Agropyrum

Thickspike wheatgrass Agropyrum dasystachyum, copyright Matt Lavin.

Belongs within: Poaceae.

Agropyron, the crested wheat-grasses, is a genus of perennial grasses native to Eurasia, though widely introduced elsewhere for pasture. Examples include couch grass A. repens which spreads by creeping rhizomes that propagate readily, leading to it becoming regarded as an invasive weed in many regions.

Characters (from Flora of North America Editorial Committee 2007): Plants perennial; densely to loosely caespitose, sometimes rhizomatous. Culms 25-110 cm, geniculate or erect. Sheaths open; auricles usually present; ligules membranous, often erose. Inflorescences spikes, usually pectinate; middle internodes 0.2-3(5.5) mm, basal internodes often somewhat longer. Spikelets solitary, usually more than three times as long as the internodes, usually divergent or spreading from the rachis, with 3-16 florets; disarticulation above the glumes and below the florets. Glumes shorter than the adjacent lemmas, lance-ovate to lanceolate, 1-5-veined, asymmetrically keeled, secondary keel sometimes present on wider side, keels glabrous or with hairs, hairs not tufted, apices acute and entire, sometimes awned, awns to 6 mm; lemmas 5-7-veined, asymmetrically keeled, acute to awned, awns to 4.5 mm; paleas from slightly shorter than to exceeding the lemmas, bifid; anthers 3, 3-5 mm, yellow. Caryopses usually falling with lemmas and paleas attached. x = 7. Haplome P.

Agropyrum
    |--A. dasystachyum CL86
    |--A. enysii W27
    |--A. glaucum D37
    |--A. intermedium H91
    |--A. junceum C74
    |    |--A. j. ssp. junceum C74
    |    `--A. j. ssp. littoreum C74
    |--A. multiflorum A27
    |--A. repens TG88
    |--A. scabrum W27 [incl. A. squarrosum A27]
    |--A. smithii CL86
    |--A. spicatum CL86
    |--A. trachycaulum CL86
    `--A. youngii A27

*Type species of generic name indicated

REFERENCES

[A27] Andersen, J. C. 1927. Popular names of New Zealand plants. Transactions and Proceedings of the New Zealand Institute 57: 905–977.

[C74] Coineau, Y. 1974. Éléments pour une monographie morphologique, écologique et biologique des Caeculidae (Acariens). Mémoires du Muséum National d'Histoire Naturelle, nouvelle série, Série A, Zoologie 81: 1–299, 24 pls.

[CL86] Collins, E. I., & R. W. Lichvar. 1986. Vegetation inventory of current and historic black-footed ferret habitat in Wyoming. Great Basin Naturalist Memoirs 8: 85–93.

[D37] Dobzhansky, T. 1937. Genetics and the Origin of Species. Columbia University Press: New York.

Flora of North America Editorial Committee. 2007. Flora of North America North of Mexico vol. 24. Magnoliophyta: Commelinidae (in part): Poaceae, part 1. Oxford University Press.

[H91] Hubálek, Z. 1991. Biogeographic indication of natural foci of tick-borne infections. In: Dusbábek, F., & V. Bukva (eds) Modern Acarology: Proceedings of the VIII International Congress of Acarology, held in České Budĕjovice, Czechoslovakia, 6–11 August 1990 vol. 1 pp. 255–260. SPB Academic Publishing: The Hague.

[TG88] Tepfer, D., A. Goldmann, N. Pamboukdjian, M. Maille, A. Lepingle, D. Chevalier, J. Dénarié & C. Rosenberg. 1988. A plasmid of Rhizobium meliloti 41 encodes catabolism of two compounds from root exudate of Calystegium sepium. Journal of Bacteriology 170 (3): 1153–1161.

[W27] Wall, A. 1927. Some problems of distribution of indigenuous plants in New Zealand. Transactions and Proceedings of the New Zealand Institute 57: 94–105.