Perennial, but probably not very long-lived.
A mainly solitary herb with short creeping stems, only rarely branched. Most leaves basal. Flowering stems erect, up to 6–10 cm.
Leaves alternate. Basal leaves 2–4, 2–3 × 0.6–0.8 cm, narrowly lanceolate or elliptic, entire or crenate; stem leaves shorter and more narrow.
Flowers singly at top of stems.
Flowers radially symmetric, nodding at flowering but becoming erect in fruit stage. Calyx 1–2(3) cm long, fused, with 5 linear, appressed lobes, tube and lobes pubescent. Corolla protruding 0.5–1.5 cm from the calyx tube, fused, funnel shaped, dull blue, with 5 lobes cut to more than 1/3 of corolla length, remaining as withered on the fruit. Stamens 5, free. Gynoecium of 5 fused carpels, with 5 free styles.
Fruit a narrowly obovoid capsule with apical pores, 1.3–1.7(2.0) × 0.4–0.5 cm, with several seeds. The capsule remains erect in the fruit stage.
Sexual reproduction by seeds; very restricted local vegetative reproduction by short creeping stems. The plant flowers from mid July to mid August. Flowers potentially pollinated by insects but self pollination is probably common. We have no information on germination rate of seeds of the Svalbard populations; however, the plant must recruit regularly as populations of this relatively short-lived plant sustain in the same locations for a long time.
Local seed dispersal is facilitated by the stiff stems and the capsules with apical pores, resulting in ballistic dispersal during strong winds or when touched by animals (reindeer).
The two species of Campanula in Svalbard differ in numerous features. Campanula uniflora grows mostly solitary, has leaves lanceolate or elliptic (i.e., of mainly one shape), flowers small and narrowly funnel shaped, and capsule erect with pores apical on the capsule. Campanula rotundifolia is mat-forming, has leaves obcordate to linear (two different shapes, i.e., ‘heterophylly’), flowers large and broadly bell-shaped, and capsules pendulous with pores basal on the capsule. They can hardly be mistaken for each other or for any other Svalbard plants.
Growing in favorable sites with abundant insolation. Occurring most often among other forbs, graminoids, and dwarf shrubs on slopes and ledges with meadow or heath vegetation. The growth sites are usually well drained with mixed soils and circumneutral or basic soil reaction (pH). Tends to occupy moderately exposed locations with slight to moderate snow cover. Not much grazed by reindeer or geese.
Thermophilous. Found mainly in the middle arctic tundra zone and in the clearly and weakly continental sections. Restricted to the climatically favourable fjord areas in C and N Spitsbergen, with a single site southwest of Lidfjellet in the Hornsund area (Sørkapp Land, in the northern arctic tundra zone and the transitional section).
Campanula uniflora is mainly an American and Greenland species, reaching across the North Atlantic to Iceland, Scandinavia, and Svalbard (and across the Bering Strait to Chukotka), see Hultén & Fries (1986).
The western arctic range suggests that the connections of the Svalbard plants of Campanula uniflora is either to the south (Scandinavia) or west (Greenland), most probably the latter.
Hultén, E. & Fries, M. 1986. Atlas of North European vascular plants north of the Tropic of Cancer. I–III. – Cramer, Vaduz.