THE CHEMICAL ECOLOGY OF THREE SPECIES OF MYRIOPHYLLUM (ANGIOSPERMAE, HALORAGACEAE)l*”

• Main Author: G. E. Hutchinson
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 1970
• Subjects: Northern Sweden
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.483.5901; http://www.aslo.org/lo/toc/vol_15/issue_1/0001.pdf

Analysis of the data published by Lohammar indicates that Myriophykm alternifbrum occurs in moderately acid, neutral, or slightly alkaline waters. Both Myriophyllum qkatum and Myriophyllum verticillatum extend into waters having higher calcium contents than appear to be tolerated by M. alterniflorum. MyrzbphyZZum verticillatum tends to occur in waters having a lower pH than many inhabited by M. spicatum. The difference is highly significant and may be correlated with M. spicatum being able, and M. verticilkztum not being able, to use the bicarbonate ion as a source of carbon in photosynthesis. In northern Sweden, in a region the lakes of which did not contain M. verticillatum, the soft-water part of its niche may be occupied by M. spicutum. Examination of various other genera containing two or more species fails to show any other clear-cut cases of pH limita-tion in the alkaline waters studied by Lohammar; usually the more calciphil species seem to require and thrive at high calcium concentrations. soft water low pH may be limiting. It is however possible that in very As Arber ( 1920, p. 286) wrote 50 years ago, “The majority of hydrophytes. show definite preferences and aversions in the matter of the soil underlying the water, in which they grow, and of the resulting differences in the nature of the solution in which they are immersed. ” By far the most important of the chemical distinctions in-volved in these preferences and aversions is that between hard water draining from more or less calcareous sedimentary rocks and soft water draining for the most part from igneous rocks. Such a seemingly sim-ple dichotomy is however highly complex. In the case of rooted plants we may have l In memory of Agnes Arber on the 50th anni-versary of the publication of Water plants.