Life span

Perennial, probably short-lived.

Growth form

Solitary herb with an often abundantly branched, mainly vertical caudex. Caudex branches ending in leaf rosettes at ground level. Rosette groups up to 10 cm in diameter but usually much smaller. Flowering stems dark green or purple, 1–several from rosettes, 0.5–3(4) cm, usually with 1 small stem leaf subtending a not developing flower bud or a single flower well below the main inflorescence. The entire plant is glabrous.

Leaf

Leaves alternate. Basal leaves usually 3 per rosette, 5–15 mm long with a slightly winged petiole 2.5–8 mm and a blade 2.5–7 × 1–3 mm, oblong to ovate, obtuse to rounded, entire, dark green.

Inflorescence

Inflorescence a short raceme, 0.7–1.0 × 0.7–1.0 cm in flowering stage, with 1–4(5) ebracteate flowers, elongating moderately in fruiting stage.

Flower

Flowers on pedicels ca. 2 mm, radially symmetric, 5–6 mm in diameter, with 4 free sepals and petals. Sepals ca. 2 × 0.8–1.0 mm, ovate, obtuse to rounded, purple with narrow, white hyaline margins. Petals 2.8–3.2 × 1.0–1.4 mm, about twice as long as sepals, non-overlapping, spathulate, with narrow claw, apex rounded or slightly notched, white. Stamens 6; filaments 1.6–2.0 mm, 2 of the 6 filaments flattened; anthers ca. 0.3 mm. Gynoecium of 2 carpels with 2 rooms separated by a secondary, hyaline wall.

Fruit

Fruit a siliqua on pedicels 2–5 mm, narrow, 10–20 × 1–1.5 mm, not flattened, purple or dark green, with 2 rooms and 1 row of seeds in each room. Seeds 5–8 per room, 1.0–1.2 mm, brown.

Reproduction

Sexual reproduction by seeds; no vegetative reproduction. Adapted to insect pollination but we assume that self pollination prevails. Seed production in Svalbard abundant and little damaged by weather.

Seed dispersal passive; no adaptation to any special ways of dispersal except that the valves open ‘explosively’ and spread the seeds a few cm.

Comparison

Cardamine bellidifolia can be mistaken for Braya, Cochlearia, Eutrema, and white-flowered species of Draba. It differs from Braya and all white-flowered Draba in being glabrous, from Draba in addition by the narrowly linear fruits. It differs from Cochlearia also in the very narrow fruits and the shape of leaves (short and broad in Cochlearia). The most similar may be Eutrema edwardsii. In Cochlearia nearly all leaves are basal and the fruits are linear and congested in the short infrutescence; in Eutrema most leaves are cauline and the fruits are tapering towards the apex and sit in an elongated infrutescence.

Habitat

Mainly on open and moist to wet mineral soils but also in moss tundra. Cardamine bellidifolia is adapted to short growing season and therefore relatively common in snowbeds. Other common site types are river banks and fresh moraines. The species is probably moderately acidophilic and less common in areas with alkaline soils.

Distribution

Present in all zones and sections. Occurring occasionally or as relatively common in local areas on all the major islands of Svalbard but never in large amounts. Occurrence of C. bellidifolia is known to increase with altitude up to ca. 400 m a.s.l., with altitude limit at 845 m on Gattyfjellet.

This is a widely distributed arctic-alpine circumpolar plant known from all arctic regions and reaching far south in mountains in the boreal and temperate zones.

Comments

Even if very widely distributed in the entire Arctic and in many more southern mountains, C. bellidifolia has its only close relatives in the mountains of C and S Europe (C. alpina Willd. and C. resedifolia L.). These three species constitute a very distinct clade in an ITS Cardamine phylogeny (Carlsen et al. 2009). In Svalbard, it is an uncommonly uniform species.

Literature

Carlsen, T., Bleeker, W., Hurka, H., Elven, R. & Brochmann, C. 2009. Biogeography and phylogeny of Cardamine (Brassicaceae). – Annals of the Missouri Botanical Garden 96: 215–236.