Paspalum
Plants annual or perennial; cespitose, rhizomatous, or stoloniferous. Culms 3-400 cm, erect, spreading or prostrate, sometimes trailing for 200+ cm. Sheaths open; auricles sometimes present; ligules membranous. Inflorescences terminal, sometimes also axillary, panicles of 1-many spikelike branches, these digitate or racemose on the rachis, spreading to erect, 1 or more branches completely or partially hidden in the sheaths in some species; branch axes flattened, usually narrowly to broadly winged, usually terminating in a spikelet, sometimes extending beyond the distal spikelet but never forming a distinct bristle; disarticulation below the glumes. Spikelets subsessile to shortly pedicellate, planoconvex, rounded to acuminate, dorsally compressed, not subtended by bristles or a ringlike callus, solitary or paired (1 spikelet of the pair reduced in some species), in 2 rows along 1 side of the branches, with 2 florets, first rachilla segment not swollen, upper glumes and upper lemmas adjacent to the branch axes; lower florets sterile; upper florets sessile or stipitate, bisexual, acute or rounded. Lower glumes absent or present only on some spikelets of each branch, without veins or 1-veined, unawned; upper glumes and lower lemmas subequal, membranous, apices rounded, unawned; lower paleas absent or rudimentary; upper lemmas convex, indurate, smooth to slightly rugose, stramineous to dark-brown, margins scarious, involute, clasping the paleas; upper paleas indurate, smooth to slightly rugose, stramineous to dark-brown. Caryopses orbicular to elliptical, planoconvex or flattened, white, yellow, or brown, x = 10, 12.
Distribution
Conn., N.J., N.Y., Wash., Va., Del., D.C, Wis., W.Va., Pacific Islands (Hawaii), Ont., Fla., N.H., Tenn., N.Mex., Tex., La., Ala., Ark., Miss., Okla., Puerto Rico, S.C., Virgin Islands, N.C., Pa., Mass., R.I., Vt., Nev., Colo., Md., Ga., Utah, Calif., Ill., Ind., Iowa, Kans., Ariz., Idaho, Nebr., Oreg., Ohio, Mo., Minn., Mich., Mont., Ky., S.Dak.
Discussion
Paspalum includes 300-400 species, most of which are native to the Western Hemisphere. Forty-three species are found in the Flora region; twenty-four are native. Paspalum scrobiculatum is grown as a grain in India, and several species are grown as forage plants. There are also many weedy species in the genus. Nineteen of the species growing in the Flora region are introduced, and some of them are weedy. Because weeds are under-represented in most herbaria, the distribution maps of such species probably understate their prevalence.
Selected References
Lower Taxa
Key
1 | Spikelets solitary, not associated with a naked pedicel or rudimentary spikelets. | > 2 |
2 | Panicles with 1-70 branches, if more than 1, the branches racemosely arranged. | > 3 |
3 | Branches 7-70, disarticulating at maturity, the axes extending beyond the distal spikelets | Paspalum repens |
3 | Branches 1-6, persistent, terminating in a spikelet. | > 4 |
4 | Upper florets olive to dark brown | Paspalum scrobiculatum |
4 | Upper florets pale to stramineous. | > 5 |
5 | Axes of panicle branches 0.6-1.3 mm wide | Paspalum laeve |
5 | Axes of panicle branches 1.8-3.3 mm wide. | > 6 |
6 | Spikelets 1.7-2.1 mm long; upper lemmas glabrous throughout | Paspalum dissectum |
6 | Spikelets 3.2-4 mm long; upper lemmas with a few short hairs at the apices | Paspalum acuminatum |
2 | Panicles usually composed of a terminal pair of branches, sometimes with 1(-5) additional branches below the terminal pair. | > 3 |
7 | Upper glumes pilose on the margins or shortly pubescent on the back. | > 8 |
8 | Spikelets 1.3-1.9 mm long; upper glumes pilose along the margins | Paspalum conjugatum |
8 | Spikelets 2.4-3.2 mm long; upper glumes sparsely short pubescent on the back | Paspalum distichum |
7 | Upper glumes glabrous. | > 8 |
9 | Spikelets elliptic, their apices acute to acuminate. | > 10 |
10 | Plants rhizomatous, not appearing cespitose; usually in brackish to salt marsh habitats | Paspalum vaginatum |
10 | Plants shortly rhizomatous but appearing cespitose; usually in disturbed inland habitats | Paspalum almum |
