1 | Spike breaking up into units of a spikelet with the rachis segment of the next higher spikelet remaining attached; spike distinctly moniliform |
1' | Spike breaking up into units of a spikelet with its supporting rachis segment remaining attached or whole spike falls as one unit; spike narrowly cylindrical, cylindrical, or narrowly ovoid |
2 | Spike breaking up into units of a spikelet with its supporting rachis segment remaining attached, narrowly cylindrical, but distichous and somewhat dorso-ventrally flattened |
2' | Whole spike falls as one unit, narrowly cylindrical, cylindrical or narrowly ovoid, but not distichous nor flattenend |
3 | Spike narrowly cylindrical, (10-)30-65 times as long as wide |
3' | Spike (sub)cylindrical or narrowly ovoid, widest in the basal part, then narrowing into a more slender, cylindrical upper part, 10-20 times as long as wide |
4 | Spike 1.5-4(-5) cm long; apex of apical glumes with 3 awns |
4' | Spike (3-)5-12(-20) cm long; apex of apical glumes with 1 awn and 1-2 lateral teeth at the base |
5 | Glumes with veins equal in width, more or less parallel, protruding from the surface, equally spaced |
5' | Glumes with veins unequal in width, sunk into the glume surface, unequally spaced |
6 | Spike slender with a regular appearance, caused by the awns of all glumes and lemmas being more or less equally long; both glumes of the lowest fertile spikelet always with 3 awns |
6' | Spike stout with an irregular appearance, caused by wide variation in glume and lemma awn development; glumes of lowest fertile spikelets with 2-3 awns or teeth |
7 | Rudimentary spikelets (2-)3 |
7' | Rudimentary spikelets 1 (rarely 2) |
8 | Spike with 2(-3) spikelets, all fertile; spikelets not constricted above; glume apex with 2-3 awns |
8' | Spike with (2-)3-4 spikelets, the upper one sterile; the lowest spikelets constricted above; glume apex with (2-)4-5 awns |