The Aponogetonaceae family

The family of Aponogetonaceae, until now, Sri Lanka had four species: · The two endemics of

with a wider distribution in the western, north–eastern and north central parts of the country and recorded only from Puttalam and Hambantota districts and a few localities along the eastern coast.

· The endemic distributed widely in the lowland wet zone while the other endemic

with a restricted distribution in a few localities in Nuwara Eliya and Horton Plains in the central hills.

The research team has ascertained the following about the new species: The flowering of occurs throughout the year, with the intensity increasing just after the rainy season.

is restricted to less shaded, slow-flowing shallow streams in the Rakwana hills in the Ratnapura district.

The new species closely resembles but differs with the combination of these morphological characters: · The plumule (shoot or stem) of

is attached to the section just below the middle of the embryo, while

has a plumule attached to the bottom of the embryo.

· After maturity, the inflores- cence (the complete flower-head including stems, stalks, bracts and flowers) of shows a whorled (twisted) flower arrangement around the inflorescence, while shows a spiral flower arrangement. · The fruits of have a slightly furrowed surface with a short curved terminal beak.

· has a non-branching cylindrical rhizome (underground root stem) while

has a branching cylindrical rhizome.

· The colour of the immature leaves of ranges from purple to maroon while it is light green in