POACEAE Grasses All old PEI records of Brachyelytrum erectum (Schreb.) P. Beauv. were referred to B. aristosum. The former is a more southern species, in the Maritimes known historically from New Brunswick. Cinna arundinacea L. and Coleataenia longifolia (Torr.) Soreng were reported for PEI are based on MacSwain and Bain (1891), who reported a number of unlikely species. These records are most likely incorrect. Scoggan (1978) reports Eragrostis pectinacea (Michx.) Nees for PEI, who gives an odd range list, saying the species is “known from ON, QU and NS (Pictou, Pictou Co; P.E.I.)”; it seems Scoggan may have listed PEI in error. 1a. All spikelets unisexual; female spikelets borne above male spikelets Zizania palustris L. 1b. Spikelets bisexual or unisexual and with male and female spikelets on separate plants (dioecious) 2a. Spikelets forming a simple spike or spikes, directly sessile or subsessile on main inflorescence axis or at most on secondary branches 3a. Spikelets with a dense basal tuft of silky hairs longer than the glumes, the pedicel glabrous or very short hairy; large (to 2.5 m tall) naturalized exotic plants in anthropogenic settings Miscanthus sacchariflorus (Maxim.) Benth. & Hook. f. ex Franch. 3b. Spikelets not as above; native or introduced species, if introduced then to 1.5 m tall, usually much smaller GROUP A 2b. Spikelets pedicelled and / or on tertiary or further inflorescence branches (check congested inflorescences for reduced panicle branches) 4a. Spikelets with 2 or more florets 5a. Glumes shorter than the lowest lemma; awn of lemma, when present, terminal or lemma with bifid apex GROUP B 5b. Glumes as long as or longer than the lowest lemma, sometimes as long as the entire spikelet; awn, when present, on the back of the lemma GROUP C 4b. Spikelets with a single floret (be careful to note rudimentary florets, plants with which should be keyed above) 6a. Glumes absent; spikelets strongly flattened Leersia oryzoides (L.) Sw. 6b. Glumes present; spikelets not strongly flattened 7a. Spikelets round in cross section or flattened from back to front (dorsiventrally), with a sterile lemma resembling the larger glume present below the fertile lemma (the first glume often resembles a small scale at the base of the spikelet); disarticulation below the membranous glumes GROUP D 7b. Spikelets flattened from side to side (laterally), without a sterile lemma below the fertile lemma; if dorsiventrally flattened, disarticulating above the glumes; if round in cross section, disarticulating below the hardened (indurate) glumes GROUP E GROUP A 1a. Spikes one-sided, with spikelets borne on one side of rachis 2a. Glumes keeled, flattened laterally or not 3a. Glumes equal, about 2-3 mm long, deeply pouch-like and largely covering the floret, the spikelet strongly flattened and about as wide as long; ligule membranous, not ciliate; anthers 0.5-1.0 mm long Beckmannia syzigachne (Steud.) Fernald 3b. Glumes unequal, the longer ones about 3-25 mm long, not pouch-like, the lower glumes shorter than florets; ligules ciliate; anthers 3.0-6.0 mm long Sporobolus (in part) 2b. Glumes rounded on back, not flattened laterally 4a. Lower glume about half the length of the spikelet; upper glume essentially equal in length to sterile lemma; inflorescence branches arranged in a raceme along main axis; ligule absent Echinochloa crus-galli (L.) P. Beauv. 4b. Lower glume minute or rudimentary; upper glume nearly or fully as long as the floret; inflorescence branches from relatively congested origin on main axis; ligule present Digitaria 1b. Spikelets borne on opposite sides of rachis, the spikes not one-sided 5a. Each inflorescence node with 1 spikelet 6a. Spikelets flattened, the narrow edge positioned against the rachis Lolium 6b. Spikelets positioned with broad face against the rachis 7a. Keels of the lemmas centered; perennials Elymus (in part) 7b. Keels of the lemmas off centre, nearer one margin than the other; annuals 8a. Glumes 1-nerved, linear-subulate; lemmas ciliate on keel and margins Secale cereale L. 8b. Glumes 3-nerved, ovate; lemmas not ciliate Triticum aestivum L. 5b. Inflorescences usually with 2 or 3 spikelets per node 9a. Spikelets 3 at each node, each 1-flowered, the lateral ones stalked (except in cultivated barley) and sterile, reduced to awns, the central spikelet sessile and bisexual Hordeum 9b. Spikelets 2 or more at each node, each with 2 or more bisexual florets, all similar and sessile 10a. Lemmas without awns; rhizomes extensively creeping; glumes 2 cm or more, excluding the awns Leymus mollis (Trin.) Pilg. 10b. Lemmas with or without awns, if awnless (or awn as long as a third of the lemma body) then rhizomes absent and glume bodies less than 2 cm long Elymus (in part) GROUP B 1a. Tall reeds to 4 m; panicles large, plumose; rachilla hairs conspicuous, brownish, longer than the lemmas Phragmites 1b. Smaller plants without plumose panicles; rachilla hairs inconspicuous or absent 