Agropyron cristatum
 
Crested Wheatgrass

Upper Glume

Regina
10-June-2023

The following items are taken from keys in Flora of Saskatchewan, Fascicle 4, Grasses of Saskatchewan by Anna L. Leighton and Vernon L. Harms.  Family Poaceae is first divided into tribes, then the tribes are divided into genera, and the genera divided into species.  However, there are a number of tribes that are very difficult to distinguish morphologically.  These are grouped into a large, artificial tribe I call "Multitribe".  Multitribe is then divided into groups, and each group is then divided into genera.  The answers are in the order you would normally work through the keys.

Triticeae: Answers to key questions leading to this tribe. 
Mature inflorescence, if breaking into units, then the units not as below; NOT [Mature inflorescence breaking into spikelet units consisting of a sessile fertile spikelet, a hairy pedicel with or without a sterile spikelet at tip, and a hairy rachis joint, all arising at the same point (a node) in specialized panicle branches called rames]
Spikelets not as below; sterile florets if present, either located distal to the fertile floret(s) on the rachilla or paired and attached at the base of a single fertile floret, not paired with the upper glume as below; lemma and palea variously textured, enclosing the flower or not; disarticulation usually above the glumes; NOT [Spikelets usually dorsally compressed, appearing 1-flowered but containing 1 fertile floret and 1 sterile floret, the latter attached to the base of fertile floret opposite the upper glume, resembling the upper glume, and together with the upper glume enveloping the fertile floret; lower glumes minute (sometimes absent) to 3/4 as long as upper glumes and typically wrapping most of the way around the pedicel at base; fertile floret seed-like with chartaceous-indurate lemma and palea enclosing flower and fruit; disarticulation below the glumes with rare exceptions]
Spikelets 1 to many-flowered, subtended by a pair of glumes (only 1 on lateral spikelets in Lolium); palea margins enclosed or not; plants of dry or wet habitats; NOT [Spikelets 1-flowered, lacking glumes; margins of the palea tightly enclosed by the lemma margins on female or perfect florets; plants of wetlands, often emergent aquatic]
Inflorescence a terminal spike with sessile or subsessile spikelets attached broadside at nodes on opposite sides of the rachis; NOT [Inflorescence not as above; if a terminal spike, then the lateral spikelets attached edgewise to the rachis with inner (upper) glume wanting (as in Lolium)]

Agropyron: Answers to key questions leading to this genus.
Spikelets 1 per node, occasionally 2 at some nodes; NOT  [Spikelets 2 or more per node, occasionally 1 at some nodes]
Spikes usually pectinate with spikelets closely-set, regularly-spaced and parallel like the teeth of a comb; spikelets divergent at angles of 30° to 90° from the rachis at maturity; glume keels prominent to base; NOT [Spikes not pectinate with spikelets not arranged as above; spikelets usually appressed to ascending, sometimes somewhat divergent; glumes usually flat at base, sometimes keeled towards tip]
Spikes 1.3-10 (15) cm long; sheaths of upper leaves not inflated; glumes firm-textured, not inflated at base; plants perennial; NOT [Spikes 1.3-2.4 cm long and almost as wide; sheaths of upper leaves distinctly inflated; glumes indurate, prominently inflated at base; plants annual]