X
Keyed in multiple places:

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.

Click images to enlarge and show more photo credit.

Key to Paspalum

Poaceae

Paspalum

Copy permalink to share

1 Both lower and upper glumes absent, or upper glume present on terminal spikelet only of a panicle branch.
  2 Plants stoloniferous; culms to 40 cm long; blades to 4 mm wide; spikelets 3.8-5.2 mm long, apex acuminate; upper glume sometimes present on terminal spikelet of a panicle branch
  2 Plants cespitose; culms to 200 cm long; blades to 35 mm wide; spikelets 1.8-2 mm long, apex obtuse; both glumes absent from all spikelets
1 At least upper glume present on all spikelets.
    3 Spikelets solitary, not associated with rudimentary spikelets or naked pedicels.
(c) Faccenda, Kevin - CC-BY
      4 Panicles with 1-70 branches; if > 1, the branches arranged racemosely, the 2 uppermost not paired.
(c) Fleming, Gary P.
        5 Panicle branches 7-70, the axes extending beyond the outermost spikelets; panicle branches disarticulating at maturity
(c) Tasney, Greg - CC-BY-SA
        5 Panicle branches 1-6, terminating in a spikelet; panicle branches persistent.
          6 Upper florets pale to tan.
© Scott Ward
             7 Axes of panicle branches not broadly winged, 0.6-1.3 mm wide.
               8 Spikelets slightly longer than broad, 2.0-2.5 mm wide
(c) Johnson, Dan - CC-BY
             7 Axes of panicle branches broadly winged, 1.8-3.3 mm wide.
                 9 Culms to 100 cm long; spikelets 3.2-4 mm long, 1.6-1.7 mm wide; upper lemmas with a few short hairs at their tips; caryopses 2-3 mm long
                 9 Culms to 50 cm long; spikelets 1.7-2.1 mm long 1.1-1.4 mm wide; upper lemmas glabrous; caryopses 1-1.3 mm long
(c) Horn, Jay
      4 Panicles usually composed of a terminal pair of branches, sometimes with 1 (-5) additional branches below the terminal pair.
(c) mark-groeneveld - CC-BY
                   10 Upper glumes pubescent on the back or margins.
                     11 Spikelets 1.3-1.9 mm long; upper glumes pilose along the margins; ligules 0.5-0.8 mm long; panicle branch axis 0.2-0.8 mm wide
                     11 Spikelets 2.4-3.2 mm long; upper glumes sparsely pubescent on the back; ligules 1-2 mm long; panicle branch axis 1.2-2.2 mm wide
(c) Wright, Janet - CC-BY-NC, permission granted to NCBG
                   10 Upper glumes glabrous.
                          13 Plants short-rhizomatous, culms appearing cespitose; blades to 4 mm wide; spikelets 3-3.6 mm long; lower lemmas 5-veined; upper florets stramineous to golden brown; most frequently found along roadsides and in pastures
                          13 Plants rhizomatous, the culms separate; blades to 8 mm wide; spikelets 3-4.5 mm long; lower lemmas 3-veined; upper florets white; most frequently found in brackish and salt marshes
                            14 Culms to 60 cm long; blades flat; panicle branches to 6.4 cm long; spikelets 1.9-2.3 mm long, 1.2-2 mm wide; upper glumes 3-veined
                            14 Culms to 120 cm long; blades flat or longitudinally folded; panicle branches to 15 cm long; spikelets 2.5-4 mm long, 2-2.8 mm wide; upper glumes 5-veined
    3 Spikelets paired, or at least the second nonfunctional spikelet represented by a naked pedicel.
(c) Bradley, Keith
                                       19 Culms to 70 cm long; upper glumes and lower lemmas broadly winged, the wing fimbriate; spikelets 2.4-3 mm wide
                                             22 Plants either not aquatic OR if aquatic then with erect culms; lower glumes absent.
                                                 24 Plants annual; axes of panicle branches broadly winged, the wings about as wide as the central portion; [common native]
                                                 24 Plants perennial; axes of panicle branches narrowly winged, the wings narrower than the central portion; [rare exotics].
Click images to enlarge and show more photo credit.

