Schizachne Hackel
From the Greek schizein (to split) and achne (chaff),alluding to bifid lemmas.
Habit, vegetative morphology. Perennial; caespitose (with short rhizomes). Culms 30–100 cm high; herbaceous; unbranched above. Culm nodes glabrous. Culm internodes hollow. Leaves not basally aggregated; non-auriculate. Sheath margins joined. Leaf blades linear; narrow; 1–4 mm wide; flat, or rolled (convolute); without cross venation; rolled in bud; ligule present; an unfringed membrane; truncate (at back); 0.5–3 mm long.
Reproductive organization. Plants bisexual, with bisexual spikelets; with hermaphrodite florets.
Inflorescence. Inflorescence few spikeleted; paniculate; open (up to 10 cm). Inflorescence with axes ending in spikelets. Inflorescence espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent. Spikelets secund (in the lax panicle); long pedicellate.
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; hairless (glabrous); the rachilla extension with incomplete florets. Hairy callus present (long-pilose). Callus short; blunt.
Glumes two; very unequal; shorter than the spikelets; shorter than the adjacent lemmas; pointed (acute); awnless; carinate, or non-carinate; similar (membranous, ovate-lanceolate). Lower glume (1–)3 nerved. Upper glume 5 nerved. Spikelets with incomplete florets. The incomplete florets distal to the female-fertile florets. The distal incomplete florets 1–2; merely underdeveloped.
Female-fertile florets 3–7. Lemmas decidedly firmer than the glumes (becoming leathery); not becoming indurated; incised; 2 lobed; not deeply cleft (incised to about 1/4); awned. Awns 1; median; dorsal; from near the top (behind the sinus); hairless; about as long as the body of the lemma to much longer than the body of the lemma; entered by one vein. Lemmas hairless; carinate to non-carinate; without a germination flap; 7–13 nerved. Palea present; relatively long, or conspicuous but relatively short, or very reduced; not indurated (membranous); 2-nerved; 2-keeled. Palea keels hairy (ciiate above). Lodicules present; 2; joined to free; fleshy; glabrous; not or scarcely vascularized. Stamens 3. Anthers 1–2 mm long. Ovary glabrous; without a conspicuous apical appendage. Styles free to their bases. Stigmas 2; white.
Fruit, embryo and seedling. Fruit free from both lemma and palea; small, or medium sized (about 4 mm long). Hilum long-linear. Embryo small. Endosperm hard; without lipid; containing compound starch grains. 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; having markedly sinuous walls. Microhairs absent. Stomata absent or very rare. Intercostal short-cells common; not paired; not silicified. Costal short-cells neither distinctly grouped into long rows nor predominantly paired. Costal silica bodies horizontally-elongated crenate/sinuous (a few), or ‘panicoid-type’; mostly elongated, iregularly nodular; not sharp-pointed.
Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll with non-radiate chlorenchyma. Leaf blade ‘nodular’ in section; with the ribs more or less constant in size. Bulliforms present in discrete, regular adaxial groups; in simple fans. All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present; forming ‘figures’. Sclerenchyma all associated with vascular bundles.
Cytology. Chromosome base number, x = 10. 2n = 20. 2 ploid. Chromosomes ‘small’.
Taxonomy. Pooideae; Poodae; Meliceae.
Distribution, ecology, phytogeography. 1 species; North Eurasia, Japan, North America. Mesophytic; shade species. In woods.
Holarctic. Boreal, Tethyan, and Madrean. Euro-Siberian, Eastern Asian, Atlantic North American, and Rocky Mountains. Mediterranean. European and Siberian. Canadian-Appalachian.
Rusts and smuts. Rusts — Puccinia. Taxonomically wide-ranging species: Puccinia coronata.
References, etc. 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).