1	"Glume keels winged, ciliate near the base, the glumes glabrous or the veins pubescent"	2
1	"Glume keels without wings, ciliate, the glumes sparsely to densely pubescent elsewhere"	3
2	"Glumes 4.5-7.5 mm long, connate to 1/2 of their length, the apices acute, convergent to parallel; lemma apices acute"	"Alopecurus myosuroides"
2	"Glumes 3-4.5 mm long, connate for more than 1/2 of their length, the apices obtuse, mucronate, divergent; lemma apices truncate"	"Alopecurus creticus"
3	"Plants annual, without rhizomes, not rooting at the lower nodes; blades 1-16 cm long, 0.9-4 mm wide; culms 5-50 cm tall"	4
3	"Plants perennial, often rhizomatous, sometimes rooting at the lower nodes; blades 2-40 cm long, 1-12 mm wide; culms 5-110 cm tall"	6
4	"Glumes 5-6.4 mm long, coriaceous and dilated in the lower 1/2; glume and lemma apices acute to acuminate; anthers about 3 mm long"	"Alopecurus rendlei"
4	"Glumes 2.1-5 mm long, membranous, not dilated below; glume and lemma apices obtuse; anthers 0.4-1 mm long"	5
5	"Upper sheaths conspicuously inflated; glumes 3-5 mm long; lemmas 3-5 mm long, awns exceeding the lemmas by 3-6 mm; panicles 5.5-10 mm wide (excluding the awns)"	"Alopecurus saccatus"
5	"Upper sheaths not inflated; glumes 2.1-3.1 mm long; lemmas 1.9-2.7 mm long, awns exceeding the lemmas by 1.6-4 mm; panicles 3-6 mm wide (excluding the awns)"	"Alopecurus carolinianus"
6	"Glumes 1.8-3.1(3.7) mm long, the apices obtuse; anthers 0.5-2.2 mm long"	7
6	"Glumes 3-6 mm long, the apices acute; anthers 2-4 mm long"	8
7	"Awns geniculate, exceeding the lemmas by 1.2-4 mm; anthers (0.9)1.4-2.2 mm long"	"Alopecurus geniculatus"
7	"Awns straight, not exceeding the lemmas, or exceeding them by less than 2.5 mm; anthers 0.5-1.2 mm long"	"Alopecurus aequalis"
8	"Lemma margins connate only at the base; glumes densely covered with long wooly hairs"	"Alopecurus borealis"
8	"Lemma margins connate for at least 1/3 of their length; glumes with long hairs mainly restricted to the veins"	9
9	"Awns exserted 3-5.5 above the lemma tips; lemma margins straight to slightly convex, forming an acute tip; glume apices parallel or convergent at maturity"	"Alopecurus pratensis"
9	"Awns not exserted beyond the lemma tips or only to 2(3) mm; lemma margins strongly angled tip, forming an obtuse to truncate; glume apices divergent at maturity"	"Alopecurus arundinaceus"