Flora of the Canadian Arctic Archipelago

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S.G. Aiken, M.J. Dallwitz, L.L. Consaul, C.L. McJannet, R.L. Boles, G.W. Argus, J.M. Gillett, P.J. Scott, R. Elven, M.C. LeBlanc, L.J. Gillespie, A.K. Brysting, H. Solstad, and J.G. Harris

Euphrasia L.

English: Eyebright.

Scrophulariaceae, Fernweed family.

Published in Sp. Pl. 604. 1753.

Vegetative morphology. Plants (1.5–)5–10(–20) cm high; annual herbs; not caespitose. Taproot present. Ground level or underground stems absent. Aerial stems erect. Aerial stem trichomes present; retrorse (more or less retrorse). Leaves distributed along the stems; opposite; dying annually and non-persistent. Petioles absent. Leaf blade bases attenuate (sometimes almost petiolate). Blades 2–11 mm long, 3–8 mm wide, spreading or divaricate, obovate or spatulate, flat, veins palmate. Blade adaxial surface glabrous. Blade abaxial surface without sessile glands or glandular hairs (on the blade surfaces hairs on the margins), glabrous. Blades lobed. Leaf primary lobes ovate-lanceolate to obovate-lanceolate, all lobes pointing forwards. Blade margins serrate or crenate or dentate, with non-glandular hairs or with glandular hairs, with teeth toward the base; apices acute, or obtuse, or rounded.

Reproductive morphology. Flowering stems two or more per plant. Flowering stems circular or oval in cross section. Flowering stems with leaves. Flowering stems hairy. Flowering stems pilose. Flowering stem hairs simple; shorter than the diameter of the flowering stem; white or translucent; glandular hairs absent. Inflorescences spicate; elongating as the fruit matures (slightly). Pedicels absent. Involucral bracts absent (floral leaves associated with each flower). Flowers per inflorescence (2–)3–5; bilaterally symmetrical (zygomorphic). Sepals conventional; 4; fused; 3.5–6 mm wide; green. Calyx tubular; 4-lobed; hairy. Calyx hairs non-glandular; white or translucent. Calyx margins ciliate. Calyx teeth equal or nearly so; 1.4–2.6 mm long. Petals conventional; fused; 5; white, or pink, or purple; with contrasting markings (white or purple marked with deep violet lines and with yelllow spots on lower lip and throat); 4–8 mm long. Corolla bilabiate; 4-lobed. Stamens 4; stamen filaments markedly unequal in length (didynamous); free of the corolla. Anthers 0.6–1 mm long (anthers with parallel loculi, spurred, one loculus with a longer spur than the other). Ovary superior; carpels 2; syncarpous. Ovaries ovate, or oblong; hairy. Ovary hairs white; spreading; straight. Styles 1; 3.3–4.5 mm long; straight. Stigmas per ovary 1. Placentation axile. Ovules per ovary numerous. Fruit sessile; with calyx persisting; dry; a capsule; oblong; brown; hairy; surface appearing veinless; not distinctly flattened; dehiscent; splitting to the base into separate segments. Seeds numerous; surfaces smooth, ridged.

Chromosome information. 2n = 44.

Ploidy levels recorded 4x.

North American distribution. Nunavut Islands. Range in the Canadian Arctic Archipelago limited. Rare. Low Arctic, alpine. Arctic islands: Baffin.

General notes. Yeo (1972), in the treatment of the genus Euphrasia for Flora Europaea, indicated that the genus is one of annual (rarely perennial) hemi-parasitic herbs. Flowers are zygomorphic, in bracteate, terminal, spike-like racemes. Bracts (floral leaves) are large and leaf-like; bracteoles are absent. Yeo (1972) stated that most of the species are very variable and weakly differentiated. They hybridise readily, and the taxonomy of the genus is therefore difficult. Populations frequently occur in which one character falls outside the normal range of variation, and hybrids sometimes occur independently of the parents as well as commonly with them.

Yeo (1972) noted that although with sufficient experience it is possible to assign the great majority of populations to a species, it is extremely difficult to provide rigidly diagnostic descriptions. The most important taxonomic characters are length of internodes, node at which the lowest flower is situated, number of branches, shape, size and indumentum of leaves, size of corolla, shape, size, and indument of capsule. He did not consider the presence or absence of eglandular or short glandular hair as very important, although he suggested the presence or absence of long glandular hairs is.

