Sclerochloa P. Beauv.
From the Greek skleros ??? (hard) and chloë (grass), alluding to leathery glumes and lemmas.
Including Amblychloa Link, Crassipes Swallen
Habit, vegetative morphology. Annual; caespitose. Culms 4–30 cm high; herbaceous. Culm nodes glabrous. Culm internodes solid. Leaves non-auriculate. Sheath margins joined to free. Leaf blades linear; narrow; flat, or rolled; without cross venation; persistent; once-folded in bud; an unfringed membrane; not truncate; 0.5–1.5 mm long.
Reproductive organization. Plants bisexual, with bisexual spikelets; with hermaphrodite florets.
Inflorescence. Inflorescence one-sided, a single raceme, or paniculate (with short, stout branches); contracted (narrow, rigid). Primary inflorescence branches borne biseriately on one side of the main axis. Inflorescence espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent. Spikelets secund; pedicellate (the pedicels stout, to 1 mm long).
Female-fertile spikelets. Spikelets 6–15 mm long; compressed laterally; falling with the glumes (and with the pedicel); tardily disarticulating between the florets, or not disarticulating between the florets. Rachilla prolonged beyond the uppermost female-fertile floret; hairless; the rachilla extension with incomplete florets. Hairy callus absent.
Glumes two; very unequal; shorter than the spikelets; shorter than the adjacent lemmas; dorsiventral to the rachis; hairless; glabrous; not pointed (obtuse to emarginate); awnless; non-carinate; similar (herbaceous with membranous margins, oblong-ovate, somewhat asymmetric). Lower glume (1–)3–5 nerved. Upper glume 5–9 nerved. Spikelets with incomplete florets. The incomplete florets distal to the female-fertile florets. Spikelets without proximal incomplete florets.
Female-fertile florets 3–8. Lemmas decidedly firmer than the glumes (leathery, the margins membranous); not becoming indurated; entire, or incised; blunt; not deeply cleft (rounded to emarginate); awnless; hairless; glabrous; non-carinate; 5–7 nerved. Palea present; relatively long; not indurated (hyaline); 2-nerved; 2-keeled. Lodicules present; 2; free; membranous; glabrous; toothed. Anthers 0.6–1.5 mm long; not penicillate. Ovary glabrous. Styles free to their bases. Stigmas 2.
Fruit, embryo and seedling. Fruit free from both lemma and palea; small (2.5–3.5 mm long); trigonous. Hilum short (round). Embryo small; not waisted. Endosperm hard; with lipid, or without lipid. Embryo with 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 similar in shape costally and intercostally; of similar wall thickness costally and intercostally. Mid-intercostal long-cells rectangular to fusiform; having straight or only gently undulating walls. Microhairs absent. Stomata common; 21–27 microns long (S. dura), or 33–39 microns long (S. rigida). Subsidiaries parallel-sided. Guard-cells overlapped by the interstomatals. Intercostal short-cells common; not paired (solitary); not silicified. Costal short-cells neither distinctly grouped into long rows nor predominantly paired. Costal silica bodies horizontally-elongated crenate/sinuous, or horizontally-elongated smooth (predomonating), or rounded (some, oval); not sharp-pointed.
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 conspicuous; with one bundle only. Bulliforms not present in discrete, regular adaxial groups (apart from the ‘midrib hinges’). All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present; forming ‘figures’. Sclerenchyma all associated with vascular bundles.
Cytology. Chromosome base number, x = 7. 2n = 14. 2 ploid. Chromosomes ‘large’.
Taxonomy. Pooideae; Poodae; Poeae.
Distribution, ecology, phytogeography. 2 species; southern Europe to western Asia. Commonly adventive. Mesophytic to xerophytic; species of open habitats; halophytic to glycophytic (in dry weedy places and saline soils).
Holarctic. Boreal and Tethyan. Euro-Siberian and Atlantic North American. Mediterranean and Irano-Turanian. European. Central Grasslands.
Rusts and smuts. Rusts — Puccinia. Taxonomically wide-ranging species: ‘Uromyces’ dactylidis.
References, etc. Leaf anatomical: this project.
Illustrations. • 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).
