Saussurea alpina

GROWTH FORM

Mat-forming herb with stout horizontal rhizome, 0.4–0.5 mm thick, covered by dark brown withered leaf sheaths, and vertical, stout caudex branches ending in leaf rosettes. Stems erect, 5–10(15) cm long, 4–5 mm thick, with ridges but without wings, unbranched below the inflorescence, pubescent with arachnoid hairs (very thin and intertwined like cobweb), brownish red or purple. Several stem leaves decreasing in size and especially in width upwards on stem.

LEAF

Leaves alternate. Basal and lower stem leaves with a broad sheath clasping the base of the stem. Petiole up to 2 cm, winged. Blade 3–5 × 1.5–2 cm, lanceolate with cuneate base, subacute apex, and margins entire or sparsely but coarsely dentate, upper surface dark green and glabrous or with sparse, arachnoid hairs, lower surface very pale green and with dense, arachnoid hairs, with veins glabrous and dark (purple). Upper stem leaves very narrow, with short petioles or sessile.

INFLORESCENCE AND FLOWER

The primary inflorescence of Asteraceae is a head (capitulum) surrounded by an involucrum of one or more rows of phyllaries (involucral bracts). The flowers sit on a flat, concave or convex receptacle, sometimes with scales (the bracts of the single flowers). The flowers are epigynous with perianth at top of the gynoecium. The sepals are always transformed into a pappus, mostly by hairs or sometimes by scales. The 5 stamens are inserted in the corolla tube and the anthers form a ring through which the style grows and pushes the pollen outwards. Gynoecium of two fused carpels, 2 stigmas. The fruit is an achene with one seed.

Inflorescence a dense, bracteate corymb of often 5–8 heads. Heads ovoid or cylindrical, 1–1.5 × 0.5–0.7 cm. Phyllaries in 3–5 rows, densely imbricate, ovate or oblong, obtuse, with an appendage, dark greyish violet, densely hairy. Receptacle with scales. 10–15 flowers per head. Flowers of one kind, bisexual, radially symmetric with tubular corolla with 5 linear lobes, purple.

FRUIT

Fruit (not observed in Svalbard) with 4 ridges, glabrous, with pappus in 1–2 rows, the outer row of short, slightly scabrous hairs falling off early, the inner row fused at base as a ring, with long, white, plumose (feathery) hairs. Numerous fruits from each head.

REPRODUCTION

Sexual reproduction by seeds. Pollination and seed reproduction may have taken place on Bjørnøya but probably never on Spitsbergen; local vegetative reproduction by fragmentation of rhizome. Insect pollinated; insects are attracted by a strong, pleasant vanilla smell. Strictly cross pollinated.

COMPARISON

There is nothing similar in the Svalbard flora.

HABITAT

In a damp tundra on Bjørnøya. On Spitsbergen only found by a cabin and probably originally planted, now well established by vegetative means.

DISTRIBUTION

Native on Bjørnøya, found in 2022 on the southern part of the island, far from cabins and other human influence. Introduced on Spitsbergen, and here only known from a single locality by a cabin on the southwest coast of Spitsbergen at Kapp Berg south of Storvika, Wedel Jarlsberg Land. The locality on Bjørnøya is situated in the middle arctic tundra and the weakly oceanic sector, than on Spitsbergen in the northern arctic tundra zone and the transitional section.

Saussurea alpina is otherwise a widely distributed, arctic–alpine plant of Europe and NW Siberia, reaching south to the C European mountains.

COMMENTS

Saussurea alpina is a very hardy plant that reaches 2130 m a.s.l. in the Norwegian mountains (Elven et al. 2022). It is one of the 20 most hardy, high alpine plants of Scandinavia and should be able to survive well into the middle arctic tundra zone in Svalbard, perhaps also in the northern arctic zone, but some other factor may be limiting it to its only known native site in the southern parts of Bjørnøya, where it was first found in 2022. It flowers late also in Scandinavia, and if flowering is governed (more or less) by day length, the long-day conditions in Svalbard, lasting well into August, may prevent flowering before autumn colds arrive.

In Spitsbergen it was introduced to an unfavourable place on a harsh coast, far away from the middle arctic zone. Many authors have assumed Saussurea to be native in Spitsbergen but this is highly improbable. When first found in 1954, the collector (W. Solheim, Herb. O), noted on the sheet: "Flere planter satt i en rund ring som et bed. Plantene hadde formert seg og skuddene var riktig frodige." (Several plants were found in a circle, as planted in a flower bed. The plants had reproduced [meaning vegetatively] and were quite luxuriant). When observed by I.G. Alsos in 2008, this was still the case: all the plants grew in a ring-formed structure. We are quite sure that this plant has been introduced to Spitsbergen as an ornamental and has persisted for at least 60 years, probably much more.