Calcium, magnesium, potassium, sodium, and phosphorus concentrations were measured in the shoots of a Phragmites communis community and its natural substrates during the growth season of 1969. Shoot length and shoot moisture were determined as indicators of physiological age. In addition, organic decay was followed by determination of the soil organic matter content and cation exchange capacity. Of the ions studied, calcium apparently increased in the shoot tissue, and magnesium, potassium, and phosphorus apparently decreased in the shoot tissue during the course of the growing season. Some speculations regarding the direction of net nutrient on flow in this community are advanced.

Calcium, magnesium, potassium, sodium, iron, and phosphorus concentrations were measured in rhizomes, leaves, and floral stalks of a Typha glauca community during the growth season of 1968. Leaf—length and plant—organ moisture contents were also determined and used as indicators of physiological aging. Seasonal fluctuation was found in all ions examined in the soil and plant parts analyzed. The ions studied were grouped into three categories with reference to apparent seasonal fluctuations of ionic concentrations. Concentration changes of calcium and possibly magnesium in plant tissue were inversely related to apparent changes in substrate concentration. Changes in concentration of potassium and phosphorus in floral stalks and leaves were inversely related to apparent changes in ion concentration in the rhizome, although not related to changes in the substrates. Changes in concentration of sodium and iron in all plant parts sampled were directly related, but no relationship was detected between the apparent changes in concentration in plant tissue and those in the substrates.