Western Wheatgrass - Elymus smithii
Agropyron smithii, Pascopyrum smithii
MNPS Threat Rank
At initial appearance Elymus triticoides
appears similar to Agropyron smithii
- Elymus smithii
*Glumes: rigid and gradually tapering to a narrow sharp tip, which is often curved; their midribs usually aligned with the lemma's midrib.
*Spikelets mostly singular at mid-spike; occasionally with paired spikelets.Beardless Wildrye
- Elymus triticoides
, native, SOC
*Glumes: Linear to subulate. Tapering from below mid-length into a very narrow pointed tip. Their midribs not aligned with the lemma's midrib; thus, florets are twisted about 90 degrees out of alignment with the glumes, which is a feature that traditionally separates Elymus
*Spikelets always paired at mid-spike; occasionally with 1 or 3 at bottom or top of spike.TAXONOMY
The treatment of perennial grasses that belong to the Triticeae Tribe is contentious among botanists.
In the Manual of Montana Vascular Plants
(Lesica et al. 2012) Lavin's treatment is more traditional, which focuses heavily on morphology:Agropyron
includes native and cultivated grasses that have spikes, usually 1 spikelet per node, several florets per spikelet, and have relatively broader glumes where the mid-ribs of glumes and lemmas align. Elymus
includes native and cultivated grasses that have spikes, having 2 or more spikelets per node where at least 2 spikelets are fertile, and/or having sharp-pointed glumes that do not align with the florets.
In the Flora of North America
(2007) Barkworth's treatment is influenced by various genetic research and the works of Love (1984) and Dewey (1984) and remains partially contentious. Agropyron
are split into 4 genera:Agropyron
is restricted to members with keeled glumes, are called the English Crested Wheatgrasses, and includes only the species Agropyron cristatum
are categorized as alkaline tolerant grasses that are strongly rhizomatous or have short, subulate glumes. Pascopyrum
is categorized as being a North American allooctoploid, which includes only the species Pascopyrum smithii
species are categorized as being obligate outcrossers and have a genome that is either diploid or autotetraploid and also contains the "St" haplome. The only North American species is Pseudoroegneria spicata