Abstract
Stem cuttings, 30 cm long, of Myriophyllum exalbescens Fern. and M. spicatum L. were planted in three substrates: loam, sand, and peat. Growth responses of these species were compared in three independent experiments each of a duration of 50 days. In some cases M. spicatum grew more vigorously, but the previous growth conditions for the plant material at the start of the experiment influenced the total amount of growth. In all experiments the percentage of ash in M. exalbescens was greater than in plants of M. spicatum grown in the same environment. The two species remained distinct from one another in characteristics of leaf length, number of leaf divisions, and length of internodes near the apex of the main stem. Within each species a marked relationship between morphology and substrate was observed. On the nutrient-poor substrate, sand, leaves of M. spicatum converged in appearance towards leaves of M. exalbescens grown on the nutrient-rich substrate, loam.
Publisher
Canadian Science Publishing