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Life span

Perennial, moderately long-lived.

Growth form

Solitary or weakly mat-forming herb with a central root and stems extensively branched at or below ground level (often inside a moss carpet), probably rooting. Numerous short, vegetative shoots in loose or very loose tussocks. Withered leaves are sometimes retained but less so than in Minuartia biflora and M. rubella in Svalbard. Flowering stems ascending or erect, 3–7(10) cm, with 2–3 pairs of stem leaves. The entire plant is glabrous.

Leaf

Leaves opposite, 4–8 mm, linear, obtuse, without distinct sheaths and petioles, with a distinct mid vein but no lateral veins (i.e., ‘one-veined’), dark green or purplish.

Inflorescence

Flowering shoots with a single terminal flower or 2–3(4) flowers in an open dichasial cyme. Flowers on pedicels 1.5–2(3) cm.

Flower

Flowers radially symmetric with 5 free sepals and petals. Sepals 2.5–2.8 × 0.8–1.1 mm, lanceolate, acute or acuminate, with 3 indistinct veins, green or purplish with a narrow, white hyaline margin. Petals 2.5–3.5 × 1.0–1.3 mm, as long as or slightly longer than sepals, oblanceolate, entire, white. Stamens 10. Gynoecium of 3 carpels with 3 stigmas.

Fruit

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

Reproduction

Sexual reproduction by seeds; very local vegetative reproduction by branches rooting in a moss carpet. Flowers small and probably not adapted to insect pollination; self pollination assumed to prevail. The plant flowers and set mature fruits in Svalbard but its extreme rarity suggests that reproduction is not very efficient.

No special adaptations 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.

Within Minuartia, M. stricta can be confused with M. rossii and glabrous forms of M. rubella. It differs from M. rubella in its much longer pedicels and especially in having 1-veined leaves and only indistinct veins on the sepals, whereas M. rubella has markedly 3-veined leaves (especially distinct on withered leaves) and 3 marked, rib-like veins on the sepals (also best visible when withered). The main difference between M. rossii and M. stricta is that M. rossii usually reproduces by bulbils formed as apices of vegetative shoots; such bulbils are never found in M. stricta. However, there are populations of M. rossii, in Svalbard and elsewhere, that flower and do not produce much bulbils. Such plants may be difficult to keep apart from M. stricta (and have resulted in numerous misidentifications). Lid noted on a herbarium sheet in 1969 the following useful character: "M. rossii has more obtuse sepals, less marked sepal veins, and sepals not above 2.2 mm, and in addition very short internodes. [Translated here.]" The long internodes and especially the long pedicels are significant characters to differentiate M. stricta from all other Minuartia in the North Atlantic regions.

Habitat

The few plants found in Svalbard were growing in moss carpets in rather moist sites, in all known sites on basic substrates. The species probably demands a good snow cover and moisture available throughout most of the growth season.

Distribution

Minuartia stricta has been confirmed from Spitsbergen from Ossian Sarsfjellet at Kongsfjorden (Haakon VII Land), Nathorstdalen at Dicksonfjorden (Dickson Land) and Estheriahaugen near Pyramiden at Billefjorden (Dickson Land), these two in the Isfjorden area, and from Flatøyrdalen on the east side of Wijdefjorden (Ny-Friesland). Other reports are not yet confirmed. All four confirmed localities are within the middle arctic tundra zone and the weakly or clearly continental sectors.

This is a circumpolar species but mostly replaced by M. rossii in the northernmost zones of the Arctic.

Comments

See Minuartia rossii.

Literature

No cited literature