Part 7 - UNC Herbarium

POACEAE 842
9 Inflorescence units with (2-) 4-7 (-13) racemes; raceme sheaths (4.1-) 5.3-8.0 (-10-1) mm wide; hairs of
the rachis internode and pedicel yellow-tawny when dry ............................................................A. mohrii
9 Inflorescence units with 2-5 (-7) racemes; raceme sheaths (1.5-) 2.0-4.8 (-6.3) mm wide; hairs of the
rachis internode and pedicel gray to whitish when dry.
10 Postflowering peduncles < 10 mm long.
11 Culm sheaths antrorsely scabrous (often hirsute as well); leaf blades usually > 35 cm long.
12 Ligules (0.6-) 0.8 (-1.3) mm long (usually < 1 mm long), with ciliations 0.2-0.9 mm long;
raceme sheaths (1.5-) 2.0-2.5 (-3.0) mm wide (usually < 2.5 mm wide); keels of first
glume often scabrous below the middle.................................................... A. tenuispatheus
12 Ligules (0.7-) 1.2 (-2.2) mm long (usually > 1 mm long), with ciliations 0.0-0.3 mm long;
raceme sheaths (2.0-) 2.4-3.4 (-4.7) mm wide (usually > 2.5 mm wide); keels of first
glume scabrous only above the middle, smooth below.
13 Inflorescences oblong to obpyramidal; spikelets (3.8-) 4.1-4.4 (-5.0) mm long;
anthers usually not marcescent within spikelet; mature peduncles (4 -) 11-35 (-60)
mm long (usually some of them > 10 mm long)......... A. glomeratus var. glomeratus
13 Inflorescences (linear to) oblong; spikelets (3.4-) 3.6-3.8 (-4.6) mm log; anthers
usually marcescent within spikelets; peduncles (2-) 3-5 (-8) mm long........................
........................................................................................ A. glomeratus var. hirsutior
11 Culm sheaths not scabrous (often hirsute); leaf blades < 35 cm long (except in A. glomeratus
var. pumilus).
14 Leaves glabrous.
15 Ligules (0.8-) 1.1 (-1.5) mm long, with ciliations 0-0.1 mm long; basal leaves often
filiform, < 1.5 mm wide, strongly erect ............................................A. perangustatus
15 Ligules (0.2-) 0.5 (-0.8) mm long, with ciliations 0.2-1.3 mm long; basal leaves
usually > 2 mm wide, soon arching.
16 Culm internodes green (or glaucous just below the node only); raceme sheaths
(2.2-) 2.5-3.8) (-4.5) cm long, (1.7-) 2.4-3.1) (-4.0) mm wide; peduncles (1-) 4-
9 (-30) mm long; racemes 2 (-3) per inflorescence unit.......................................
................................................................................. A. virginicus var. decipiens
16 Culm internodes glaucous; raceme sheaths (2.8-) 3.3-4.7 (-6.7) cm long, (3.0-)
3.2-3.8 (-5.2) mm wide; peduncles (2-) 3-4 (-6) mm long; racemes 2-4 (-7) per
inflorescence unit, at least some inflorescence units (especially at culm and
branch apices) with 3 or more racemes................................................................
.................................................. A. virginicus var. virginicus ['smooth variant']
14 Leaves pubescent, at least on the margin near the collar.
17 Keels of first glume often scabrous below the middle; leaves usually > 44 cm long...
.......................................................................................................... A. tenuispatheus
17 Keels of first glume scabrous only above middle; leaves usually < 31 cm long.
18 Pubescence of young culm sheaths appressed; spikelets usually > 4 mm long;
hairs on rachis internode and sterile pedicel dense, long; callus hairs 1.5-5 mm
long................................................................................................A. longiberbis
18 Pubescence of young culm sheaths spreading; spikelets mostly < 4 mm long;
hairs on rachis internode and sterile pedicel rather sparse and short; callus hairs
1-2.5 mm long.
19 Raceme sheaths (2.2-) 2.5-3.8 (-4.5) cm long, (1.7-) 2.4-3.1 (-4.0) mm
wide; racemes 2 (3) per inflorescence unit; spikelets (3.0-) 3.3-3.6 (-4.0)
mm long........................................................... A. virginicus var. decipiens
19 Raceme sheaths (2.3-) 3.4-5.2 (-6.7) cm long, (2.7-) 3.3-4.0 (-5.5) mm
wide; racemes 2-5 (-7) per inflorescence unit; spikelets (2.9-) 3.7-3.9 (-
4.7) mm long................................................... A. virginicus var. virginicus
10 Postflowering peduncles > 15 mm long.
20 Culm sheaths antrorsely scabrous (often hirsute as well).
21 Ligules (1.0-) 1.2 (-2.0) mm long, with ciliations 0-0.3 mm long; keels of first glume
scabrous only above middle................................................ A. glomeratus var. glomeratus
21 Ligules (0.6-) 0.8 (-1.3) mm long, with ciliations 0.2-0.9 mm long; keels of first glume
often scabrous below middle .................................................................... A. tenuispatheus
20 Culm sheaths not scabrous (often hirsute).
22 Culms < 1.2 m tall; leaf blades < 30 cm long and < 3 mm wide; inflorescence units rarely
> 20/culm.
23 Raceme sheaths (2.2-) 2.5-3.8 (-4.5) cm long; spikelets (3.0-) 3.3-3.6 (-4.0) mm
long; leaf blades (2.5-) 3.6 (-5.5) mm wide ..................... A. virginicus var. decipiens
23 Raceme sheaths (2.6-) 4.1-6.6 (-8.5) cm long; spikelets (3.0-) 3.4-5.1 (-5.5) mm
long; leaf blades (0.8-) 1.8 (-3.0) mm wide.
24 Ligules (0.8-) 1.1 (-1.5) mm long, with ciliations 0-0.1 mm long........................