Life span

Perennial, comparatively short-lived.

Growth form

Solitary herb with a very short caudex with a fascicle of short, pale yellow roots and a single rosette of leaves. Winter survival as leafy buds. Usually a single new bud is produced on top of the caudex beside the rosette during the season. Scapes (without leaves) from the rosette, 1–2(3) on each plant, 1.5–3 cm long, glabrous, dark reddish at base, pinkish green towards the flower. Each scape bent over at the very top and with a single flower.

Leaf

Leaves alternate, 4–5 in a single rosette up to 4 cm in diameter, more or less prostrate to the ground. Leaves 1.3–1.7 × 0.5–1 cm, ovate to oblong with involute margins, with distinct mid vein and less distinct reticulum of lateral veins, yellowish green to tinted pink, with numerous short-stalked, sticky yellow glands on the upper surface.

Inflorescence

See Growth form. Scapes with single flowers.

Flower

Flowers monosymmetric. The bend of the uppermost part of the scape turns the flower upside down; what we see as lower and upper lips in the flower are developmentally the opposite. We here describe the flower as it appears in nature (i.e., the wrong way). Calyx green to tinted pink, fused but deeply split into two lips. The lower lip has 2 more or less deep lobes from two sepals, the upper lip has 3 irregular, shallow lobes from 3 sepals. Corolla fused, two-lipped, cream white with a large yellow patch on the lower lip and in the throat. The lower lip 3-lobed, 9–10 × 6–8 mm, with a broad mid-lobe and 2 more narrow lateral lobes at an angle of ca. 45–60° with the mid lobe, with a raised central part of the mid-lobe strongly yellow and with sticky hairs (glandular), and with a short conical spur at base, 2–3 mm long, yellow to brownish. The upper lip 2-lobed, 7–8 × 4–5 mm. Stamens 2, inserted in the throat (corolla tube) and appearing at its mouth. Gynoecium of 2 fused carpels with a single style.

Fruit

Fruit a one-roomed rounded capsule opening by 2 valves, with numerous (up to 100), very small seeds.

Reproduction

Sexual reproduction by seeds; no vegetative reproduction. Pinguicula alpina is strictly adapted to insect pollination and cross-fertilization (allogamy). This plant must flower and set seed regularly at its Svalbard site. It is present in a quite large population (more than 1000 individuals; Eidesen et al. 2013), have a risky winter survival by a single small bud at the soil surface, susceptible to soil disturbance (e.g., by frost), and the single individuals can not live for long, probably less or much less than 10 years. In other species of Pinguicula, also the roots die off in winter but P. alpina is reported to retain its roots.

Seeds are very small and light and probably only dispersed by wind.

Comparison

There is nothing even remotely similar in the flora of Svalbard.

Habitat

Eidesen et al. (2013, translated here). "... south-facing a little up the valley slope (ca 70 m a.s.l.) ... population ... stretching across a seepage area dominated by moss tundra, with several Carex spp. (C. parallela, C. maritima, C. misandra) and Coptidium lapponicum. The population also extends to drier areas with Dryas octopetala and Cassiope tetragona."

Distribution

Strongly thermophilous. Known from a single population in Ringhorndalen, an E–W running tributary valley to the S–N running major fjord Wijdefjorden in Ny-Friesland in N Spitsbergen. The plant was first found here in 2012 (Eidesen et al. 2013), in a population of more than 1000 individuals. The south-facing slopes, cliffs and screes of Ringhorndalen and neighboring valleys harbor the probably largest concentration of thermophilous and/or xerophilous vascular plants in Svalbard. The site is located in the middle arctic tundra zone (zone C in Elven et al. 2011) and in the clearly continental section.

Pinguicula alpina is a European and W Siberian species widely distributed in boreal and alpine areas. In the Arctic, it is frequent in the southernmost zone (E, the shrub tundra zone) but barely transgresses into the southern arctic tundra zone (zone D). The population in Ringhorndalen is by far the northernmost known in the world, and the distance to its nearest localities (in mainland N Norway) is 900–1000 km.

Comments

Pinguicula alpina is the only insectivorous plant known from Svalbard. The sticky leaves catch insects that land on them (the yellow glands on the surface looks like something edible). After an insect has landed, the leaf margins turn inward and close over the insect, and the enzymatic digestion commences. After the meal, the leaf opens again. Pinguicula alpina is a semi-parasite; it also has chlorophyll and gets nutrients from photosynthesis. Whether the insect catch is rich in Ringhorndalen we don't know but the valley is probably among the sites in Svalbard with the richest insect fauna with numerous individuals.

Eidesen et al. (2013) assume (translated here): "that it is highly probable that the vegetation we find in the southfacing slopes of Ringhorndalen is remains from a more thermophilous vegetation with a larger distribution in Svalbard during the warmest periode [the Hypsithermal] after the last glaciation (ca. 9000–5000 years ago; Hyvärinen 1970, Birks 1991, Miller et al. 2010)." We share this view, and we also understand the reluctance of Eidesen et al. to state categorically that Pinguicula alpina has a similarly long history. A lucky long-distance dispersal to Ringhorndalen some hundreds or perhaps thousands of years ago and sustenance of a population since is also a feasible hypothesis. However, we would rather go for the relict hypothesis in this case.

Literature

Birks, H.H. 1991. Holocene vegetational history and climatic change in west Spitsbergen – plant macrofossils from Skardtjørna, an Arctic lake. – The Holocene 1: 209–218.

Eidesen, P.B., Strømmen, K. & Vader, A. 2013. Fjelltettegras Pinguicula alpina funnet ny for Svalbard i Ringhorndalen, Wijdefjorden, en uutforsket arktisk oase. – Blyttia 71: 209–213.

Elven, R., Murray, D.F., Razzhivin, V. & Yurtsev, B.A. (eds.) 2011. Annotated Checklist of the Panarctic Flora (PAF).

Hyvärinen, H. 1970. Flandrian pollen diagrams from Svalbard. – Geografiska Annaler, Ser. A, Physical Geography 52: 213–222.

Miller, G.H., Brigham-Grette, J., Alley, R.B., Anderson, L., Bauch, H.A., Douglas, M.S.V., Edwards, E., Elias, S.A., Finney, B.P., Fitzpatrick, J.J., Funder, S.V., Herbert, T.D., Hinzman, L.D., Kaufman, D.S., MacDonald, G.M., Polyak, L., Robock, A., Serreze, M.C., Smol, J.P., Spielhagen, R., White, J.W.C., Wolfe, A.P. & Wolff, E.W. 2010. Temperature and precipitation history of the Arctic. – Quaternary Science Review 29: 1679–1715.