Poaceae Barnhart
Grass family.
Poaceae, grass family.
Vegetative morphology. Plants herbs; perennial herbs; 0.9–150 cm high (mean 26); caespitose, or not caespitose; without milky juice; not glandular viscid. Taproot absent. Roots white, or yellow. Ground-level or under-ground stems horizontal, or vertical and often branched, or not developed horizontally or vertically; rhizomatous, or stoloniferous; elongate, or compact; 0.3–5 mm wide (mean 1.6). Scales present; smooth, or striate, or grooved; 0.5–40 mm long (mean 16); glabrous, or hairy. Aerial stems erect, or decumbent, or prostrate (rarely); not conspicuously jointed; not filiform; circular or oval in cross-section; without resinous warts, sessile glands or glandular hairs; glabrous, or sparsely hairy, or densely hairy, or scabrous (rarely). Branches not glaucous; epidermis not flaky. Leaves in a basal tuft, or distributed along the stems; alternate; distinctly distichous, or not distinctly distichous; simple; marcescent. Prophylls 0.4–30 mm long (mean 10); with smooth veins, or with scabrous veins, or with hairy veins; with pronounced keels, or lacking pronounced keels. Petioles absent. Sheaths persisting; forming a conspicuous build up at the base of the plant; greyish brown; with the margins fused to the apex, or with the margins fused only in the lower part, or with the margins not fused; glabrous, or with trichomes; pubescent, or hirsute, or scabrous; collars present. Ligules present; 0.1–12 mm long (mean 1.8); membranous, or a fringed membrane; glabrous, or hairy; lanceolate, or ovate-oblong, or transversely oblong; apices acuminate, or acute, or obtuse, or truncate; entire, or erose, or lacerate, or cleft. Leaf blade bases truncate. Blades 5–350 mm long; 0.2–9 mm wide (mean 1.7). Blades appressed to the stem, or spreading, or reflexed; herbaceous; rolled in bud, or folded in bud; linear; with sheath auricles, or with blade auricles, or without auricles; flat, or involute, or folded; veins parallel; midvein conspicuously larger than the lateral veins, or midvein similar in size to other veins in the leaf; bulliform cells in distinct rows on either side of the midvein, or without bulliform cells in a distinct row on either side of the midvein; not septate nodulose. Blades adaxial surface dull; glabrous, or scabrous, or hairy. Blades abaxial surface without sessile glands; glabrous, or scabrous, or hairy. Blade margins not lobed. Blade margins entire; glabrous. Conspicuous hydathodes absent.
Reproductive morphology. Plants bisexual. Flowering stems present. Flowering stems about as high as the leaves, or conspicuously taller than the leaves; glabrous. Flowering culm nodes rooting at the lower nodes, or not rooting at the lower nodes; not exposed, or becoming exposed; number visible 0, or 1, or 2, or 3. Flag leaf sheaths inflated, or not inflated. Leaf or reduced bract closely associated with the base of the inflorescence without calloused tip. Inflorescence spicate, or racemose, or paniculate; dense, or diffuse; linear, or oblong, or lanceolate, or ovate; 0.4–20 cm long (mean 5.4); 2–125 mm wide (mean 22.7); with bulbils, or without bulbils; main axis glabrous, or scabrous, or hairy. Number of inflorescence branches at lowest node 0, or 1, or 2, or 3, or 4, or 5, or 6–7, or 8. Inflorescence primary branches 0.2–105 mm long (mean 17.6); glabrous, or scabrous; with appressed secondary branches, or with spreading secondary branches. Bisexual spike(s) without empty bracts at the base. Spikelets pedicellate, or sessile; disarticulating above the glumes, or disarticulating at the base of the spikelet, or disarticulating at the nodes of the main axis; laterally compressed, or dorsoventrally compressed; oblong, or lanceolate, or ovate, or oblanceolate, or obovate; 1.5–21 mm long (mean 6.3); 0.5–9.2 mm wide (mean 2.5). Florets per spikelet 0–10 (mean 3). Flowers actinomorphic. Floral scales not reflexed; not falling early. First glume 0.02–4.6 × the length of the second glume (mean 0.9); 0.1–1.2 × spikelet length (mean 0.54); 0.05–150 mm long (mean 5); linear, or oblong, or lanceolate, or ovate, or oblanceolate; glabrous, or with trichomes; margins glabrous, or ciliate; veins 0, or 1, or 2, or 3, or 4, or 5; apex caudate, or acuminate, or acute, or obtuse, or truncate. Second glume 0.4 × as long as the spikelet or less, or 0.4–0.9 × as long as the spikelet, or as long, or longer than the spikelet; shorter than the lowest floret, or almost as long as, or longer than, the lowest floret; linear, or oblong, or lanceolate, or ovate, or elliptic, or oblanceolate; 0.3–150 mm long (mean 5.6); glabrous, or with trichomes; veins 0, or 1, or 2, or 3, or 4, or 5, or 6. Rachilla internode 0.083–22 mm long (mean 1.6). Rachilla internode 0.04–0.25 mm wide (mean 0.1). Rachilla internode glabrous, or scabrous, or hairy. Rachilla pronounced between the florets, or not pronounced between the florets; terminating in a well-formed floret, or terminating in a vestigial floret, or extending beyond the uppermost floret. Callus differentiated, or not differentiated; hairs 0–3.5 mm long (mean 0.67); hairs shorter than the floret, or sub-equal to the floret (rarely). Lemma 1.3–4.141–18.5 mm long; oblong, or ovate, or lanceolate, or elliptic, or obovate, or oblanceolate; keeled, or rounded on the back; lemma not strongly incurved, or lemma strongly inrolled; surface shiny, or dull; surface glabrous, or sparsely scabrous, or hairy; surface with trichomes on veins only, or on and between the veins; veins 1, or 2, or 3, or 4, or 5, or 6, or 7. Lemma apex acuminate, or acute, or rounded, or truncate; entire, or erose, or lacerate, or bifid; glabrous, or ciliate; awned, or awnless. Awn arising from the tip, or from below the apex but above the middle, or from the middle or below, or from just above the base; 0–60 mm long (mean 3.8). Palea well developed, or vestigial, or absent; 0.2–14 mm long (mean 3.6); with glabrous veins, or with scabrous veins, or with hairy veins. Perianth reduced to lodicules. Epicalyx absent. Flowers bisexual. Stamens 3; filaments all equal in length; free of the corolla. Anthers yellow; 0.2–7 mm long (mean 1.6). Nectaries absent. Gynoecia superior. Carpels syncarpous; 3. Ovaries glabrous, or hairy. Styles 1, or 2; partially fused; base not enlarged, continuous with the achene. Placentation axile, or basal. Ovules 1. Fruit sessile. Fruit without calyx persisting; dry; a caryopsis; elongate-cylindrical; indehiscent. Fruit 0.9–10 mm long (mean 2.5); glabrous. Legume valves straight. Styles may persist until dehiscence but are not modified. Seeds 1.
Chromosome information. 2n = 14–42–120.
Ecology and habitat. Substrates: acidic, or calcareous, or halophytic, or nitrophilous; rocks, gravel, sand, silt, clay, till, moss; with low organic content, or with high organic content, or peat.
Indigenous knowledge. Aqajait very thin and soft grasses found in rivers or the seas which look like hair (Pleuropogon?) could be used as a bandaid for a cut on the hand (Ootoova et al. 2001). All the grasses ivik in the Cetral Arctic (BUrt 2000).
Cite this publication as: ‘S.G. Aiken, M.J. Dallwitz, L.L. Consaul, C.L. McJannet, L.J. Gillespie, R.L. Boles, G.W. Argus, J.M. Gillett, P.J. Scott, R. Elven, M.C. LeBlanc, A.K. Brysting and H. Solstad. 1999 onwards. Flora of the Canadian Arctic Archipelago: Descriptions, Illustrations, Identification, and Information Retrieval. Version: 29th April 2003. http://www.mun.ca/biology/delta/arcticf/’. Dallwitz (1980) and Dallwitz, Paine and Zurcher (1993, 1995, 2000) should also be cited (see References).