Key to Poaceae, Key F: grasses of tribe Paniceae (also including grasses keyed as well in Keys B, C, D, and H)

Copy permalink to share | Check for keys that lead to this key

1 Inflorescences spikelike branches, the spikelets partially embedded in the rachises
1 Inflorescences panicles or spikes (if spikes, the spikelets not embedded.
  2 Spikelets (at least the terminal) subtended by 1-many stiff, terete bristles.
    3 Bristles falling with the spikelets at maturity (the disarticulation at the base of the fascicles)
  2 Spikelets not subtended by stiff bristles.
      4 Inflorescences of spikelike branches 1-3.7 cm long, the branch extending 2.5-4 mm beyond the attachment of the distal spikelets
(c) Goldman, Douglas - CC-BY-SA
        5 Upper florets laterally compressed
© Scott Ward
        5 Upper florets dorsally compressed.
          6 Fertile (upper) florets shiny and black to brown-colored when mature; the glumes abruptly apiculate and (internally) oily, the lower glume bases saccate; plants erect, arching, climbing, or decumbent; [s. FL only in our flora area]
          6 Plants not as above (if robust, lacking shiny black florets and not arching or climbing); [collectively widespread, including s. FL].
               8 Leaves > 10× as long as wide; ligules absent or of hairs
               8 Leaves < 8× as long as wide; ligules present, membranous or of hairs.
                 9 Lower glumes unawned or very shortly so; upper glumes ciliate-margined; plants erect or basally decumbent
                 9 Lower glumes awned; upper glumes not ciliate-margined; culms trailing; plants strongly trailing, rooting at the nodes
             7 Lower glumes and lower lemmas unawned.
                   10 Lemma margins flat, hyaline; lower glumes absent or < ¼ the length of the upper glume.
                     11 Subterranean inflorescences absent; aerial inflorescences either with digitate or subdigitate branches and glabrous spikelets, or with elongate rachises and conspicuously pubescent spikelets; spikelets of the aerial inflorescences fertile; spikelets glabrous, ciliate, or pubescent; leaves various (often not as above); [collectively widespread]
                       12 Inflorescence a narrow panicle with the branches strongly ascending to appressed; spikelets ellipsoid to obovoid; [of Coastal Plain pinelands]
                       12 Inflorescence either a panicle with digitate or subdigitate clusters of spikelike branches or a broad panicle with widely divergent branches; [widespread]
                   10 Lemma margins not hyaline, frequently involute; lower glumes various (absent, < ¼ the length, to longer than the upper glume).
                            14 Leaves primarily lacking ligules (at least the upper, and often all, leaves without ligules, if vestigial ligules present, these of hairs)
                              15 Lower (sterile) palea indurate and expanding the spikelet at maturity, as long as the lower (sterile) lemma; lower and upper florets standing apart from one another at maturity; outer surface of the upper (fertile) palea with compound papillae
                              15 Lower (sterile) palea membranous, not expanding the spikelet at maturity, usually shorter than lower (sterile) lemma, or absent; lower and upper florets closely appressed at maturity; outer surface of the upper (fertile) palea lacking compound papillae.
                                  17 Spikelets with lower lemmas (and lower glumes, if present) adjacent to the branch axes.
                                  17 Spikelets with upper lemmas (and upper glumes, if present) adjacent or appressed to the branch axes.
(c) Horn, Jay
                                16 Inflorescence either paniculate with well-developed secondary branchlets or if the primary branches spikelike, then the spikelets not borne in a 1-sided arrangement on the spicate branches.
(c) Sorrie, Bruce A. - CC-BY
                                           21 Inflorescences dense, the spikelets obscuring most of the internal branches
                                             22 First glume shorter, or if this long, then at most 3/4 length of sterile lemma; fertile lemma > ½ the length of the sterile lemma; rachilla not prolonged between the florets.
                                               23 Plant developing a terminal (“spring”) inflorescence usually before mid-summer, followed by lateral (“autumnal”) inflorescences from lower, mid, and/or upper nodes, these often included or hidden among the fascicles of smaller “autumnal” leaves; often developing a rosette of overwintering basal leaves
                                               23 Plant developing a terminal inflorescence usually after mid-summer, the lateral inflorescences, when present, from the upper nodes, usually appearing at the same time as the terminal panicle, and not hidden by dense fascicles of smaller leaves; plants lacking a rosette of overwintering basal leaves.
                                                              30 Lower primary panicle branches in whorls of 4-7 at the nodes, stiffly spreading, naked on the proximal ½, the axils strongly pilose; lower culm internodes appressed papillose-pubescent; first glume acuminate, ½ as long as spikelet; fertile lemma chestnut brown at maturity
Click images to enlarge and show more photo credit.

