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1 Plant a perennial, forming dense tussocks, the leaves primarily basal, usually very numerous, mostly > 3 dm long, either 0.5-1.5 mm wide and almost always tightly involute, or 1-3 mm wide and flat or folded; flowering only in the growing season following fire. |
2 Leaves 1-3 mm wide, flat or folded; plants with thick, conspicuous rhizomes; matured basal sheaths shredding into fibrous, threadlike fibers [of wet pinelands of FL] |
2 Leaves 0.5-1.5 mm wide and almost always tightly involute; plants cespitose, only occasionally with rhizomes; basal sheaths not disintegating into fibers; [collectively more widespread in our area, though almost strictly Coastal Plain, from NC south to s. FL, west to s. MS]. |
3 Base of blade and collar (and often the upper sheath) with conspicuous tuft or bearding of woolly to villous pubescence (sometimes deciduous on foliage more than a year old); leaves usually glabrous above the basal 2 cm of the blade; [of s. SC south and west to s. FL and s. MS] |
3 Base of blade, collar, and upper sheath lacking a conspicuous tuft of woolly to villous pubescence; leaves with 2 lines of villous pubescence on either side of the midrib on the lower surface extending nearly or entirely the length of the blade (sometimes deciduous on foliage more than a year old); [of n. SC and NC] |
1 Plant an annual or perennial, forming small tufts (or solitary), the leaves primarily cauline, usually few, mostly < 3 dm long (if as long as 3 dm then > 2 mm wide), flat to slightly folded, but not wiry; flowering not strongly triggered by fire. |
4 First glume 3-7 nerved. |
5 Central awn of the lemma (8-) 12-65 (-70) mm long, the lateral awns as long or nearly so |
5 Central awn of the lemma (9-) 12-25 (-30) mm long, the lateral awns 1-4 mm long (or even lacking) |
4 First glume 1-2-nerved. |
6 Central awns spirally coiled at the base (above the awn column), like a corkscrew, ½ to 3 full turns (when dry). |
7 Lateral awns 5-13 mm long, spreading |
7 Lateral awns 1-4 mm long, erect |
8 First glume 1/2 to 2/3 as long as the second glume; lemma 6-11 mm long, glabrous to scaberulous |
8 First glume as long as or nearly as long as the second glume; lemma 3-8 mm long, sparsely appressed- pubescent |
6 Central awns straight to sickle-shaped or curved ( contorted at the base, but not with multiple twists like a corkscew). |
9 Lateral awns < ½ as long as the central awn (or virtually obsolete). |
10 Inflorescences usually widely paniculate, (5-) 15-25 cm wide; loosely cespitose perennial, unbranched upward (or mostly unbranched). |
11 Lateral awns essentially absent or obsolete; central awns 10-25 mm long, falcate; [FL keys] |
11 Lateral awns 3-10 mm long, ca. ½ as long as the central awns; central awns 20-25 mm long, straight; [throughout FL] |
10 Inflorescences spike-like or only thinly paniculate, 1-6 cm wide; annuals, much branched above the base. |
12 Awns flattened at the base |
12 Awns terete at the base. |
13 Lemmas 8-22 mm long; central awn curved ca. 180 degrees at the base |
13 Lemmas 2.5-10 mm long; central awn curved ca. 90 degrees at the base. |
14 Central awn (8-) 12-27 mm long; lateral awns (1-) 6-18 mm long |
14 Central awn mostly 1-10 (-14) mm long; lateral awns 0-5 (-8) mm long |
9 Lateral awns > ½ as long as the central awn. |
15 Sheaths lanose or floccose (the hairs kinked and intertwined); nodes of the panicle axis with tufts of lanose or floccose hairs |
15 Sheaths glabrous to pilose (the hairs straight and usually appressed, not intertwined); nodes of the panicle axis glabrous or pilose. |
16 Awn column (the connivent awns twisted together) or lemma beak (slender, narrowed, and twisted portion of lemma body below the awns) 7-30 mm long; lemma body (including the beak, if present) separated from the awns (or awn column) by an articulation zone, the awns (or awn column) disarticulating at maturity from the lemma. |
17 Panicle spiciform, broadest near the middle, dense, the spikelets overlapping strongly; awns (10-) 20-30 mm long, borne at the summit of a twisted lemma beak 7-30 mm long; culms simple or with very few branches; plants perennial |
17 Panicle almost corymbiform, broadest above the middle, open, the spikelets overlapping only slightly; awns 30-40 mm long, not including the 8-15 mm long column formed by the twisting together of the 3 awn bases; culms often much-branched; plants annual |
16 Awn column or lemma beak absent or < 7 mm long; lemma body not separated from the awns by an articulation zone. |
18 Main lower branches of the panicle divergent from the culm and with pulvini |
18 Main lower branches of the panicle (or pedicels in racemose species) ascending to appressed and lacking pulvini. |
19 Spikelets borne singly at each node of the main axis, the inflorescence thus a spike or raceme |
19 Spikelets 2 or more per node of the main axis at most nodes (a few nodes may have single spikelets), often with side branches present as well, the inflorescence thus a panicle (less commonly a raceme). |
20 First glume 1/3-¾ the length of the second glume |
20 First glume > ¾ the length of the second glume. |
21 Central awn 15-40 mm long; first glume prominently 2- keeled, (8-) 9-14 mm long when mature |
21 Central awn 8-25 mm long; first glume either 1- keeled and 6-14 mm long, or weakly 2- keeled and 5.5-9 (-10) mm long when mature. |
22 Central awn about 2× as thick as the lateral awns, divergent to reflexed; first glume 1- keeled or weakly 2- keeled; [moist to wet habitats]. |
23 Basal internode of the culm 0.3-0.6 mm wide; most nodes of the inflorescence with 1-2 spikelets; all awns spreading, the central spirally twisted basally and often contorted by as much as 180 degrees (best seen in fresh material); central awn 15-20 mm long, lateral awns 11-16 mm long, the ratio of the lateral:central awn length 0.69-0.80; lemma callus beard 0.6-1.0 mm long |
23 Basal internode of the culm 0.7-1.2 mm wide; most nodes of the inflorescence with 3 or more spikelets; central awn spreading to slightly deflexed, not spirally twisted basally, the lateral awns ascending to erect (best seen in fresh material); central awn 13-22 mm long, lateral awns 8-15 mm long, the ratio of the lateral:central awn length 0.55-0.69; lemma callus beard 0.2-0.6 mm long |
22 Central awn < 1.5× as thick as the lateral awns, erect to divergent; first glume 1- keeled (rarely weakly 2- keeled); [dry habitats]. |
24 Culms mostly > 10 dm tall and 3-6 mm in diameter near the base; awns 8-15 mm long; panicle branches > 4 cm long; callus ca. 1.0 mm long |
24 Culms 5-8 (-10) dm tall and 1-4 mm in diameter near the base; awns 12-25 mm long; panicle branches 1-4 cm long; callus 0.4-0.8 mm long. |
25 First glume 1-4 mm longer than the second glume (rarely about equal to it); awns 15-25 mm long, straight or slightly contorted at the base; leaf blades 1-3 mm wide, usually curling |
25 First glume shorter than or about equal to the second glume; awns 12-18 mm long, spirally contorted at the base; leaf blades about 1 mm wide, usually not curling |