Effect of cold stratification on germination of 9 boreal sedges

Many sedge species (Carex L. [Cyperaceae]) are found in varied vegetation communities that make up the boreal forest in northwest Alberta, Canada. Sedges make up a large part of wetland vegetation and, to a lesser extent, upland communities. Until recently, few have been considered for use in reclamation or revegetation of sites disturbed by oil and gas extraction, due in part to the lack of information regarding their germination requirements. Germination of 5 upland species: Dewey sedge (Carex deweyana Schwein.), meadow sedge (C. praticola Rydb.), smallwing sedge (C. microptera Mack.), Raymond’s sedge (C. raymondii Calder), and dryspike (C. siccata Dewey) and 4 wetland species: sparseflower sedge (C. tenuiflora Wahlenb.), three-seeded sedge (C. trisperma Dewey), northern bog sedge (C. gynocrates Wormsk. ex Drejer), and tall bog sedge (C. paupercula) were evaluated following 3 cold stratifications treatments (2, 4, and 9 wk) and that of an unstratified control (0 wk). Germination (% and days to maximum germination) and synchronization index of the 9 Carex species differed following a 0, 2, 4, or 9 wk cold stratification at 4 °C (39.2 °F). For 6 sedges, very good germination (more than 75%) was achieved, whereas acceptable germination (69%) was attained for C. deweyana, and poor germination (< 20%) for C. gynocrates and C. trisperma. Further investigation will be required to understand germination requirements for the latter two.