Systematics, Distribution and Anatomy of the Two Indian Species of the Genus Elatine L.

The paper presents an illustrated description of Elatine ambigua Wight and E. triandra Schkuhr (E. americana Arn.) of the family Elatinaceae with data on their distribution, pollen and general anatomy. The present collection of the two species from Ramappa and Pakhal, Andhra Pradesh, represents a second area of their distribution apart from Madras State. Additional features on their anatomy have been recorded. On the basis of field observations and anatomical features the species are grouped under floating-leaved anchored hydrophytes. The achlorophyllous epidermis and ledged guard cells, which are not in tune with typical characters of hydrophytes are regarded as of vestigial nature. E. ambigua is represented by two forms, one mesic and the other aquatic, which are considered to be ecoadaptive forms or ecads rather than two different genetic races. The anatomical characters are found to be too simplified to help in establishing the taxonomic position of the family.