Canary grass

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Code: g71
Latin name: Phalaris arundinacea
Source material: Pollen
Family: Poaceae (Gramineae)
Sub family: Pooideae
Tribe: Aveneae
Common names: Reed Canary grass, Reed Canarygrass, Ribbon grass, Variegated grass.

Commonly recognised varieties include:

P. canariensis - Canary grass, Canarygrass (UK), Canary Seed, Canaryseed, Canary Bird Seed;

P. aquatica - Bulbous Canary grass, Harding grass, Hardinggrass (Canada), Toowoomba Canary grass (Australia);

P. coerulescens - Blue Canary grass.


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

Allergen Exposure

Geographical distribution

Canary grass, probably native to North America, is widely distributed in both North America and Europe in regions above the sub-tropics. The European cultivars for hay and forage have no clear distinguishing characteristics from apparently native plants.

Canary grass is a perennial that can grow as tall as 2.6 m, but usually reaches a height of only 1.5 m. The sturdy, often hollow stems can have some reddish coloration near the top. Leaves are up to 30 cm long and 2 cm wide. The seed-head is a compact, green or light-purple panicle that can vary in length from 7 to 40 cm. Panicles are on culms high above the leaves. The plant reproduces sexually by seed production, but spreads mainly vegetatively by means of dense, vigorous rhizome growth

The species flowers between April and September. The flowers are hermaphrodite (have both male and female organs) and are pollinated by wind. The plant is noted for attracting wildlife.

Bulbous canary grass (P. aquatica) pollens represent major sources of allergenic proteins in southern Australia, especially in Victoria (1).


A wetland plant, this species typically occurs in soils that are saturated or nearly saturated for most of the growing season. Ideal conditions typically occur in roadside ditches, rights-of-way, river dikes and levees, shallow marshes, and meadows. It usually forms monotypic stands and is highly competitive with Timothy (Phleum pratense), Meadow grass (Poa pratensis), and Redtop (Agrostis alba). It is also cultivated as a ground cover, and some varieties are used ornamentally.

Unexpected exposure

The leaves have been woven into hats and mats.

The closely related genus members P. aquatica (perennial pasture grass) and P. paradoxa (paradoxa grass) have been associated with the poisoning of sheep and horses (2, 3). The leaves of P. aquatica contain two groups of known toxins, indole alkaloids, primarily dimethyltryptamines and N-methyltyramines, which cause illnesses in grazing animals, especially sheep (4).

Allergen Description

No allergen(s) have been characterised:

No allergens have been characterised from this grass, but several protein allergens have been isolated from the closely-related Bulbous canary grass (P. aquatica) pollen (5), suggesting a possible inference of allergens that may be present in P. arundinacea:

Pha a 1, a 34 kDa protein, a major allergen (6)

Pha a 5, a major allergen, and 4 isoforms (6)

IgE binding of Pha a 1 was investigated in 24 sera of Bulbous Canary grass-allergic individuals and found in 19 of 24 (5).

Potential Cross-reactivity

Extensive cross-reactivity among the different individual species of the genus can be expected, and to a certain degree among members of the family Poaceae; in particular, grasses belonging to the Pooideae sub-family (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)) (7, 8).

Allergens have not been characterised in Canary grass, but from the potential inference of allergens found in Bulbous Canary grass, the following potential cross-reactivities may occur.

Bulbous Canary grass contains Group 1 allergens, to which more than 95% of patients allergic to grass pollen possess IgE antibodies. These are highly cross-reactive glycoproteins exclusively expressed in the pollen of many grasses (9-11). Group 1 allergens are highly homologous, but not all of the antigenic epitopes are cross-reactive (12). For example, Group 1 allergens from eight different clinically important grass pollens of the Pooideae (Rye grass, Canary grass, Meadow grass, Cocksfoot and Timothy), Chloridoideae (Bermuda grass) and Panicoideae (Johnson grass, Maize) were isolated, and IgE binding to an allergic human serum pool was conducted to determine the degree of antigenic and IgE-binding similarities. The highest IgE-binding similarity was observed between Cocksfoot and Rye grass (53%) and between Rye grass and Canary grass (43%). No IgE-binding similarity was observed between Maize and other grasses. The highest antigenic similarity was also observed between Rye grass and Cocksfoot grass (76%), and the lowest similarity between Maize (23%) and Bermuda (10%) (13).

