Wild rye grass

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Code: g70
Latin name: Elymus triticoides
Source material: Pollen
Family: Poaceae (Gramineae)
Sub family: Pooideae
Tribe: Triticeae
Common names: Wild Rye, Beardless Wildrye, Creeping Wildrye, Alkali Ryegrass, Squaw grass, Beardless Lyme Grass

Synonyms: Leymus triticoides, Elymus condensatus

There is a need to differentiate between Cultivated Rye grass pollen (Secale cereale) g12, Rye the foodstuff (Secale cereale) f5, Rye grass (Lolium perenne) g5, and Wild Rye grass (Elymus triticoides) g70.

Pollen

A grass species producing pollen, which often induces hay fever, asthma and conjunctivitis in sensitised individuals.

Allergen Exposure

Geographical distribution

This grass is native to and widespread in western North America, from Washington State to California, and east to Montana. It often forms large clumps in the wild, but is also grown for forage and ground cover, especially for erosion control in low- and medium-elevation saline and alkali areas. In Europe the closely-related species Lymegrass (E. arenarius) is common in the dunes along coasts.

Wild Rye grass looks like a cross between Bermuda grass and Salt grass. It is a cool-season perennial, forming extensive creeping rhizomes. The stems are upright, hollow, usually unbranched, and up to 1.2m tall. Blades are up to 10cm long, about 1cm wide, flat to involute, at least somewhat stiff, and rough to the touch. The inflorescences are spikes up 25cm long, mostly 2 per node, with spikelets containing 3 to 8 flowers each.

It flowers between June and August, and the seeds ripen from September to October. The flowers are hermaphrodite (have both male and female organs) and are pollinated by wind. Seed germination (requiring cold) is poor. Seedlings are weak and compete poorly with weeds and other grasses in the early developmental stages. However, once established, the grass is very rhizomatous and maintains stands for many years.

This grass is unlike most others in the genus Elymus because of its very slender and short spikes, its long-creeping rhizomes, and its paired spikelets.

Environment

Meadows, damp ravines, river flats, sand dunes, often in salty areas; erosion-prone slopes; cultivated beds.

The seed may be ground into flour and used to make to make bread, cakes, or porridge. (The hairs on the seed must be removed, traditionally by singeing, before consumption.)

Unexpected exposure

The leaves are used for making mats, rope, paper, baskets, etc.

Allergen Description

No allergens from this plant have yet been characterised.

Potential Cross-reactivity

The pantemperate tribe Triticeae is notable for its cereal genera: Wheat, Barley and Rye. The close relation speaks in favour of cross-reactivity between Wild Rye grass g70, Cultivated Wheat g15, Cultivated Rye grass g12, Barley g201, and Couch grass (Agropyron repens), as well as Lymegrass (Elymus arenarius). Extensive cross-reactivity among the different individual species of the genus may be expected. There should be cross-reactivity with other members of the family Poaceae, particularly in the subfamily Pooideae (Rye grass (g5), Canary grass (g71), Meadow grass (g8), Timothy (g6), Cocksfoot (g3), Meadow Fescue (g4), Velvet (g13), Redtop (g9), Meadow Foxtail (g16), Wild Rye grass (g70)) (1, 2).

Clinical Experience

IgE-mediated reactions

Anecdotal evidence suggests that Wild Rye grass pollen may induce asthma, allergic rhinitis and allergic conjunctivitis in sensitised individuals; however, no studies have been reported to date.

In Missouri, USA, the close relative E. canadensis (Canada wildrye or Canada wild rye) has been implicated as a minor contributor in hay fever, and other genus members have been suspected elsewhere, particularly in California (3).

Compiled by Dr Harris Steinman, developer of Allergy Advisor, http://allergyadvisor.com

References

  1. Yman L. Botanical relations and immunological cross-reactions in pollen allergy. 2nd ed. Pharmacia Diagnostics AB. Uppsala. Sweden. 1982: ISBN 91-970475-09 
  2. Yman L. Pharmacia: Allergenic Plants. Systematics of common and rare allergens. Version 1.0. CD-ROM. Uppsala, Sweden: Pharmacia Diagnostics, 2000.

As in all diagnostic testing, the diagnosis is made by the physican based on both test results and the patient history.