9 | Spikelets ovate to broadly elliptic, their apices obtuse to broadly acute. | > 10 |
11 | Spikelets 2.5-4 mm long; leaf blades flat or conduplicate | Paspalum notatum |
11 | Spikelets 1.9-2.3 mm long; leaf blades flat | Paspalum minus |
1 | Spikelets paired, if only 1 spikelet functional, a naked pedicel or rudimentary, non-functional spikelet present. | > 2 |
12 | Spikelets 1-1.3 mm long. | > 13 |
13 | Panicle branches 2-6; spikelets elliptic to elliptic-obovate, appressed to the branch axes | Paspalum blodgettii |
13 | Panicle branches 18-50; spikelets ovate, diverging from the branch axes | Paspalum paniculatum |
12 | Spikelets 1.3-4.1 mm long. | > 13 |
14 | Margins of upper glumes and lower lemmas ciliate-lacerate and winged or pilose. | > 15 |
15 | Upper glumes and lower lemmas ciliate-lacerate, winged | Paspalum fimbriatum |
15 | Upper glumes and lower lemmas pilose. | > 16 |
16 | Panicle branches 2-7; spikelets 2.3-4 mm long | Paspalum dilatatum |
16 | Panicle branches (4)10-30; spikelets 1.8-2.8 mm long | Paspalum urvillei |
14 | Margins of upper glumes and lower lemmas neither ciliate-laceerate nor winged, glabrous or pubescent, if pubescent then the hairs not pilose, often glandular, papillose-based, or wrinkled. | > 15 |
17 | Upper florets olive to dark brown. | > 18 |
18 | Plants aquatic, the culms decumbent, rooting at the nodes; lower glumes often present | Paspalum modestum |
18 | Plants not aquatic or, if aquatic, the culms erect; lower glumes absent. | > 19 |
19 | Panicle branches 10-28 or more. | > 20 |
20 | Plants annual; axes of panicle branches broadly winged, wings about as wide as the central portion | Paspalum boscianum |
20 | Plant perennial; axes of panicle branches narrowly winged, wings narrower than the central portion. | > 21 |
21 | Axes of panicle branches 1-1.7 mm wide; spikelets 1.8-2.4 mm wide | Paspalum virgatum |
21 | Axes of panicle branches 0.5-1.2 mm wide; spikelets 1.1-1.8 mm wide | Paspalum conspersum |
19 | Branches 1-10(28). | > 20 |
22 | Plants annual. | > 23 |
23 | Spikelets 1.3-1.8 mm wide, broadly elliptical to orbicular, glabrous; panicles with 1-10(28) branches, the axes 0.7-2.3 mm wide | Paspalum boscianum |
23 | Spikelets 1.7-2.4 mm wide, broadly obovate, shortly pubescent; panicles with 1-5 branches, the axes 0.8-1.3 mm wide | Paspalum convexum |
22 | Plants perennial. | > 23 |
24 | Plants cespitose, rhizomes sometimes present but not well-developed; culms 100-200 cm tall, stout; panicle branches ascending, divaricate, or reflexed. | > 25 |
25 | Leaf blades 7-18 mm wide | Paspalum conspersum |
25 | Leaf blades 2.5-4 mm wide | Paspalum plicatulum |
24 | Plants not cespitose, rhizomatous; culms 10-150 cm tall, varying in thickness; panicle branches ascending. | > 25 |
26 | Rhizomes short, indistinct | Paspalum plicatulum |
26 | Rhizomes long, evident. | > 27 |
27 | Plants aquatic; upper florets chestnut brown | Paspalum wrightii |
27 | Plants not aquatic; upper florets dark brown | Paspalum nicorae |
17 | Upper florets white, stramineous, or golden brown. | > 18 |
28 | Lower lemmas with well-developed ribs over the veins; upper glumes absent | Paspalum malacophyllum |
28 | Lower lemmas not ribbed over the veins; upper glumes present. | > 29 |
29 | Panicles with 15-100 branches. | > 30 |
30 | Plants annual; upper glumes and lower lemmas rugose | Paspalum racemosum |
30 | Plants perennial; upper glumes and lower lemmas smooth. | > 31 |
31 | Plants rhizomatous, not cespitose; branch axes 0.9-1.2 mm wide; panicle branches often arcuate……………..27. P. intermedium | > 32 |
31 | Plants cespitose, not rhizomatous; branch axes 0.3-0.6 mm wide; panicle branches straight. | > 32 |
32 | Panicle branches spreading to reflexed (rarely ascending); leaf blades 10-23 mm wide; axes of panicle branches 0.3-0.4 mm wide | Paspalum coryphaeum |
32 | Panicle branches erect to ascending; leaf blades 4.9-6.1 mm wide; axes of panicle branches 0.5-0.6 mm wide | Paspalum quadrifarium |
29 | Panicles with 1-15 branches. | > 30 |
33 | Spikelet pairs not imbricate; lower glumes usually present | Paspalum bifidum |
