Environmental control of flowering and morphology in the high‐arctic Cerastium regelii, and the taxonomic status of C. jenisejense

• Published in: Nordic Journal of Botany
• Main Authors: Heide, O. M., Pedersen, K., Dahl, E.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1990
• Subjects: Plant Science; Ecology, Evolution, Behavior and Systematics; Arctic
• Online Access: http://dx.doi.org/10.1111/j.1756-1051.1990.tb01761.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1756-1051.1990.tb01761.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1756-1051.1990.tb01761.x

Cerastium regelii has a distribution confined largely to regions north of 70° N but has retained a strong short‐day (SD) response for primary flower induction despite the fact that it will hardly ever experience SD in a non‐frozen condition in its natural environment. However, like many other high‐latitude short‐long‐day plants it has also an alterntive long day (LD) pathway for floral initiation at low temperatures (<15°C). Floral primordia which are fully differentiated during SD have an absolute requirement for LD for flower development. The critical photoperiod for this LD response is about 16 h at 18°C and more than 20 h at 9°C. Plant morphology, including key characters for identification of the species, is greatly modified by environment and stage of plant development. At higher temperatures and LD C. regelii develops a striking resemblance to the sub‐arctic C. jenisejense . Based on examination of authentic herbarium material it is concluded that the latter is merely a high‐temperature morphotype of C. regelii .