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1 Plant a shrub or tree (the culms perennial, woody, to 25 m tall), with complex branching systems from the upper nodes; leaves strongly dimorphic, those of the main culm sheathing, those of the branches or culm tips pseudopetiolate |
1 Plant an herb (the culms annual, not truly woody, to 5 m tall), lacking complex branching systems from the upper nodes; leaves not dimorphic, none of them pseudopetiolate. |
..2 Plant a robust grass, culms usually > 2 m tall and usually > 5 mm in diameter at the base |
..2 Plant a small to medium grass, culms < 2 m tall and usually also < 5 mm in diameter at the base. |
....3 Spikelets either modified into asexual, purplish bulblets, or partially or wholly concealed either by spines, hooks, and/or involucres, or partially or wholly concealed by being imbedded in a fleshy rachis or cob. |
......4 Fertile spikelets either absent (spikelets modified into asexual, purplish bulblets) or variously spiny or bead like |
......4 Fertile spikelets embedded in a fleshy rachis (resembling a rattail) or a cob |
....3 Spikelets apparent, not covered, concealed, embedded, or modified by spines, hooks, or involucres. |
........5 Spikelets 2-flowered, often dorsally compressed, falling entire at maturity (the abscission below the glumes), the upper floret usually bisexual, the lower one male or sterile. |
..........6 Glumes often as long as or longer than the lemmas and concealing the florets; spikelets usually arranged in obvious pairs or triplets, with 1 spikelet sessile or shortly pedicellate and the other 1 (or 2) spikelets pedicellate (the pedicellate sometimes vestigial or absent) |
..........6 Glumes (the lower or both) shorter than the lemmas (or the glumes absent); spikelets not organized in pairs or triplets |
........5 Spikelets 1-, 2-, or many-flowered, usually terete or somewhat laterally compressed, either abscising at maturity above the glumes or if 2-flowered then both florets bisexual, or the upper sterile. |
............ 7 Inflorescence of one or more spikes, the spikelets sessile (or very short-pedicelled) on the spike axis, 1-more per node, characteristically in 2-more ranks (these either on opposite sides of the axis or crowded on one side), the individual spikelets borne more-or-less touching one another. |
............ ..8 Spikelets borne in a single terminal spike or raceme (an extension of the culm), usually 2-ranked on opposite sides of the axis |
............ ..8 Spikelets borne on 1-many spikes (the spikes themselves arranged digitately, subdigitately, or racemosely on the culm) in 2 (or more) rows; spikelets often on one side of the spike axis |
............ 7 Inflorescence paniculate, sometimes somewhat to very congested, but then not as above. |
............ ....9 Spikelets with a single bisexual floret, and no staminate, sterile, or reduced florets present (occasional spikelets of Muhlenbergia can have 2-3 florets). |
............ ......10 Glumes absent or reduced to tiny rudiments; palea 1-keeled; [of wetlands] |
............ ......10 Glumes present; palea various; [habitats various]. |
............ ........11 Inflorescences dense and spikelike, symmetrical, cylindrical or ovoid, unbranched |
............ ........11 Inflorescences loose and open, or if relatively dense, then with discernible branches, and thus lobed or asymmetrical. |
............ ..........12 Lemmas awnless |
............ ..........12 Lemmas awned |
............ ....9 Spikelets with 2-many florets, including bisexual, staminate, reduced, or sterile flowers. |
............ ............ 13 Glumes (one or both) nearly equaling or surpassing the most apical lemma of the spikelet, therefore partially or completely concealing the florets |
............ ............ 13 Glumes (both) shorter than the most apical lemma of the spikelet, therefore the florets largely visible |
1 Leaves palmately or pinnately lobed. |
..2 Leaves pinnately lobed (the midvein dominant, with 2, 4, or more lateral veins diverging into the lobes from the midvein above the base of the leaf blade) |
..2 Leaves palmately lobed or bilobed (3, 5, or more veins diverging from the base of the leaf blade into the lobes) |
1 Leaves not lobed (entire or serrate, sometimes coarsely so), or only with 2 small auriculate lobes at the base of an otherwise unlobed leaf blade (such as various Magnolia species). |
....3 Woody grasses (bamboos), infrequently flowering, with hollow stems |
....3 Lianas, shrubs, or trees, not grasses, generally with solid stems. |
......4 Lianas (plant generally with obvious adaptations for climbing, such as adventitious roots, twining stems, or tendrils) |
......4 Shrubs, subshrubs, or trees (sometimes scrambling or occasionally high-climbing with the support of other vegetation, but lacking the specialized climbing structures listed above). |
........5 Shrubs or subshrubs. |
..........6 Leaves entire (sometimes ciliate or scabrous on the margin) |
..........6 Leaves serrate, crenate, serrulate, crenulate, or doubly serrate |
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............ 7 Leaves entire (sometimes ciliate or scabrous on the margin) |
............ 7 Leaves serrate, crenate, serrulate, crenulate, or doubly serrate |