Highly homologous Group 1 allergens have been demonstrated between Pha a 1 from Canary grass, Lol p 1 from Rye grass pollen (a deduced amino acid sequence identity of 88.8%), Hol l 1 from Velvet grass pollen (88.1%), and Phl p 1 from Timothy grass pollen (86.6%) (6). The major Timothy grass pollen allergen Phl p 1 also cross-reacts with most grass-, Corn- and monocot-derived Group 1 allergens (14). Monoclonal antibodies of Cyn d 1 (Bermuda grass) recognised cross-reactive epitopes on proteins from eight other grasses including Rye grass, Timothy grass, Meadow grass and Johnson grass (15).

Pha a 1 from Bulbous Canary grass (P. aquatica) has been shown to have common allergenic components with other grasses, with the amino acid sequence of this protein showing > 90% identity to that reported for Rye grass allergen Lol p 1, and other group 1 allergens from Timothy and Kentucky bluegrass pollens (6, 16, 17). IgE binding of Pha a 1, Lol p 1 (Ryegrass), and Cyn d 1 (Bermuda grass) was investigated in 24 sera of Bulbous Canary grass-allergic individuals and found to occur in 19 of 24, 18 of 24, and 9 of 24, respectively. IgE binding to all three major allergens, or to both Pha a 1 and Lol p 1, occurred in 8 of 24 sera. The findings suggest that while the N-terminal sequence of Pha a 1 was identical to Lol p 1, there may be specific allergenic epitopes exclusive to this allergen that are important for allergenicity in southern Australia (5). As P. aquatica and P. arundinacea are closely related, this may apply to the latter grass pollen as well.

Bulbous Canary grass pollen contains a Group 5 allergen. Almost 90% of grass pollen-allergic patients are sensitised against Group 5 grass pollen allergens. A monoclonal human IgE antibody has been shown to cross-react with Group 5A isoallergens from several grass and Corn species (18). Polymorphic forms of Pha a 5 from Canary grass have been shown to share significant sequence identity with other group 5 allergens from Ryegrass, Timothy and Meadow grass pollens (6). Group 5 allergens have been detected in Phleum pratense, Lolium perenne (Ryegrass), Poa pratense (Meadow grass) and Dactylis glomerata (Cocksfoot) extracts. The major components in these fractions were found to be 25 to 28 kDa proteins, and IgE binding to these components was confirmed using a pool of grass-allergic sera (19).

Antibodies eluted from the major Ryegrass pollen allergens, Lol p 1 and Lol p 5, showed IgE reactivity with allergens of Ryegrass and Canary but not Bahia or Bermuda grasses. Timothy, Canary and Ryegrass inhibited IgE reactivity with Ryegrass and Bahia grass, whereas Bahia, Johnson and Bermuda grass did not inhibit IgE reactivity with Ryegrass (20).

Sequence comparisons showed that the Hor v 9 cDNA clones (Barley pollen) were also homologous to Group 5 allergens of Timothy grass (Phleum pratense) pollen and Bulbous Canary grass (Phalaris aquatica) pollen, and to the Group 9 allergen of Ryegrass (Lolium perenne) pollen (21).

Clinical Experience

IgE mediated reactions

Anecdotal evidence suggests that Canary grass (P. arundinacea) pollen, as with Bulbous Canary grass (P. aquatica) pollen, often induces asthma, allergic rhinitis and allergic conjunctivitis in sensitised individuals; however, few studies have been reported to date (18).

Canary grass pollen has been found in aeroallergen studies in the Western Cape, South Africa, and may contribute to sensitisation (22).

Other reactions

RAST of sera from subjects sensitised to wheat and rye flour indicated that there is significant reaction with seed extracts of 12 cereals (Wheat, Durum Wheat, Triticale, Cereal Rye, Barley, Rye grass, Oats, Canary grass, Rice, Maize, Sorghum and Johnson grass) (23).

Occupational contact dermatitis from canary-grass (P. aquatica) seed has been described (24).

Compiled by Dr Harris Steinman, developer of Allergy Advisor,


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