This section is from the book "Harper's Guide To Wild Flowers", by Caroline A. Creevey. Also available from Amazon: Harper's Guide To Wild Flowers.
Family, Parsley. Flowers, small, urn-belled, pedicelled, white or greenish, from rootstocks creeping in the mud. The leaves are tiny imitations of lily-pads. After flowering, the top of the water where it grows is covered with the specks of white blossoms. Leaves orbicular, crenate, small, with the long petiole fastened to the middle underneath. June and July. (See illustration, p. 99.)
Water Pennywort (Hydrocotyle umbellata)
H. verticittata. - This species has few flowers in umbels, in interrupted spikes. Leaves like the last. June to September.
Massachusetts to Florida and westward.
H. americana. - Flowers, very small. Leaves, kidney-shaped. Sometimes called water ivy. It has small, thread - like stems which creep over wet moss and cling to soil mud. The pretty, shiny, roundish or kidney - shaped leaves, crcnalely lobed, are very common in marshy places. The tiny flowers are clustered in the axils. They are nearly stemless. Summer.
Water pennywort (Hydrocotyle americana)
The outward resemblance to other genera of the Parsley Family is remote. All these species are sometimes aquatics. The leaves have scale-like stipules. (See illustration, p. 101.)