The genus Nymphoides Séguier (Menyanthaceae) in India

A New Genus and New Combinations in Australian Villarsia (Menyanthaceae)

“…Some (e.g. N. indica ) have rather broad distributions, but most are restricted to a single continent or even to a local geographic region ( Aston 1973( Aston , 1982Raynal 1974b ;Sivarajan and Joseph 1993 ;Li et al 2002 ). Several regional taxonomic treatments exist for Nymphoides , but there has been no recent comprehensive treatment of the genus worldwide.…”

“…With two exceptions ( N. cambodiana and N. exiliflora ), Nymphoides species produce distinctive floating leaves that subtend umbellate flower clusters or lax racemes ( Aston 1973 ;Sivarajan and Joseph 1993 ; ). Flowers are borne above water, but the capsular fruits develop underwater ( Aston 1973 ;Raynal 1974a ).…”

“…Seeds differ among species in their shape (globose or elliptical, some compressed laterally), size (from 0.4 mm to over 5 mm), surface ornamentation (smooth or tuberculate, some carunculate), and number (from one or two to over 100 per fruit). Although floral and seed characters vary among species, other features like inflorescence architecture and fruit structure are more consistent across taxa ( Raynal 1974a ;Aston 1982Aston , 2003Chuang and Ornduff 1992 ;Sivarajan and Joseph 1993 ).…”

“…Floral axes are either expanded (having internodes that elongate between pairs of flowers) or condensed (with each cluster of several flowers supported by a single floating leaf) ( Aston 1982 ;Sivarajan and Joseph 1993 ). The temperate Eurasian species N. peltata produces a unique third inflorescence type, in which two leaves support each of several successive flower clusters on an axis with elongated internodes ( Raynal 1974a ).…”

“…Heterostyly is the ancestral condition in Menyanthaceae, with the syndrome lost independently in several nonheterostylous lineages ). In addition, four Nymphoides species (N. aquatica , N. cordata , N. krishnakesara , N. macrosperma ) are dioecious, having both flowers and individuals that are unisexual ( Ornduff 1966 ;Sivarajan and Joseph 1993 ). Still another condition characterizes the gynodioecious N. cristata , a species in which individuals produce either pistillate (female) or hermaphroditic flowers ( Vasudevan Nair 1973 ).…”