Montana Field Guide

PLANTS: A cool season perennial grass. Plants are rhizomatous, not cespitose (densely tufted). Culms are mostly hairless, typically glaucous, andgrow 35-80 cm tall. Sources: Barkworth in Flora of North America [FNA] 2007; Lesica et al. 2012

LEAVES: Often basally concentrated. Blades are usually stiff, often inrolled, and 2-5 mm wide. Sheaths and collars are usually hairless. Lowest internodes are 2 times as long as the middle internodes. Auricles to 1 mm tall, Ligules about 0.1 mm tall. Top of leaf usually has prominently veins. Sources: Barkworth in FNA 2007; Lesica et al. 2012.

INFLORESCENCE: A spike - erect, continuous with the rachis, and 4-20 cm long. Internodes are less than 10 mm apart. Spikelets usually one per node, but sometimes are two, 10-29 mm long, and with 4-9 florets. Glumes are shorter or as long as floret, rigid, and gradually long-tapering from the base to a narrow sharp tip; tip is acuminate and often curved. Lemmas are awn-tipped or with an awn up to 5 or 10 mm. Sources: Barkworth in FNA 2007; Lesica et al. 2012.

At initial appearance Elymus triticoides appears similar to Agropyron smithii.

Western Wheatgrass - Elymus smithii, native
*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 from Agropyron).
*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 and Elymus 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.

Leymus 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.

Pseudoroegneria 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.

Open dry settings, often where historically disturbed (Lavin in Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).