Key to Poaceae, Key H: finger grasses

Copy permalink to share | Check for keys that lead to this key

1 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; [tribe Paniceae]
  2 Lemma margins hyaline, flat; lower glumes various (absent, < ¼ the length, or longer than the upper glume)
  2 Lemma margins not hyaline, frequently involute; lower glumes absent or < ¼ the length of the upper glume.
    3 Spikelets with lower lemmas (and lower glumes, if present) adjacent to the branch axes.
      4 Lower glumes present on at least most spikelets
    3 Spikelets with upper lemmas (and upper glumes, if present) adjacent or appressed to the branch axes.
        5 Both glumes absent from all or most spikelets
        5 Upper or both glumes present on all spikelets.
          6 Lower glumes usually absent; upper lemmas smooth to slightly rugose
1 Spikelets 1-, 2-, or many-flowered, usually terete or somewhat laterally compressed, either abscising at maturing above the glumes or if 2-flowered then both florets bisexual, or the upper sterile; [tribes Cynodonteae and Zoysieae]
(c) Ward, Scott G
(c) Bradley, Keith
             7 Spikes normally solitary (rarely 2), divergent at the summit of the culm; second glume with a recurved spine arising from the back; fresh plants aromatic with a citrus odor; [tribe Cynodonteae; subtribe “incertae sedis”]
             7 Spikes normally 2 or more, alternate, digitate, subdigitate, or verticillate along the main inflorescence axis; second glume lacking a recurved spine; fresh plants not aromatic with a citrus odor.
               8 Plants stoloniferous, often rather compact and mat-forming, the culms ca. 2-15 cm tall, typically bending and tip-rooting (near the bases of the inflorescences); inflorescences 1.0-2.5 cm long, notably compact and often with abundant leafy bracts
               8 Plants stoloniferous or not (if stoloniferous, then culms not tip-rooting and the inflorescences larger and lacking abundant leafy bracts).
                 9 Spikes arranged along the central inflorescence axis alternately, solitary at each node or inflorescences consisting of a solitary spikelike raceme (Zoysia).
                   10 Spikelets with 1 bisexual floret, sometimes also accompanied by modified male, sterile, or rudimentary florets above the fertile floret.
                     11 Spikelets with modified male, sterile, or rudimentary florets above the fertile floret; [plants of uplands]; [tribe Cynodonteae; subtribe Boutelouinae]
                     11 Spikelets lacking any modified florets; [tribe Zoysieae; subtribes Sporobolinae and Zoysiinae]
                       12 Spikelets with 1 fertile floret accompanied by a sterile, reduced floret; inflorescence of 1-many spike-like panicles (the branches appressed to strongly divergent); [plants of wetlands, primarily saline and coastal]; [tribe Zoysieae; subtribe Sporobolinae]
                       12 Spikelets with 1 solitary fertile floret; inflorescence of solitary spike-like racemes; [waifs or uncommon non-native turf grasses of disturbed areas]; [tribe Zoysieae; subtribe Zoysiinae]
                   10 Spikelets with 2 or more bisexual florets (sometimes also with additional reduced florets); [tribe Cynodonteae; subtribe Eleusininae].
                 9 Spikes arranged along the central inflorescence axis in a digitate, subdigitate, or verticillate manner, all or most nodes with 2 or more spikes; [tribe Cynodonteae].
                              15 Spikelets with 1 fertile floret (there may also be 1 or more sterile florets); [tribe Cynodonteae; subtribe Eleusininae].
                                  17 Lowest lemmas unawned (or with an awn to 1.2 mm long); upper glumes truncate or bilobed, sometimes short-awned from between the lobes
                                    18 Spikes to 7 cm long, terminating in a point (the spikes acuminate); [tribe Cynodonteae; subtribe “incertae sedis”]
                                    18 Spikes to 22 cm long, terminating in a functional or rudimentary spikelet (the spikes acute to obtuse); [tribe Cynodonteae; subtribe Eleusininae].