Paspalum

1. Spikelets < or equal 2 mm long (rarely longer in P. setaceum)…3

1. Spikelets > 2 mm long…2

2. Spikelets long-silky, the silk much exceeding the spikelets…P. urvillei (Spikelets with pilose margins in P. dilitatum also, but this species not known in Palm Beach or Martin counties)

2. Spikelets glabrous or with short pubescence (not with long silky hairs)…5

3. Inflorescence branches forming an even Y (may have an additional branch below that)…P. conjugatum (spikelets usually ca. 1.3 mm long, silky)

3. Inflorescence not forming a Y (or so, but the peduncles at the base of each raceme unequal)…4

4. Spikelets ca. 1.3 mm long…P. blodgettii (spikelets glandular-pubescent)

4. Spikelets 1.4-2 mm long (rarely longer)…P. setaceum (often with axillary inflorescences)

5. Seashore or brackish-shore species (also used for lawn as “Seashore Paspalum”). Spikelets boat-shaped or lanceolate…P. vaginatum (strongly stoloniferous. Leaves with homogeneous adaxial papillae vs. dimorphic in Sporobolus virginicus, ligules with long cilia) (a similar species is P. distichum, but this species is less maritime, and not recorded in our area)

5. Plants not maritime. Spikelets orbicular to broadly elliptic or ovate, the tip rounded or acute…6

6. Leaves terete. Glume with 1 vein…P. monostachyum

6. Leaves flat or involute. Upper (usually only) glume with 3 or more veins…7

7. Spikelets solitary...12

7. Spikelets paired. Inflorescence branches solitary, or racemose…8

8. Upper glume 3-veined. Spikelet nearly orbicular, > 2 mm wide…P. praecox (the veins 3 + 3 vs. 3 + 5 in P. laeve and racemes 4-6 vs. 3-4 in P. laeve, which is not widely reported for our area)

8. Upper glume 5-veined. Spikelet elliptic, usually < 2 mm wide (can go to 3 mm wide in P. floridanum)…9

9. Spikelets mostly 3-4 mm long, 2-3 mm wide…P. floridanum (sheaths and adaxial leaf blades tending to be villous)

9. Spikelets mostly 3 or fewer mm long, narrower than 2 mm…10

10. Spikelets 2-2.2 mm long…P. boscianum (rachis very broad, 2 mm)

10. Spikelets > 2.2 mm long…11

11. Lemma 5-veined. Spikelet 1.4-1.8 mm wide…P. nicorae (rachis < 1 mm wide; spikelets pubescent)

11. Lemma 3-veined. Spikelet 1-1.3 mm wide…P. pleostachyum (inflorescence branches usually > 6; leaf blades marginally serrulate)

12. Upper inflorescence branches often forming a nearly even Y...P. notatum (1-3 branches sometimes present below the terminal pair. Bahia grass - spikelets 2.5-3.5 mm long - a turf species)

12. Upper inflorescence branches usually 3 or 4 and racemose (branching from a central axis)...P. laeve (compare with P. praecox which has paired spikelets, veins 3 + 3 vs. 3 + 5, and racemes 4-6 vs. 3-4)