the nerves confluent towards the tip. Palea present; relatively long; 2-nerved; 2-keeled. Lodicules present; free; membranous; ciliate; not toothed; not or scarcely vascularized. Stamens 3. Anthers 2–7 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 (4–6 mm long); longitudinally grooved; compressed dorsiventrally; with hairs confined to a terminal tuft. Hilum long-linear. Embryo small. 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.
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae absent. Long-cells markedly different in shape costally and intercostally (the costals smaller, more regularly rectangular); of similar wall thickness costally and intercostally (thin walled). Mid-intercostal long-cells rectangular to fusiform; having straight or only gently undulating walls. Microhairs absent. Stomata absent or very rare. Intercostal short-cells absent or very rare. Prickles common. Crown cells absent. Costal short-cells neither distinctly grouped into long rows nor predominantly paired (mostly solitary, or adjoining prickle-bases, but occasionally in short rows). Costal silica bodies horizontally-elongated crenate/sinuous.
Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll without adaxial palisade. Combined sclerenchyma girders present; forming ‘figures’. Sclerenchyma all associated with vascular bundles.
Cytology. Chromosome base number, x = 7. 2n = 28 and 56. 4 and 8 ploid. Haplomic genome content H and S.
Taxonomy. Pooideae; Triticodae; Triticeae.
Distribution, ecology, phytogeography. 9 species; Asia, North America, New Zealand. Mesophytic; shade species and species of open habitats. Woodland and meadows.
Holarctic. Boreal and Tethyan. Atlantic North American and Rocky Mountains. Irano-Turanian. Canadian-Appalachian.
Rusts and smuts. Rusts — Puccinia. Taxonomically wide-ranging species: Puccinia coronata, Puccinia striiformis, Puccinia montanensis, and Puccinia recondita. Smuts from Ustilaginaceae. Ustilaginaceae — Ustilago.
References, etc. Morphological/taxonomic: Löve 1984. Leaf anatomical: this project.
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).