Life span

Perennial, moderately long-lived.

Growth form

Soilitary or weakly mat-forming herb with branched caudex and rooting stems, forming tussocks or small mats with a large number of short, vegetative shoots. Flowering stems 0–3 cm with 1–2 pairs of reduced stem leaves. Stem and base of calyx with minute, articulate hairs, mostly gland-tipped.

Leaf

Leaves opposite, 3–8 mm, linear or very narrowly lanceolate, acute, without distinct sheaths, lamina with distinct, but not raised mid vein (i.e., ‘one-veined’), with minute, mostly one-celled, eglandular hairs. Dead leaves persist, often for several years.

Inflorescence

Flowering shoots with a single terminal flower or two flowers (scientific name: 'biflora' = two-flowered), on pedicels 3–10 mm.

Flower

Flowers radially symmetric with (4)5 free sepals and petals. Sepals 2–3.5 × 0.7–1.5 mm, narrowly elliptic or very narrowly lanceolate, obtuse, with distinct mid vein and often two indistinct lateral veins, often with an uneven (fringed) and narrow hyaline white margin and purplish coloured apex. Petals longer than sepals, 3.5–5.5 × 1–1.5 mm, narrowly oblong, truncate or slightly emarginate at apex, white or rarely pale pink. Stamens 10. Gynoecium of 3 carpels with 3 stigmas.

Fruit

Fruit a one-roomed capsule that opens apically with 3 teeth, with numerous seeds.

Reproduction

Sexual reproduction by seeds; very local vegetative reproduction by rooting branches. Flowers small and probably not adapted to insect pollination; self pollination assumed to prevail. The plant flowers and fruits regularly in Svalbard and regularly produces mature seeds. Seeds did not germinate in an experiment (Alsos et al. 2013) but we assume this to be abnormal.

No special adaptation to seed dispersal.

Comparison

The species of Minuartia can be confused with those of Sagina but differ in having 3 styles and capsule teeth, whereas Sagina has 4–5 styles and capsule teeth. This is not always easily observed, but the shapes of buds, sepals and capsules are usually different. Whereas Sagina has nearly globular buds, short and boat-shaped sepals, and ovoid capsules, Minuartia has elongated buds, lanceolate sepals, and usually more elongated capsules.

Both Minuartia rubella and M. biflora are (mostly) pubescent, whereas M. rossii and M. stricta are (always) glabrous. Minuartia rubella differs from the three others by its three prominent veins in leaves and sepals; the others have at most one prominent vein. The sepals easily differentiate M. rubella from M. biflora; the former has acute to acuminate sepals, the latter obtuse.

Habitat

Grows on moderately dry to moderately moist slopes and similar meadows, usually with snow protection (snowbeds) and stable soil with a humus layer. It often grows intermingled with other plants and mosses. The substrates are fine or coarse (silt to stones) and well-drained. Indifferent as to soil reaction (pH) but perhaps avoids the areas with the most basic soils (i.e., rare in the arctic steppe parts of Wijdefjorden).

Distribution

Common in all zones and sections. Common on Spitsbergen and recorded from all major islands in the Spitsbergen group except for Bjørnøya.

The general range is circumpolar and arctic–alpine and the species is very widespread.

Comments

The genus Minuartia is heterogeneous and polyphyletic (Nepokroeff et al. 2001, 2002) and will in the future probably fall apart into several genera. The Svalbard plants may then be assigned to the genera Tryphane (rubella), Lidia (biflora), and Alsinanthe (rossii and stricta). This also means that, whereas M. rossii and M. stricta are fairly closely related, these two and the two others are only distantly related.

Literature

Alsos, I.G., Müller, E. & Eidesen, P.B. 2013. Germinating seeds or bulbils in 87 of 113 tested Arctic species indicate potential for ex situ seed bank storage. – Polar Biology 36: 819–830. Doi 10.1007/s00300-013-1307-7.

Nepokroeff, M. et al. 2001. Origin of the Hawaiian subfam. Alsinoideae and preliminary relationships in Caryophyllaceae inferred from matK and trnL–C–F sequence data. – In: Botanical Society of America. 2001. Botany 2001 Abstracts: 130.

Nepokroeff, M. et al. 2002. Relationships within Caryophyllaceae inferred from molecular sequence data. – In: Botanical Society of America. 2002. Botany 2002 Abstracts: 105.