STUDIES IN THE GERMINATION AND ESTABLISHMENT OF JUNCUS SQUARROSUS

Abstract

SummaryObservations and experiments on the germination and establishment of Juncus squarrosus are described. Germination is confined to seeds lying on the ground surface and normally occurs in the spring. It was shown experimentally that germination can occur on a variety of media, including a calcareous soil, but that the germination percentages were reduced on dry soils. Complete germination of viable seeds occurred in 13 days in suitable conditions (frequent watering, 12 hours of light per day, and a room temperature of 23° C), but the rate was lower when less light and lower temperatures were given. At 14° C, germination did not occur in darkness and it would appear that light is either necessary for germination at this temperature, or raises the temperature of the medium surface sufficiently for germination to occur. Upland winter conditions had no effect on the viability of the seeds.Development of both root and shoot is very slow and evidence is presented that lack of competitive ability is the reason for the infrequency of successful establishment of seedlings. Colonization on blanket peat was found to be encouraged by lime and fertilizer treatments, but very few seedlings became established unless competition from Calluna, Eriophorum or a sown grass was reduced.