Panicum and Steinchisma
1. Spikelets < 1.5 mm longâ€?a href="St_laxa.html">Steinchisma laxa (Panicum laxum)
1. Spikelets > 1.5 mm longâ€?
2. Plants rhizomatous saltwater beach and dune species. Spikelets > 4 mm longâ€?a href="Pa_amarum.html">P. amarum (large grasses with the inflorescences congested. Leaves to 1 cm wide)
2. Plants not beach species (may be rhizomatous). Spikelets usually < 4 mm longâ€?
3. Leaves involute and pseudoterete. Inflorescence axes uprightâ€?a href="Pa_tenerum.html">P. tenerum
3. Leaves flat or at least not pseudoterete; inflorescence axes usually spreading, but sometimes upright...(sometimes P. anceps)â€?
4. Fertile lemma wrinkled (transversely rugose). Inflorescence branches whorled...Urochloa maxima (aka Panicum maximum) (Usually enormous invasive weeds often > 6â€?tall. For additional species with rugose lemmas see Urochloa)
4. Fertile lemmas not transversely rugose. Inflorescence branches whorled or attached singlyâ€?
5. Spikelets distinctly wartyâ€?a href="Pa_verrucosum.html">P. verrucosum (wetland species with open airy inflorescences having the spikelets very widely spaced. Spikelets ca. 2 mm long)
5. Spikelets not wartyâ€?
6. Mature spikelets â€śgapingâ€?(with an open gap at the tip) due to lower palea being indurate (spikelets often gaping also in P. repens, which has a characteristic truncate first glume). When immature, the gaping character may not be apparent, but the upper lemma characteristically papilloseâ€?a href="St_hians.html">Steinchisma hians (leaf blades often ca. 2-3 mm wide, but can be wider)
6. Mature spikelets not gaping, or if gaping, the lower lemma not indurate (except possibly in P. repens)â€?
7. Inflorescence axes upright, the inflorescence more or less cylindric (may be true also of P. anceps but this with a tuft of hairs on the fertile lemma)â€?a href="Pa_hemitomon.html">P. hemitomon
7. Inflorescence axes spreadingâ€?
8 Lower glume 1.8 mm long or longerâ€?a href="Pa_virgatum.html">P. virgatum (inflorescences open and airy, the main branches whorled. Spikelets large 3.5-5 mm)
8. Lower glume < 1.8 mmâ€?
9. Lower glume acute. Fertile lemma with minute tuft of hairs at the apexâ€?0
9. Lower glume truncate or rounded. Fertile lemma with no tuft of hairs apicallyâ€?1
10. Plants with creeping rhizome resembling a â€śchicken foot.â€? Spikelet 2.3-4 mm long. Lower glume 1/3 the spikelet lengthâ€?a href="Pa_anceps.html">P. anceps (incl. P. rhizomatum)
10. Plants not rhizomatous. Spikelet (1.3)1.6-3 mm long. Lower glume half or more the spikelet lengthâ€?a href="Pa_rigidulum.html">P. rigidulum (spikelets often dark-reddish tinged)
11. Nodes swollen. Leaf blades flat, sometimes (not necessarily) with a conspicuous white midvein. Panicle > 5 cm wide. If "rhizomatous," the apparent rhizome merely a prostrate, rooting culm (not scaly). Spikelets green or reddishâ€?a href="Pa_dichotomiflorum.html">P. dichotomiflorum (highly variable in size. Inflorescence branches usually scabrous. Lower glume truncate)
11. Nodes not swollen. Leaf blades folded, the midveins not white. Panicle usually < 5 cm wide. Plants with a scaly rhizome. Spikelets often whiteâ€?a href="Pa_repens.html">P. repens (Plants strongly rhizomatous. Leaves all lying in a single plane and often diverging evenly, like rungs in a ladder. Some stems, with their leaves, having a herringbone pattern. Lower glume truncate.)