Annual or perennial herbs. Stipules 0. Leaves alternate, opposite or whorled. Flowers actinomorphic, rarely zygomorphic, bisexual. Calyx gamosepalous, (4-)5(-9)-partite. Corolla gamopetalous, rotate to campanulate with a 4-9-lobed limb. Stamens equalling corolla lobes, sometimes alternating with staminodes. Ovary semi-inferior (Samolus) or superior (other genera) or 1-locular; ovules 2-3 or more, usually many. Fruit a capsule.
"Farther south, in Europe, the severities of the Arctic are only equalled on high mountains…Close to the edge of permanent snow, this growing period may be very brief indeed. The snow may have taken so long to melt that the sun has already passed its summer peak before the rocky cliffs are exposed and there is moisture to be extracted from the gritty ground…This is where the alpine snowbell grows. Because growing time is so short, it has to be prepared to take immediate advantage of the first thaw. Accordingly, it has, ready and waiting, flower buds that were developed at the end of the previous short summer. Throughout the winter they have remained dormant, protected by the blanket of snow above. In spring, even before the snow melts, the glimmer of slightly brighter light, filtering through the white blanket above, triggers the plant into activity. The dark surface of the flower-buds absorbs the heat of such sunlight that manages to filter down to them and this speeds the melting of the snow. As moisture from the sun-warmed surface of the snow begins to trickle into the ground, the little snowbells suddenly appear in the sunshine, each sitting in the centre of its own dimple in the snow-field." (Attenborough 1995:251-252) Learn more about this functional adaptation.
Attenborough, D. 1995. The Private Life of Plants: A Natural History of Plant Behavior. London: BBC Books. 320 p.
Barcode of Life Data Systems (BOLD) Stats Specimen Records:2329 Specimens with Sequences:3560 Specimens with Barcodes:1943 Species:608 Species With Barcodes:596 Public Records:1735 Public Species:531 Public BINs:0
Källersjö, M., G. Bergqvist & A. A. Anderberg. 2000. Generic realignment in primuloid families of the Ericales s. l.: a phylogenetic analysis based on DNA sequences from three chloroplast genes and morphology. Amer. J. Bot. 87: 1325–1341.