Ammophila Host
From the Greek ammos, sand and philos, loving.
Including Psamma P. Beauv.
Habit, vegetative morphology. Perennial; rhizomatous. Culms 20–130 cm high; herbaceous; unbranched above. Culm nodes glabrous. Culm internodes hollow. Leaves mostly basal; non-auriculate. Leaf blades linear; narrow; 2–5 mm wide (sharp-pointed, blue-green); rolled (convolute); not pseudopetiolate; without cross venation; persistent; rolled in bud; an unfringed membrane; not truncate; 1–30 mm long.
Reproductive organization. Plants bisexual, with bisexual spikelets; with hermaphrodite florets.
Inflorescence. Inflorescence paniculate; contracted; spicate. Primary inflorescence branches inserted all around the main axis. Inflorescence espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent. Spikelets not secund; pedicellate.
Female-fertile spikelets. Spikelets 9–15 mm long; compressed laterally; disarticulating above the glumes. Rachilla prolonged beyond the uppermost female-fertile floret; hairy; the rachilla extension naked. Hairy callus present. Callus short; pointed.
Glumes two; more or less equal; about equalling the spikelets to exceeding the spikelets; long relative to the adjacent lemmas (exceeding them); pointed; 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 similar in texture to the glumes; not becoming indurated; entire, or incised; when incised, 2 lobed; not deeply cleft; minutely awned, or mucronate. Awns 1; median; dorsal; from near the top (subterminal); non-geniculate; much shorter than the body of the lemma; entered by one vein. Lemmas hairless; carinate; without a germination flap; 3 nerved, or 5 nerved; with the nerves non-confluent. Palea present; relatively long; apically notched (minutely); awnless, without apical setae; not indurated (firm); several nerved (often 4-nerved); keel-less. Lodicules present; 2; free; membranous; ciliate, or glabrous; not toothed; not or scarcely vascularized. Stamens 3; with free filaments. Anthers 4–5 mm long; not penicillate. Ovary glabrous. Styles free to their bases. Stigmas 2.
Fruit, embryo and seedling. Fruit medium sized; ellipsoid; longitudinally grooved; compressed dorsiventrally, or not noticeably compressed. Hilum long-linear (two thirds of the fruit length). Embryo small. Endosperm hard; with lipid; containing compound starch grains. Embryo with an epiblast; without a scutellar tail; with a negligible mesocotyl internode. Embryonic leaf margins meeting.
Seedling with a tight coleoptile.
Abaxial leaf blade epidermis. Costal/intercostal zonation lacking. Papillae absent. Long-cells similar in shape costally and intercostally; of similar wall thickness costally and intercostally (walls thick, pitted). Mid-intercostal long-cells rectangular; having markedly sinuous walls, or having straight or only gently undulating walls (different from one specimen to another). 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 (mainly solitary, a few paired). Costal silica bodies absent to poorly developed; in so far as recognisable horizontally-elongated crenate/sinuous (poorly developed, but the silica-cells mainly square, elongated-sinuous or elongated-crenate).
Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll with non-radiate chlorenchyma. Leaf blade with distinct, prominent adaxial ribs; with the ribs very irregular in sizes. Midrib not readily distinguishable; with one bundle only. Bulliforms not present in discrete, regular adaxial groups; in the furrows, in ill defined groups of small, irregularly sized cells. All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present; forming ‘figures’ (each bundle with a large ‘anchor’ - the mesophyll being confined to lateral blocks in the ribs, and immediately beneath the furrows). Sclerenchyma not all bundle-associated (a continuous abaxial layer, linking with the ‘anchors’). The ‘extra’ sclerenchyma in a continuous abaxial layer.
Cytology. Chromosome base number, x = 7. 2n = 14, 28, and 56. 2, 4, and 8 ploid. Chromosomes ‘large’.
Taxonomy. Pooideae; Poodae; Aveneae.
Distribution, ecology, phytogeography. 2 species; North temperate. Commonly adventive. Xerophytic; species of open habitats; halophytic. Sand-binding and dune stabilizing.
Holarctic and Paleotropical. Boreal and Tethyan. African. Euro-Siberian and Atlantic North American. Mediterranean. Saharo-Sindian. European. Canadian-Appalachian.
Hybrids. A. arenaria hybridizes with Calamagrostis epigejos (×Ammocalamagrostis P. Fourn.; ×Calamophila O. Schwartz = ×Ammocalamagrostis, ×Calammophila Brand = ×Ammocalamagrostis).
Rusts and smuts. Rusts — Puccinia. Taxonomically wide-ranging species: Puccinia graminis, Puccinia coronata, and Puccinia pygmaea. Smuts from Ustilaginaceae. Ustilaginaceae — Ustilago.
Economic importance. A. arenaria and ×Ammocalamagrostis widely used as sand stabilizers.
References, etc. Leaf anatomical: Metcalfe 1960; this project.
Illustrations. • General aspect. • General aspect. • Abaxial epidermis of leaf blade. Ammophila arenaria. • Transverse section of leaf blade. Ammophila arenaria. • Transverse section of leaf blade. Ammophila arenaria. • Transverse section of leaf blade. Ammophila arenaria.
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).
