Lycopodium annotinum and light quality: Growth responses under canopies of twoVaccinium species

Lycopodium annotinum, a clonal pteridophyte, was grown under canopies formed by various combinations of deciduousVaccinium myrtillus and evergreenV. vitis-idaea. The canopies differed in red:far-red ratio, withV. myrtillus giving the lowest ratio. The current year's horizontal segments ofL. annotinum had the same specific weight in all treatments, but the lengths of the segments were significantly increased when grown under the canopy ofV. myrtillus compared withV. vitis-idaea. The number of vertical apices was also increased. Both these responses increased the amount of assimilating structures ofL. annotinum when growing under aV. myrtillus canopy. This might be beneficial for the evergreenL. annotinum, since it can then utilize spring and autumn periods when the deciduousV. myrtillus has no leaves.