Grass Genera of the World

L. Watson and M. J. Dallwitz


Calamagrostis Adans.

From the Greek kalamos (a reed) and agrostis (a kind of grass), the type species being a reedy grass.

Including Achaeta Fourn., Amagris Raf., Ancistrochloa Honda, Anisachne Keng, Athernotus Dulac, Chamaecalamus Meyen, Cinnagrostis Griseb., Pteropodium Steud., Sclerodeuxia Pilger

Excluding Aniselytron, Deyeuxia, Dichelachne, Stilpnophleum

Habit, vegetative morphology. Perennial (some species reedlike); rhizomatous, or stoloniferous, or caespitose, or decumbent. Culms 10–200 cm high; herbaceous; unbranched above. Culm nodes glabrous. Culm internodes hollow. Leaves not basally aggregated; non-auriculate. Leaf blades linear; narrow; 1–15 mm wide; setaceous, or not setaceous; flat (usually), or rolled (convolute); without cross venation; persistent; rolled in bud; an unfringed membrane (sometimes erose-ciliate); truncate, or not truncate; 1–12 mm long. Contra-ligule present (a membrane), or absent.

Reproductive organization. Plants bisexual, with bisexual spikelets; with hermaphrodite florets; outbreeding; exposed-cleistogamous, or chasmogamous. Apomictic (pseudogamous or non-pseudogamous), or reproducing sexually.

Inflorescence. Inflorescence paniculate; open (rarely), or contracted; when contracted capitate to spicate, or more or less irregular; espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent. Spikelets not secund; pedicellate.

Female-fertile spikelets. Spikelets 3–7(–8) mm long; compressed laterally; disarticulating above the glumes. Rachilla prolonged beyond the uppermost female-fertile floret, or terminated by a female-fertile floret; hairy; the rachilla extension (when present) naked. Hairy callus present (the hairs surrounding and often as long as or much exceeding the lemma). Callus hairs present, more than 0.5 mm long.

Glumes two; more or less equal; exceeding the spikelets; long relative to the adjacent lemmas (the lemma only about 1/2–2/3 as long); pointed (acute to acuminate); awnless; carinate; similar. Lower glume 1 nerved. Upper glume 1–3 nerved. Spikelets with female-fertile florets only; without proximal incomplete florets.

Female-fertile florets 1. Lemmas less firm than the glumes to similar in texture to the glumes (usually hyaline); not becoming indurated; incised; not deeply cleft (emarginate, bilobed or irregularly denticulate); awned. Awns 1; median; from a sinus, or dorsal; when dorsal, from well down the back; non-geniculate, or geniculate; much shorter than the body of the lemma to about as long as the body of the lemma, or much longer than the body of the lemma; entered by one vein. Lemmas hairless; non-carinate; without a germination flap; 3–5 nerved. Palea present; relatively long; entire, or apically notched (via excurrent veins); awnless, without apical setae; textured like the lemma; not indurated (thin); 2-nerved; 2-keeled, or keel-less. Lodicules present; 2; free; membranous; glabrous; not toothed. Stamens 3. Anthers 1–4 mm long; not penicillate. Ovary glabrous; without a conspicuous apical appendage. Styles free to their bases. Stigmas 2.

Fruit, embryo and seedling. Fruit free from both lemma and palea; small. Hilum long-linear. Embryo small; not waisted. Endosperm liquid in the mature fruit, or hard; with lipid. Embryo with an epiblast; without a scutellar tail; with a negligible mesocotyl internode. Embryonic leaf margins meeting.

Seedling with a long mesocotyl; with a tight coleoptile. First seedling leaf with a well-developed lamina. The lamina narrow; 1 veined, or 3 veined.

Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae absent. Long-cells similar in shape costally and intercostally (the costals narrower); of similar wall thickness costally and intercostally (thin walled). Mid-intercostal long-cells rectangular; having markedly sinuous walls. Microhairs absent. Stomata common. Subsidiaries low dome-shaped, or parallel-sided. Guard-cells overlapped by the interstomatals. Intercostal short-cells common; in cork/silica-cell pairs (sometimes), or not paired (but often paired with a prickle or hook); silicified (rarely), or not silicified (usually). Intercostal silica bodies when present, tall-and-narrow. Costal short-cells neither distinctly grouped into long rows nor predominantly paired. Costal silica bodies horizontally-elongated crenate/sinuous, or ‘panicoid-type’; when ‘panicoid type’, nodular.

Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll with non-radiate chlorenchyma. Leaf blade with distinct, prominent adaxial ribs; with the ribs more or less constant in size. Midrib conspicuous; having a conventional arc of bundles (C. epigejos exhibits a large median with a small lateral on either side). Bulliforms present in discrete, regular adaxial groups (in the furrows); in simple fans. All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present; nowhere forming ‘figures’. Sclerenchyma all associated with vascular bundles.

Culm anatomy. Culm internode bundles in three or more rings.

Phytochemistry. Tissues of the culm bases with little or no starch. Fructosans predominantly long-chain. Leaves without flavonoid sulphates (2 species).

Cytology. Chromosome base number, x = 7. 2n = 28, 42, and 56, or 56–91. 4, 6, and 8 ploid (lowest 2n=28?), or 8–13 ploid. Chromosomes ‘large’.

Taxonomy. Pooideae; Poodae; Aveneae.

Distribution, ecology, phytogeography. About 230 species; temperate. Commonly adventive. Mostly helophytic to mesophytic; shade species to species of open habitats; glycophytic, or halophytic (rarely). Diverse habitats, including coastal sand - see ×Ammocalamagrostis.

Holarctic, Paleotropical, Neotropical, and Cape. Boreal, Tethyan, and Madrean. African and Polynesian. Arctic and Subarctic, Euro-Siberian, Eastern Asian, Atlantic North American, and Rocky Mountains. Mediterranean and Irano-Turanian. Sudano-Angolan and West African Rainforest. Hawaiian. Caribbean, Central Brazilian, Pampas, and Andean. European and Siberian. Canadian-Appalachian, Southern Atlantic North American, and Central Grasslands. Sahelo-Sudanian, Somalo-Ethiopian, and South Tropical African.

Hybrids. Intergeneric hybrids with Agrostis. C. epigejos hybridizes with Ammophila arenariaAmmocalamagrostis P. Fourn.; ×Calamophila O. Schwartz = ×Ammocalamagrostis, ×Calammophila Brand = ×Ammocalamagrostis).

Rusts and smuts. Rusts — Puccinia. Taxonomically wide-ranging species: Puccinia graminis, Puccinia coronata, Puccinia striiformis, Puccinia pygmaea, Puccinia brachypodii, Puccinia poarum, and Puccinia recondita. Smuts from Tilletiaceae and from Ustilaginaceae. Tilletiaceae — Entyloma and Urocystis. Ustilaginaceae — Ustilago.

Economic importance. Important native pasture species: C. canadensis, C. inexpansa, C. rubescens, C. montanensis etc. ×Ammocalamagrostis is a useful sandbinder.

References, etc. Leaf anatomical: Metcalfe 1960; this project.

Illustrations. • General aspect


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).

Index