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

Oxytropis podocarpa A. Gray

English: Inflated oxytrope,

French: Oxytrope â gros fruits.

Fabaceae (Leguminosae), Pea family.

Published in Proc. Amer. Acad. Arts 6: 234. 1864.

Type: Canada: "Labrador, Arctic regions, and Rocky Mountains, lat. 49°." selected by Fernald (1928), Schweinitz, s.n. (Welsh 1995). Lectotype.

Synonymy. Oxytropis arctica var. inflata Hooker, Fl. Bor.-Amer. 1: 146. 1831. Type: "Highest summits of the Rocky Mountains., Drummond s.n.," Holotype: K. (paratype of Oxytropis podocarpa, Welsh 1995).

Oxytropis podocarpa var. inflata (Hooker) B. Boivin, Naturaliste Can. 94: 78. 1967.

Vegetative morphology. Plants 2–6 cm high; perennial herbs; caespitose (not as dense as O. nigrescens). Taproot present. Ground level or underground stems absent. Horizontal stems at ground level, branching extensively to shape plant habit as cushions, or mats (looser than O. nigrescens var. uniflora). Caudex present (much branched under the cushions). Aerial stems erect. Aerial stem trichomes spreading. Leaves distributed along the stems; alternate; marcescent. Stipules present; persisting for 2 or more years; 4–5 mm long; 2–3 mm wide; not sheathing (most readily seen among the previous season's growth); brown (pale straw-coloured), or white (after several years); hairy; villous (particularly on the margins); apex obtuse. Petioles 5–12 mm long; hairy; strigose. Petiole hairs longer than the diameter of the petiole; appressed, or spreading; straight. Leaf blades compound. Leaves not grass-like. Blades 7–12 mm long, 6–9 mm wide, veins pinnate. Blade adaxial surface hairy, hairs villous or long-silky (sparse, the upper surface appears greenish), hairs simple, hairs sparse, hairs white, or translucent. Blade abaxial surface hairy, hairs long-silky, hairs very dense (so that surface appears grey), hairs white, hairs straight, hairs appressed. Blade margins slightly revolute (so that that upper grener surface of each leaflet is more evident). Blade apices acute. Leaflet arrangement pinnate. Leaflets (5–)7–13; 2–5 mm long; (0.5–)0.8–1.2 mm wide; linear, or lanceolate (narrowly); veins inconspicuous.

Reproductive morphology. Flowering stems two or more per plant; without leaves. Flowering stems hairy. Flowering stems strigose. Flowering stem hairs simple (pointing towards the flower); white or translucent and black. Flowers solitary (rarely), or in inflorescences (of two flowers). Inflorescences racemose (when two flowers are present); diffuse; elongating as the fruit matures (slightly). Pedicels absent (or very short). Floral scales hairy all over (pilose or viollous and covered with black hairs). Flowers per inflorescence 2 (usually); medium-sized; bilaterally symmetrical (zygomorphic). Sepals conventional; 5; fused; 8.5–9.5 mm wide; brown (bluish hairy). Calyx tubular; 5-lobed; hairy. Calyx hairs pilose, or villous; non-glandular; white or translucent and black. Calyx teeth 2–2.5(–3) mm long. Petals conventional; both free and fused; 5; purple (violet); with contrasting markings (insect guidelines and colour gradation from intense colour at the tips of the petals to pale at the bases); unlobed (four petals), or slightly lobed or undulating (banner petal); 11–16 mm long. Corolla papilionaceous; keel with a pointed tip. Stamens 10; stamen filaments all equal in length (or almost). Anther filaments 9 fused into a tube, plus 1 free. Nectaries present. Ovary superior; carpels 1; monomerous. Stigmas per ovary 1. Ovules per ovary 20–28. Fruit sessile (almost sessile; may appear stalked when there is only a single fruit developed on a long peduncle); with calyx persisting; dry; a legume (on a stalk within the calyx); ovoid; black; 12–20 mm long (? to 30 mm long, Porsild, 1964); 6–10 mm wide; hairy; not distinctly flattened; dehiscent (from the tip of the legume); opening at the apex and partially or fully down one side. Legume unilocular; valves straight. Styles persisting but not modified. Seeds 16–24; 1.5–2 mm long (i.e., the longest dimension); black, or brown; surfaces smooth.

Chromosome information. 2n = 16.

2n (2x) = 16. Ledingham (1960).

Ploidy levels recorded 2x.

Taxon as an environmental indicator. This is a southern species, with the most northern record being from Southampton Island, Salmon Pond, 64°12'N.

Ecology and habitat. Substrates: hummocks, tundra; imperfectly drained moist areas, moderately well-drained areas; gravel, sand (ridges); acidic, or calcareous.

North American distribution. Nunavut Islands, Labrador. Rare. Low Arctic (A rare species of peculiar disrupted range. Known thus far from the Rocky mountains, northern Labrador and southern Baffin Island). Arctic islands: Baffin (Iqaluit, Amajuak Bay), Southampton.

Northern hemisphere distribution. Cordilleran (with disjunct eastern occurrences in S Baffin I. and N Labrador). Labrador – Hudson Bay.

General notes. Porsild (1964) mapped records for Kimmirut and Cape Dorset, but we have found no vouchers to confirm the distributions.

Illustrations. • Herbarium specimen. Flowers with blue petals and blackish calyces. Note the long taproot with many shoots arising from the caudex or root crown. Nunavut, Baffin Island, Iqaluit. 14 July, 1953. V.C. Wynne-Edwards 9310. CAN 223777. • Fruiting plant. Plant with fruit pods that are opening. Nunavut, Baffin Island, Apex, on the hill above the HCB Managers house. 19 August, 2006. Aiken. No Voucher. • Fruiting plant. Tuft less compact than Oxytropis arctobia. Fruiting plant with pods about 1 cm long that eventually split from the apex. J.M. Gillett 820495. • Arctic Island Distribution.


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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