Flora of the Southeastern United States
2022 Edition

Colors

Data mode

Account

Login
Sign up

Key to Paspalum

Click the number at the start of a key lead to highlight both that lead and its corresponding lead. Click again to show only the two highlighted leads. Click a third time to return to the full key with the selected leads still highlighted.

1 Spikelets solitary, not associated with rudimentary spikelets or naked pedicels.
..2 Panicles usually composed of a terminal pair of branches, sometimes with 1 (-5) additional branches below the terminal pair.
....3 Upper glumes pubescent on the back or margins.
......4 Spikelets 1.3-1.9 mm long; upper glumes pilose along the margins
......4 Spikelets 2.4-3.2 mm long; upper glumes sparsely pubescent on the back
....3 Upper glumes glabrous.
........5 Spikelets elliptic, acute or acuminate at the tip
........5 Spikelets ovate to broadly elliptic, obtuse to broadly acute at the tip.
..........6 Spikelets 1.9-2.3 mm long; leaf blades flat
..........6 Spikelets 2.5-4.0 mm long; leaf blades flat or longitudinally folded
..2 Panicles with 1-70 branches, if > 1, the branches arranged racemosely.
............7 Panicle branches 7-70, the axes extending beyond the outermost spikelets; panicle branches disarticulating at maturity
............7 Panicle branches 1-6, terminating in a spikelet; panicle branches persistent.
..............8 Upper florets olive to dark brown
..............8 Upper florets pale to tan.
................9 Axes of panicle branches not broadly winged, 0.6-1.3 mm wide.
..................10 Spikelets orbicular, 2.8-3.2 mm wide
..................10 Spikelets slightly longer than broad, 2.0-2.5 mm wide
................9 Axes of panicle branches broadly winged, 1.8-3.3 mm wide.
....................11 Spikelets 3.2-4.0 mm long; upper lemmas with a few short hairs at their tips
....................11 Spikelets 1.7-2.1 mm long; upper lemmas glabrous
1 Spikelets paired, or at least the second nonfunctional spikelet represented by a naked pedicel.
......................12 Spikelets 1.0-1.3 mm long
......................12 Spikelets 1.3-4.1 mm long
........................13 Margins of upper glumes and lower lemmas pilose.
..........................14 Panicle branches 2-7; spikelets 2.3-4.0 mm long
..........................14 Panicle branches (4-) 10-30; spikelets 1.8-2.8 mm long
........................13 Margins of upper glumes and lower lemmas glabrous or pubescent (if pubescent, the hairs not pilose), but neither ciliate-lacerate, winged, nor pilose.
............................15 Upper florets olive to dark brown.
..............................16 Panicle branches 10-28 (or more).
................................17 Plants annual; axes of panicle branches broadly winged, the wings about as wide as the central portion; [common native]
................................17 Plants perennial; axes of panicle branches narrowly winged, the wings narrower than the central portion; [rare exotics].
..................................18 Axes of panicle branches 0.5-1.2 mm wide; spikelets 1.1-1.8 mm wide
..................................18 Axes of the panicle branches 1.0-1.7 mm wide; spikelets 1.8-2.4 mm wide
..............................16 Panicle branches 1-10 (or to 28 in P. boscianum, keyed under both leads).
....................................19 Plants annual.
......................................20 Spikelets 1.3-1.8 mm wide, broadly elliptic to orbicular, glabrous; panicles with 1-10 (-28) branches, the axes 0.7-2.3 mm wide
......................................20 Spikelets 1.7-2.4 mm wide, broadly obovate, shortly pubescent; panicles with 1-5 branches, the axes 0.8-1.3 mm wide
....................................19 Plants perennial.
........................................21 Plants cespitose, rhizomes poorly developed; culms 10-20 dm tall; panicle branches ascending, divaricate, or reflexed.
..........................................22 Leaves 7-18 mm wide
..........................................22 Leaves 2.5-4 mm wide
........................................21 Plants not cespitose, rhizomatous; culms 1-15 dm tall; panicle branches ascending.
............................................23 Rhizomes long, evident
............................................23 Rhizomes short, indistinct
............................15 Upper florets white, stramineous, or golden brown.
..............................................24 Lower lemmas with well-developed cross-ribs over the veins; upper glumes absent
..............................................24 Lower lemmas not ribbed over the veins; upper glumes present.
................................................25 Panicles with 15-100 branches.
..................................................26 Plants annual; upper glumes and lower lemmas rugose
..................................................26 Plant perennial; upper glumes and lower lemmas smooth.
....................................................27 Plant rhizomatous; panicle branch axes 0.9-1.2 mm wide; panicle branches often arcing
....................................................27 Plant cespitose; panicle branch axes 0.3-0.6 mm wide; panicle branches straight.
......................................................28 Panicle branches spreading to reflexed (rarely ascending); leaf blades 10-23 mm wide; axes of panicle branches 0.3-0.4 mm wide
......................................................28 Panicle branches erect to ascending; leaf blades 4.9-6.1 mm wide; axes of panicle branches 0.5-0.6 mm wide
................................................25 Panicles with 1-15 branches.
........................................................29 Spikelets 1.3-2.5 mm long.
..........................................................30 Upper glumes (and usually also the lower lemmas) shortly pubescent.
............................................................31 Lower glumes present
............................................................31 Lower glumes absent.
..............................................................32 Panicles both terminal and axillary, the axillary panicles partially or completely enclosed by the subtending leaf sheath
..............................................................32 Panicles all terminal
..........................................................30 Upper glumes and lower lemmas glabrous.
................................................................33 Panicles both terminal and axillary, the axillary panicles partially or completely enclosed by the subtending leaf sheath
................................................................33 Panicles all terminal.
..................................................................34 Upper panicle branches erect
..................................................................34 Upper panicle branches spreading to ascending.
....................................................................35 Upper glumes and lower lemmas 5-veined
....................................................................35 Upper glumes and lower lemmas 3-veined.
......................................................................36 Lower sheaths villous or hirsute; spikelets 2.6-3.5 mm long
......................................................................36 Lower sheaths glabrous or sparsely papillose pubescent; spikelets 2.2-2.8 mm long
........................................................29 Spikelets 2.5-4.1 mm long.
........................................................................37 Spikelet pairs barely if at all imbricate; lower glumes usually present
........................................................................37 Spikelet pairs imbricate; lower glumes absent or present.
..........................................................................38 Upper glumes pubescent; lower lemmas usually pubescent.
............................................................................39 Lower glumes present
............................................................................39 Lower glumes absent
..........................................................................38 Upper glumes glabrous; lower lemmas usually glabrous.
..............................................................................40 Upper florets golden brown
..............................................................................40 Upper florets pale to tan.
................................................................................41 Terminal panicle branches erect
................................................................................41 Terminal panicle branches spreading to ascending.
..................................................................................42 Plants decumbent, rooting at the lower nodes; spikelets obovate to elliptic
..................................................................................42 Plants rhizomatous; spikelets orbicular to elliptic.
....................................................................................43 Spikelets 2.9-4.1 mm long; 1.9-3.1 mm wide, suborbicular to elliptic; upper glumes 5-veined; leaf blades flat
....................................................................................43 Spikelets 2.1-3.1 mm long, 2.0-2.8 mm wide, orbicular or nearly so; upper glumes 3-veined; leaf blades laterally folded.
......................................................................................44 Lower sheaths villous or hirsute
......................................................................................44 Lower sheaths glabrous or sparsely papillose pubescent

