Flowering strategies of the high‐arctic and high‐alpine snow bed grass species Phippsia algida

Flowering requirements of the high‐arctic and high‐alpine snow bed grass species Phippsia algida (Sol.) R. Br. have been studied in controlled environments. Seedlings flowered rapidly in continuous long days (LD) at temperatures ranging from 9 to 21°C. They also initiated inflorescence primordia at the same temperatures in continuous short days (SD), whereas LD were required for heading and anthesis. The plant thus has the characteristics of a regular long day plant, although the daylength requirement is associated with floral development only. The critical daylength for the LD response was about 17 h at 21°C and 19 h at 9°C. A single LD cycle was enough to trigger inflorescence development, while 5 cycles were required for the full response. Anthesis was reached within a week of LD treatment at 21°C in SD grown plants with preformed inflorescence primordia. The advantages of these versatile flowering responses are discussed in relation to the extreme climatic regime of late snow bed sites.