R LUOND’s research while affiliated with University of Zurich and other places

A taxonomic revision of the genus Nechamandra (Hydrocharitaceae) is presented with a full description, a diagnosis, typifications, synonyms, distribution maps and illustrations also including information on ecology, floral biology, anatomy, embryology, chromosome numbers, variation and taxonomic affinities. Nechamandra is considered to be monotypic. The single species, N. alternifolia (Roxb. ex Wight) Thwaites, is considered to be native in the Indian sub-continent and introduced in Vietnam and the Sudan. The chromosome number is disputed. The taxonomic affinities of Nechamandra are with Vallisneria rather than Lagarosiphon and it is therefore transferred from the Anachariteae Ritgen. to the Vallisnerieae Endl.

Blyxa octandra (Roxb.) Planchon ex Thwaites is a dioecious aquatic plant. In the male flower the pollen is deposited on the adaxial surfaces of the petals whilst it is in bud. The petals elongate and spread, thus presenting the pollen to pollinating insects. The female flower only superficially resembles the male; the petals are much smaller and the stigmas are spreading and petal-like. The attractive function of the petals in the male is, therefore, transferred to the stigmas in the female. Between 09.30 and 10.00 h the petals in the male and the stigmas in the female exude water-like droplets. The flowers are visited by various Diptera and Odonata who transfer pollen on their feet. By midday the flowers dry out and wither.