Cortaderia Stapf
From the Argentine native name cortadera (cutting), alluding to the sharp edged leaf blades.
Including Moorea Lemaire
Excluding cf. Chionochloa
Habit, vegetative morphology. Perennial; caespitose (mostly large, tussocky). Culms 100–400 cm high. Culm nodes glabrous. Culm internodes hollow. Leaves mostly basal; non-auriculate. The sheaths disintegrating or rolling. Leaf blades linear (often harsh, with lacerating margins); broad, or narrow; not pseudopetiolate; without cross venation; disarticulating from the sheaths; once-folded in bud; ligule present; a fringe of hairs. Contra-ligule present, or absent.
Reproductive organization. Plants bisexual, with bisexual spikelets, or dioecious; with hermaphrodite florets, or without hermaphrodite florets. The spikelets all alike in sexuality (i.e., on the same plant); hermaphrodite, or hermaphrodite and female-only, or female-only (mainly gynodioecious). Plants outbreeding and inbreeding. Apomictic (non-pseudogamous), or reproducing sexually.
Inflorescence. Inflorescence paniculate (large and plumose or small); open. Inflorescence with axes ending in spikelets. Inflorescence espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent. Spikelets not secund; pedicellate.
Female-fertile spikelets. Spikelets 10–18 mm long; 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 long; pointed.
Glumes two; more or less equal; shorter than the spikelets to about equalling the spikelets (from 2/3 as long); long relative to the adjacent lemmas; hairless; glabrous; pointed; awnless; carinate; similar (narrow, hyaline). Lower glume 1(–3) nerved. Upper glume 1(–3) nerved. Spikelets with incomplete florets. The incomplete florets distal to the female-fertile florets. The distal incomplete florets merely underdeveloped. Spikelets without proximal incomplete florets.
Female-fertile florets 2–3(–6). Lemmas attenuate; similar in texture to the glumes to decidedly firmer than the glumes (membranous or hyaline); not becoming indurated; entire, or incised; when incised, 2 lobed; deeply cleft, or not deeply cleft; awned, or awnless. Awns when awned, 1, or 3; median, or median and lateral (via the lateral lobes); the median similar in form to the laterals (or somewhat more flattened, when laterals present); from a sinus, or apical; non-geniculate to geniculate; hairless; entered by several veins (3). The lateral awns when present, shorter than the median. Lemmas hairy. The hairs in tufts, or not in tufts; in transverse rows, or not in transverse rows. Lemmas non-carinate; 3 nerved. Palea present (glabrous or hairy); relatively long; entire (truncate); awnless, without apical setae (but hairy); not indurated; 2-nerved; 2-keeled. Palea keels wingless. Lodicules present; 2; free; fleshy; ciliate. Stamens 3, or 0 (in female plants of dioecious species). Anthers not penicillate. Ovary glabrous. Styles free to their bases. Stigmas 2; brown.
Fruit, embryo and seedling. Fruit free from both lemma and palea. Hilum long-linear. Embryo large. Endosperm hard; without lipid; containing compound starch grains. Embryo without an epiblast; with a scutellar tail; with an elongated mesocotyl internode. Embryonic leaf margins meeting.
Ovule, embryology. Outer integument covering no more than the chalazal half of the ovule; more than two cells thick at the micropylar margin. Inner integument discontinuous distally; not thickened around the micropyle. Synergids haustorial (strongly developed); exhibiting large, globular starch grains.
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, or differing markedly in wall thickness costally and intercostally. Mid-intercostal long-cells rectangular; having markedly sinuous walls. Microhairs present, or absent; when present, panicoid-type. Stomata absent or very rare, or common. Subsidiaries dome-shaped, or parallel-sided and dome-shaped (C. bifida exhibiting a few parallels). Guard-cells when present, overlapped by the interstomatals (sic). Intercostal short-cells common; in cork/silica-cell pairs and not paired (solitary); when paired silicified. Intercostal silica bodies tall-and-narrow. Costal short-cells conspicuously in long rows and neither distinctly grouped into long rows nor predominantly paired (varying from vein to vein), or neither distinctly grouped into long rows nor predominantly paired (nearly all solitary in C. bifida, solitary and paired in C. selloana). Costal silica bodies variously horizontally-elongated crenate/sinuous, or tall-and-narrow, or ‘panicoid-type’; when panicoid type, mostly short dumb-bell shaped.
Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll with non-radiate chlorenchyma; without adaxial palisade. Leaf blade with distinct, prominent adaxial ribs to ‘nodular’ in section; with the ribs more or less constant in size (broad, flat-topped). Midrib conspicuous (very much so in C. selloana), or not readily distinguishable (C. archboldii); with one bundle only (C. archboldii), or having a conventional arc of bundles. Bulliforms present in discrete, regular adaxial groups (at the bases of the furrows), or not present in discrete, regular adaxial groups (the groups then irregular or ill defined, of small cells); in simple fans (e.g. C. bifida, or more often the groups ill-defined and of small cells cf. Ammophila -e.g. C. selloana). All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present; forming ‘figures’ (in all the bundles). Sclerenchyma not all bundle-associated. The ‘extra’ sclerenchyma in abaxial groups to in a continuous abaxial layer.
Culm anatomy. Culm internode bundles in three or more rings.
Phytochemistry. Leaves containing flavonoid sulphates (4 species), or without flavonoid sulphates (C. fulvida).
Special diagnostic feature. The median lemma awn not strongly flattened, laterals present or absent.
Cytology. Chromosome base number, x = 9. 2n = 36, 72, 90, and 108. 4, 8, 10, and 12 ploid. Chromosomes ‘small’.
Taxonomy. Arundinoideae; Danthonieae.
Distribution, ecology, phytogeography. 24 species; New Zealand, South America. Commonly adventive. Mesophytic to xerophytic; species of open habitats. Hillsides, in scrub and in weedy places.
Neotropical and Antarctic. Caribbean, Venezuela and Surinam, Pampas, and Andean. New Zealand and Patagonian.
Rusts and smuts. Smuts from Ustilaginaceae. Ustilaginaceae — Ustilago.
Economic importance. Significant weed species: C. selloana, perhaps increasing in significance as such. Cultivated ornamentals, especially C. selloana.
References, etc. Morphological/taxonomic: Zotov 1963. Leaf anatomical: Metcalfe 1960; this project.
Illustrations. • General aspect. • Ligule. Cortaderia selloana. • Pollen antigens. • Pollen antigens. • Pollen antigens: cross-reactions against anti-Lolium serum. • Heat stable pollen antigens (allergens): cross-reactions against anti-Lolium serum. • Pollen antigens: cross-reactions against anti-Cynodon serum. • Pollen antigens: cross-reactions against anti-Zea serum. • Pollen antigens: cross-reactions against anti-Zea serum
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).