33 | Spikelet pairs imbricate; lower glumes absent or present. | > 34 |
34 | Spikelets 1.3-2.5 mm long. | > 35 |
35 | Upper glumes, usually also the lower lemmas, shortly pubescent. | > 36 |
36 | Lower glumes present | Paspalum langei |
36 | Lower glumes absent. | > 37 |
37 | Panicles both terminal and axillary, the axillary panicles partially or completely enclosed by the subtending leaf sheath | Paspalum setaceum |
37 | Panicles all terminal. | > 38 |
38 | Leaf blades involute; culms 80-110 cm tall | Paspalum laxum |
38 | Leaf blades flat; culms 20-75 cm tall. | > 39 |
39 | Spikelets 1.3-2 mm long, 0.7-1 mm wide, elliptic; upper glumes and lower lemmas 5-veined; culm bases swollen | Paspalum caespitosum |
39 | Spikelets 2-2.5 mm long, 1.4-1.6 mm wide, ovate; upper glumes and lower lemmas 3-veined; culm bases not swollen | Paspalum virletii |
35 | Upper glumes and lower lemmas glabrous. | > 36 |
40 | Panicles both terminal and axillary, the axillary panicles partially or completely enclosed by the subtending leaf sheath | Paspalum setaceum |
40 | Panicles all terminal. | > 41 |
41 | Upper panicle branches erect | Paspalum monostachyum |
41 | Upper panicle branches spreading to ascending. | > 42 |
42 | Leaf blades mostly involute; plants of sandy or rocky areas, usually on the coast | Paspalum pleostachyum |
42 | Leaf blades mostly flat; plants of inland areas or, if coastal, then in marshy areas. | > 43 |
43 | Upper glumes and lower lemmas 3-veined. | > 44 |
44 | Leaf blades usually conduplicate, 2.2-8.3 mm wide | Paspalum praecox |
44 | Leaf blades usually flat, 5-10 mm wide | Paspalum virletii |
43 | Upper glumes and lower lemmas 5-veined. | > 44 |
45 | Axes of panicle branches 0.2-0.5 mm wide; ligules 0.2-0.4 mm long | Paspalum caespitosum |
45 | Axes of panicle branches 1.5-2 mm wide; ligules 2.2-4.7 mm long | Paspalum lividum |
34 | Spikelets 2.5-4.1 mm long. | > 35 |
46 | Upper glumes, and usually lower lemmas, pubescent. | > 47 |
47 | Lower glumes present | Paspalum langei |
47 | Lower glumes absent. | > 48 |
48 | Leaf blades 2-5 mm wide; upper glumes and lower lemmas abundantly pubescent, most hairs longer than 0.1 mm; spikelets elliptic | Paspalum bartwegianum |
48 | Leaf blades 4-18 mm wide; upper glumes and lower lemmas glabrous or sparsely pubescent, the hairs shorter than 0.1 mm; spikelets obovate to elliptic | Paspalum pubiflorum |
46 | Upper glumes, and usually lower lemmas, glabrous. | > 47 |
49 | Upper florets golden brown. | > 50 |
50 | Plants not rhizomatous; culms decumbent and rooting at the lower nodes; spikelets 1.3-1.6 mm wide; lower lemmas 5-7-veined; lower glumes often present | Paspalum modestum |
50 | Plants rhizomatous; culms erect, not rooting at the lower nodes; spikelets 1.9-3.1 mm wide; lower lemmas 3-veined. | > 51 |
51 | Panicle branches 1-6; upper glumes 5-veined; leaf blades 3-18 mm wide | Paspalum floridanum |
51 | Panicle branches 1-3; upper glumes 3-veined; leaf blades 3-4 mm wide | Paspalum unispicatum |
49 | Upper florets stramineous to pale, but not golden brown. | > 50 |
52 | Terminal panicle branches erect. | > 53 |
53 | Blades involute; upper glumes 1-veined | Paspalum monostachyum |
53 | Blades flat; upper glumes 3-veined | Paspalum unispicatum |
52 | Terminal panicle branches spreading to ascending. | > 53 |
54 | Spikelets 2.2-2.6 mm long. | > 55 |
55 | Spikelets 1.2-1.5 mm wide, elliptic to obovate | Paspalum lividum |
55 | Spikelets 2-2.8 mm wide, orbicular to suborbicular | Paspalum praecox |
54 | Spikelets 2.6-4.1 mm long. | > 55 |
56 | Plants decumbent, rooting at the lower nodes, not rhizomatous; spikelets obovate to elliptic | Paspalum pubiflorum |
56 | Plants rhizomatous, neither decumbent nor rooting at the lower nodes; spikelets orbicular to elliptic. | > 57 |
57 | Spikelets 2.1-3.1 mm long, 2-2.8 mm wide, orbicular to suborbicular; upper glumes 3-veined; leaf blades conduplicate | Paspalum praecox |
57 | Spikelets 2.9-4.1 mm long, 1.9-3.1 mm wide, suborbicular to elliptic; upper glumes 5-veined; leaf blades flat | Paspalum floridanum |
"decumbent" is not a number.