Comparison of Elymus Repens Subsp. Repens and Pascopyrum Smithii Florets

Comparison of Elymus repens subsp. repens and Pascopyrum smithii florets

Seed Science and Technology Section (SSTS), Saskatoon Laboratory, Canadian Food Inspection Agency

Two plant species with similar seed features are compared for their identification: Pascopyrum smithii (ISTA Elymus repens subsp. repens : couchgrass, stabilized name) : western quackgrass or common couch wheatgrass Synonyms: Elytrigia repens (ISTA Synonyms: Agropyron smithii, stabilized name), Agropyron repens , Elymus smithii, Elytrigia smithii Agropyron firmum , Triticum firmum , Triticum Perennial, naturalized in North repens America Perennial, native of Eurasia, exotic to North Commonly used as cultivated America feed for animal, erosion control or Commonly grows in cultivated fields, revegetation pastures, old fields, railway lines, roadsides and disturbed areas Primary Noxious weed on Canada's Weed Seeds Order (2005) of the Seeds Act . Also regulated in some U.S. States.

2 Seed Features for distinguishing and separation

Which floret (seed) is different?

Floret A Floret B Floret C

3 Seed Features for distinguishing and separation

Palea view on rachilla: P. smithii : E. repens :

Wedge-shaped rachilla Parallel sided rachilla V-shaped sinus (in circle) U-shaped sinus (in circle)

4 Seed Features for distinguishing and separation

A B C

Suture area Suture area triangular shaped oval shaped

Floret A&B: Pascopyrum smithii Floret C: Elymus repens subsp. repens Couchgrass Western wheatgrass

5 Features of palea teeth

P. smithii : E. repens : Teeth close together mixed long Teeth are thick and widely spaced & short

6 Features from the view of lemma/callus

P. smithii : E. repens : Depressed line above callus Bump above callus

7 Features from lemma view

P. smithii : E. repens : Depressed straight line above Bump above callus callus

Line of hairs across callus

No hair present

8 Acknowledgement

Thanks to SSTS staff Susan Putz, Jennifer Neudorf, Ruojing Wang for putting the information together and Jo Jones for taking the digital images.