Plant of the Month is Caltha - one is the Caltha palustris Stagnalis the big grower of the family with 8" leaves and flower stems that drop down to the water surface to root on as new plants. This will grow in deeper water than the British Native Caltha palustris which is also in flower now from a shallower shelf in a shorter and more contained clump but still with a bright yellow flower to greet the new season.
There is also the Caltha palustris var. alba a white variety which has been flowering in March - ahead of the yellows. This does not like as much water over its crown and is happiest in shallow water or in waterlogged soil on the edge of the pond.