Sporobolus

1. Spikelets > 4 mm long…  (S. curtisii likewise with long spikelet but leaf blades 2 mm wide vs. wider)

1. Spikelets < 3.9 mm long…2

2. Beach species strictly.  Leaves strongly distichous in a herringbone pattern.  Racemes 1 cm wide, white… (Adaxial surface of leaf blades with dimorphic papillae)

2. Inland species or occasionally maritime; leaves not in a herringbone pattern.  Racemes usually broader than 1 cm, usually not tightly congested…3

3. Spikelets usually < 1 mm long…

3. Spikelets usually > 1 mm long…4

4. Leaf blades 0.8-1(2) mm wide.  Spikelets 2.6-3.8 mm long… (spikelets often  purplish red.  Upper glume equal to the floret.  S. curtisii, probably not in area has even larger spikelets)

4. Leaf blades usually > 2 mm wide (S. indicus may be as narrow as 1 mm).  Spikelets < 2.5 mm long…5

5. Upper glume 0.4-0.7 mm long, less than half the length of the spikelet… (leaf blades < 3 mm wide) (Baaijens & Veldkamp 1991 place this in synonymy under S. indicus)

5. Upper glume > 0.8 mm…6

6. Both glumes much shorter than spikelet.  Upper glume ½-2/3 the spikelet length.  Spikelet 2-2.5 mm long…

6. Upper glume 2/3-almost as long as spikelet.  Spikelet 1.6-2 mm long… (panicles thick and full, very dense; leaf blades to 8 mm wide)