2a. Spikelets in 1-sided clusters on 2 or 3 naked panicle branches Dactylis glomerata L. 2b. Spikelets not as above 3a. Lemma nerves, callus or base of lemma densely bearded 4a. Lemmas awnless, cobwebby at base, the callus not bearded Poa (in part) 4b. Lemmas awned from apical notch, not cobwebby at base Schizachne purpurascens (Torr.) Swallen 3b. Lemma nerves, callus or base of lemma glabrous, ciliate or minutely pubescent but not densely bearded 5a. Spikelets unisexual; plants dioecious Distichlis spicata (L.) Greene 5b. Spikelets with at least 1 bisexual floret 6a. Lemma tips with 2 teeth and often awned from the notch Bromus 6b. Lemma tips not toothed, the awn, when present, at the tip 7a. Lemmas with 1-3 strong nerves 8a. Ligule membranous, not ciliate; spikelets not strongly flattened Poa (in part) 8b. Ligule ciliate; spikelets strongly flattened Eragrostis minor Host 7b. Lemmas with 5 or more nerves, the ones between the keel and margin often very faint 9a. Lemmas with a prominent midrib Poa (in part) 9b. Lemmas with nerves all about the same 10a. Lateral nerves of lemmas coming together at the apex 11a. Leaves involute, < 3 mm wide Festuca 11b. Leaves flat (margins inrolled when dry), (2.5-) 3.0-8.0 mm wide Lolium 10b. Lateral nerves of lemmas not coming together at the apex 12a. Lemma nerves not prominent or not equally so and not equally spaced; plants mainly halophytic Puccinellia 12b. Lemma nerves raised, equally prominent, +/- equally spaced; plants not halophytic 13a. Lemmas 7-nerved; upper glume 3-nerved; leaf sheaths closed at first, rupturing later; underground rhizomes present Glyceria 13b. Lemmas 5-nerved; upper glume 3-nerved; leaf sheaths open; rhizomes absent, but stems extensively creeping Torreyochloa pallida (Torr.) G.L. Church GROUP C 1a. Spikelets with one bisexual awnless floret with two additional, often dissimilar staminate, sterile, or vestigial lemmas below it 2a. Lower florets staminate, at least as large as bisexual floret, awnless or awned, but evident in the spikelet Anthoxanthum 2b. Lower florets sterile, small and inconspicuous, awnless, only the awnless bisexual floret evident in the spikelet Phalaris 1b. Spikelets usually with 2 or more bisexual florets 3a. Lemmas all awnless; larger glumes +/- broadest above the middle Sphenopholis intermedia (Rydb.) Rydb. 3b. At least some florets with a clear awn (sometimes hidden by glumes); glumes ovate to lanceolate 4a. Larger glumes 6–27 mm long 5a. Lemma with awn arising between terminal teeth Danthonia 5b. Lemma with awn arising dorsally Avena 4b. Larger glumes less than 6 mm long 6a. Basal leaves tufted, involute, mostly setaceous, about 1.5 dm long; panicle branches +/- glabrous; lemma awns geniculate, well exserted Avenella flexuosa (L.) Drejer 6b. Basal leaves flat or tardily involute, 1.5-5.0 mm wide, to 6 dm long; panicle branches +/- scabrous; lemma awns mostly straight, included or only slightly exserted Deschampsia cespitosa (L.) Trin. GROUP D 1a. Spikelets with persistent bristles below, articulated above the bristles, these remaining on inflorescence; ligule a row of hairs Setaria 1b. Spikelets not as above 2a. Second glume or sterile lemma awned or sharp pointed; spikelets often with coarse hairs Echinochloa crus-galli (L.) P. Beauv. 2b. Second glume not as above; spikelets without coarse hairs 3a. Margins of fertile lemma flat, not involute Digitaria 3b. Margins of fertile lemma involute 4a. Terminal panicle 2.5-8 cm long; tufted perennials with clear remnants of old, dead leaves from the previous year present at the base, these sometimes formed into a clear overwintering rosette; flowering spring and fruiting in late spring to early summer Dichanthelium 4b. Terminal panicle 8-40 cm long; anuals, without clear remnants of overwintering basal rosette leaves; flowering and fruiting summer-fall Panicum GROUP E 1a. Inflorescence a dense, symmetrical, cylindric to ovoid, spike-like panicle 2a. Lemma surrounded by a tuft of hairs at the base Ammophila breviligulata Fernald 2b. Lemma not as above 3a. Glumes awned, prominently folded and keeled; lemmas awnless Phleum pratense L. 3b. Glumes not awned 4a. Glumes longer than and enclosing lemma; lemma indurated, appressed-pilose to silky Phalaris 4b. Glumes shorter than or equalling the lemma; lemmas awned on the back below the middle Alopecurus 1b. Inflorescence a branched panicle, either loose and open or contracted, spike-like and lobed or asymmetrical in outline 5a. Lemma conspicuously harder than the glumes in texture 6a. Lemma awned 7a. Leaf blades usually flattened, often glaucous above, becoming slightly involute in drying, more than 4 mm; lemmas 6-9 mm long (excluding awn); glumes distinctly ribbed Oryzopsis asperifolia Michx. 7b. Leaf blades involute, less than 3 mm in diameter; lemma 2-4 mm long (excluding awn); glumes (except midrib) inconspicuously ribbed Piptatheropsis canadensis (Poir.) Romasch., P.M. Peterson & Soreng 6b. Lemma awnless 8a.