Flora of the Canadian Arctic Archipelago
English: Thyme-leaf saxifrage.
Saxifragaceae, Saxifrage family.
Published in Fl. Amer. Sept. 1: 310. 1814.
Type: Alaska: "On the north-west coast", Cape Newenham, leg. D. Nelson. Holotype: BM.
Synonymy. Leptasea serpyllifolia (Pursh) Small, N. Amer. Fl. 22, 2: 152. 1905.
Vegetative morphology. Plants 1–5 cm high; perennial herbs. Taproot present (from each rosette in a mat). Horizontal stems at ground level, branching extensively to shape plant habit as mats (loosely formed). Caudex absent. Aerial stems erect. Leaves present; not heterophyllous; distributed along the stems; alternate; dying annually and non-persistent. Petioles absent. Leaf blades simple. Leaf blade bases truncate, or attenuate. Blades 2–8.5 mm long, 0.4–1.6 mm wide, linear or oblanceolate or oblong, flat, with inconspicuous veins. Blade adaxial surface glabrous. Blade abaxial surface glabrous. Blades not lobed. Blade margins entire; apices obtuse, or rounded.
Reproductive morphology. Plants monoecious. Flowering stems with leaves. Flowering stem hairs simple; shorter than the diameter of the flowering stem; white or translucent, or brown; glandular hairs present. Flowers solitary. Flowers medium-sized; unisexual. Sepals conventional; 5; free; 1.2–1.8 mm long; 2.7–3.4 mm wide; purple, or red; herbaceous (or slightly fleshy). Calyx glabrous (usually, but occasionally with 1–2 glandular hairs). Petals conventional; free; longer than the calyx; 5; yellow; unlobed; 4–8 mm long; 3–4 mm wide. Stamens 10; stamen filaments glabrous. Anthers yellow; ovoid, or sub-globose; 0.5–0.6 mm long. Nectaries present. Receptacle 0.1–0.2 mm high (almost flat). Ovary superior; carpels 2; partly fused. Ovaries glabrous. Placentation axile. Ovules per ovary many. Fruit with calyx persisting; dry; a capsule (no fully developed fruits have been found in Arctic Island collections); ovoid (flask-shaped; see illustration in Porsild and Cody (1980) p. 398); brown (sometimes turning black); 5–8 mm long; 2–3 mm wide; glabrous; dehiscent; splitting to the base into separate segments. Seeds no fully developed seeds have been examined; surfaces smooth (when young).
Chromosome information. 2n = 16.
(2n) (2x) = 16. Zhukova (1967, 1982, northeastern Asia); Zhukova and Petrovsky (1987a, northern and northeastern Asia).
Ploidy levels recorded 2x.
Ecology and habitat. Mostly on gravelly scree slopes.
North American distribution. Alaska, Yukon, continental Northwest Territories, Nunavut Islands (or NWT Islands?). Range in the Canadian Arctic Archipelago limited. Rare. Arctic. Arctic islands: Parry islands (Melville Island: these occurrences in Melville are isolated from the main part of the species distribution (west of Mackenzie River) by about 1,000 km).
Northern hemisphere distribution. Amphi-Beringian. Kharaulakh, YanaKolyma, West Chukotka, Wrangel Island, South Chukotka, East Chukotka, West Alaska, North Alaska Yukon, Central Canada.
General notes. The northernmost record, and first collection from the Arctic Archipelago, is from Melville Island, Sabine Peninsula, Barrow Dome, 76°38'N, 109°05'W, 21 July 1971, M. Kuc 157 (Canada). There have been three other collections from different places on Melville Island. This tiny plant is easily overlooked and is probably under-collected. Plants found in Canada belong to subsp. serpyllifolia. It is an Amphi-Beringian mainly arctic subspecies with glabrous leaves on the vegetative shoots and yellow flowers. Transitional forms to subsp. glandulosa, with slightly pubescent leaves on the vegetative shoots, can be found rarely in the lower reaches of the Lena river and in the southern regions of the Siberian part of the area (Zhmylev, in Elven et al. 2003).
Illustrations. • Habit. Left, plant with tightly clustered simple leaves, flowering stems with leaves and flowers borne singly. Right, flower setting fruit with two diverging carpels, the remnants of anther filaments, and sepals. Porsild and Cody 1980. • Close-up of plant. Tiny plants from creeping rhizomes. CAN 361039. • 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..