Fernald and Wiegand (1915) distinguished the two species that occur in the Canadian Arctic Archipelago using the following characters. Both species have a spicate inflorescence that becomes loose and elongate; flowers 4–10 mm long; bracts with acute teeth; corollas with the upper lip plainly bilobed; the lobes somewhat reflexed from the base (but not revolute);

E. disjuncta Internodes long; inflorescence open, the lowest bracts spreading at maturity, 2–5 cm apart, corolla 4–5(-6) mm long.

E. wettsteinii Internodes short; inflorescence dense above, the lowest bracts ascending at maturity; corolla 5–7 mm long.

The specimens from the Canadian Arctic Archipielago are small plants. The length of the corolla is one of the better characters for distinguishing species.

Elven (personal communication, 2005) noted that in an arctic context this complicated genus is most varied in the amphi-Atlantic regions of Europe and northeastern North America. Even if large parts of the genus have been revised several times by, e.g., Wettstein (1896), Jørgensen (1919), Pugsley (1930, 1936), Sell and Yeo (1970), Yeo (in Tutin et al. 1972), and Gussarova (2005), many problems remain, not least when comparing across countries and regions.

&#;Alaska and Canada.&#;none Two clearly different species were recognised for Alaska and Yukon Territory by Hultén (1968a, 1968b): the small-flowered and eglandular E. mollis (Ledeb.) Wettst. as amphi-Pacific but as non-arctic on the Asian side; and the even more small-flowered and long-stipitate glandular E. disjuncta Fernald and Wiegand, with E. subarctica Raup given as a synonym. Hultén considered E. disjuncta to be 'trans-American' and later also included E. hudsoniana Fernald and Wiegand and the other eastern Canadian plants in arctic Labrador, Ungava, and in Baffin Island within this species. Sell and Yeo (1970) had a rather different view in their revision of North American Euphrasia. They recognised several species for the northern parts, the amphi-Pacific E. mollis, several exclusively American ones, and some amphi-Atlantic ones (native and/or introduced). Their treatment is followed in Elven et al. (2003) and implies seven arctic North American species: E. curta as eastern, possibly introduced; E. disjuncta as eastern; E. frigida (= E. wettsteinii) as northeastern; E. hudsoniana as eastern; E. mollis as western, Pacific; E. subarctica as northwestern; and E. vinacea P.D. Sell and Yeo as Hudsonian. Scoggan (1979) accepted eight Canadian species of the genus but only two as relevant for the arctic parts: E. arctica (in which he included, e.g., E. disjuncta, E. frigida auct., and E. subarctica) and E. hudsoniana. He noted the "widely different treatments by North American and British authors" of this genus. That especially concerns his concept of E. arctica, which includes very disparate elements, none of them very close to E. arctica as originally described.

The current treatment of Euphrasia is still unsatisfactory and insufficient for some regions, in spite of the numerous and thorough systematic studies.


This publication is available on the internet (posted May 2011) and on CD-ROM (published in 2007). These versions are identical in content, except that the errata page for CD-ROM is accessible on the main index page of the web version.

Recommended citation for the web-based version of this publication: Aiken, S.G., Dallwitz, M.J., Consaul, L.L., McJannet, C.L., Boles, R.L., Argus, G.W., Gillett, J.M., Scott, P.J., Elven, R., LeBlanc, M.C., Gillespie, L.J., Brysting, A.K., Solstad, H., and Harris, J.G. 2007. Flora of the Canadian Arctic Archipelago: Descriptions, Illustrations, Identification, and Information Retrieval. NRC Research Press, National Research Council of Canada, Ottawa. http://nature.ca/aaflora/data, accessed on DATE.

Recommended citation for the CD-ROM version of this publication: Aiken, S.G., Dallwitz, M.J., Consaul, L.L., McJannet, C.L., Boles, R.L., Argus, G.W., Gillett, J.M., Scott, P.J., Elven, R., LeBlanc, M.C., Gillespie, L.J., Brysting, A.K., Solstad, H., and Harris, J.G. 2007. Flora of the Canadian Arctic Archipelago: Descriptions, Illustrations, Identification, and Information Retrieval. [CD-ROM] NRC Research Press, National Research Council of Canada, Ottawa.

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