Pyrrhanthera Zotov
Sometimes referred to Rytidosperma, Danthonia sensu lato
Habit, vegetative morphology. Low, mat-forming perennial; rhizomatous and caespitose. Culms 1–3 cm high; herbaceous. Culm nodes glabrous. Culm internodes solid. Leaves mostly basal; non-auriculate. Leaf blades narrow; setaceous to not setaceous; folded; without cross venation; persistent.
Reproductive organization. Plants bisexual, with bisexual spikelets; with hermaphrodite florets.
Inflorescence. Inflorescence reduced to a single spikelet, or few spikeleted (1–3); a single raceme, or paniculate (much reduced); espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent.
Female-fertile spikelets. Spikelets compressed laterally; disarticulating above the glumes; disarticulating between the florets. Rachilla prolonged beyond the uppermost female-fertile floret; hairy, or hairless. Hairy callus absent. Callus very short.
Glumes present; two; more or less equal; exceeding the spikelets (enclosing it); long relative to the adjacent lemmas; hairless; glabrous; awnless; similar (ovate, leathery). Lower glume 7–9 nerved. Upper glume 7–9 nerved. Spikelets with female-fertile florets only, or with incomplete florets. The incomplete florets distal to the female-fertile florets. The distal incomplete florets merely underdeveloped.
Female-fertile florets 2–3. Lemmas similar in texture to the glumes (leathery); not becoming indurated; incised; minutely 3 lobed (3-toothed); not deeply cleft; mucronate (on the teeth); hairy (minutely pilose). The hairs not in tufts; not in transverse rows. Lemmas non-carinate; 9 nerved. Palea present; 2-nerved. Lodicules present; 2; free; fleshy; ciliate. Stamens 3. Anthers not penicillate. Ovary glabrous. Styles free to their bases. Stigmas 2.
Fruit, embryo and seedling. Fruit small; compressed dorsiventrally. Hilum short. Pericarp thick and hard; free (the fruit a tiny nut). Embryo large; waisted; without an epiblast; with a scutellar tail.
Ovule, embryology. Outer integument covering no more than the chalazal half of the ovule. Inner integument discontinuous distally. Synergids haustorial.
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 present; panicoid-type to chloridoid-type; (45–)51–63(–66) microns long; (22.5–)24–25.5(–26.4) microns wide at the septum. Microhair total length/width at septum 1.8–2.6. Microhair apical cells (13.5–)18–24(–25.5) microns long. Microhair apical cell/total length ratio 0.3–0.45. Stomata common; (39–)40–47(–48) microns long. Subsidiaries dome-shaped, or triangular. Guard-cells overlapped by the interstomatals, or overlapping to flush with the interstomatals. Intercostal short-cells common; in cork/silica-cell pairs; silicified. Costal short-cells conspicuously in long rows, or neither distinctly grouped into long rows nor predominantly paired. Costal silica bodies rounded, crescentic, and ‘panicoid-type’; often cross shaped; not sharp-pointed.
Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll with non-radiate chlorenchyma; without adaxial palisade. Leaf blade adaxially flat. Midrib conspicuous; with one bundle only. Bulliforms not present in discrete, regular adaxial groups (confined to a simple fan over the midrib). Many of the smallest vascular bundles unaccompanied by sclerenchyma. Combined sclerenchyma girders present; forming ‘figures’. Sclerenchyma all associated with vascular bundles.
Taxonomy. Arundinoideae; Danthonieae.
Distribution, ecology, phytogeography. 1 species; New Zealand. Species of open habitats; glycophytic. Upland grassy plains.
Antarctic. New Zealand.
References, etc. Morphological/taxonomic: Zotov 1963. Leaf anatomical: this project.
Illustrations. • Abaxial epidermis of leaf blade. Pyrrhanthera (Rytidosperma) exigua. • 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).