Key A: Paspalum setaceum complex
(by Richard J. LeBlond)

Click the number at the start of a key lead to highlight both that lead and its corresponding lead. Click again to show only the two highlighted leads. Click a third time to return to the full key with the selected leads still highlighted.

1 Blades glabrous to pubescent or sparsely pilose (the margins often ciliate and/or scabrous).
..2 Blades glabrous, crowded toward the base, often recurved, 3-10 mm wide; rachis of panicle branches 0.2-0.6 mm wide; spikelets 1.4-1.8 mm long, 0.9-1.3 mm wide, glabrous (-few glandular hairs); sterile lemma without a midvein
..2 Blades glabrous, sometimes pubescent or sparsely pilose, more strongly cauline, not recurved (though sometimes spreading), 3-18 mm wide; rachis of panicle branches 0.6-1.2 mm wide; spikelets 1.7-2.6 mm long, 1.2-2.1 mm wide, pubescent to glabrous; sterile lemma with or without a midvein.
....3 Blades conspicuously rigid, 2.5-6 (-8) mm wide; spikelets 2.0-2.6 mm long, 1.5-1.8 mm wide
....3 Blades lax to firm (if firm, then more than 6 mm wide); spikelets 1.7-2.4 mm long, 1.2-2.1 mm wide.
......4 Sterile lemma with a midvein; blades dark green to purple; spikelets elliptic to obovate, 1.7-2.0 mm long, 1.2-1.5 mm wide
......4 Sterile lemma without a midvein; blades yellow-green to dark green; spikelets obovate to suborbicular, 1.7-2.4 mm long, 1.5-2.1 mm wide
1 Blades densely pubescent, hirsute, or long pilose.
........5 Blades crowded toward the base, recurved; spikelets 1.4-1.9 mm long, often purple-spotted
........5 Blades more strongly cauline, not recurved (though sometimes spreading); spikelets 1.4-2.5 mm long, not purple-spotted.
..........6 Plants prostrate to widely spreading; rachis of panicle branches 0.6-1.5 mm wide.
............7 Blades 3-8 mm wide, grayish green, densely pubescent with hairs < 1.5 mm; panicle branches 3-6 cm long, rachis 0.7-1.0 mm wide; spikelets 1.8-2.2 mm long, 1.6-1.8 mm wide, suborbicular to orbicular, pubescent; sterile lemma without a midvein
............7 Blades 2-19 mm wide, yellow-green, pilose with hairs 1.5-4 mm long; panicle branches 2-10 cm long, rachis 0.6-1.5 mm wide; spikelets 1.7-2.1 mm long, 1.2-1.6 mm wide, elliptic to obovate (-suborbicular), glabrous or pubescent; sterile lemma with or without a midvein
..........6 Plants erect to spreading; rachis of panicle branches 0.3-1.0 mm wide.
..............8 Spikelets 1.4-1.9 mm long, 1.1-1.6 mm wide; sterile lemma without a midvein; blades grayish green, 1.5-7 mm wide
..............8 Spikelets 1.7-2.5 mm long, 1.5-2.1 mm wide; sterile lemma with or without a midvein; blades light green or yellow-green to dark green, 2-16 mm wide.
................9 Sterile lemma usually with a midvein; blades 2-10 mm wide, hirsute with hairs to 5.5 mm long, light to dark green; spikelets glabrous to sparsely pubescent
................9 Sterile lemma without a midvein; blades 2-16 mm wide, pubescent with hairs < 1.5 mm long to glabrous, yellow-green to dark green; spikelets pubescent to glabrous