Meetings of the Royal Botanical Society of the Netherlands

A phytosociological study of the ”dry evergreen forest” or Marakkanam (South-East India) and the thickets near Maduranthakam and Ulundurpet, using the Zurich-Montpellier method of vegetation survey, has resulted in a delimitation of six plant communities with three subtypes. These are: 1. Basella alba community, a well developed thicket, corresponding to the scrub woodland stage of the Albizia amara – Acacia series (Legris 1963), with a dominance of Albizia amara in the tree layer. The community occurs on the more sheltered sides of monsoon gullies and in a more degraded form on flats. Most characteristic species are deciduous. 2. Gyrocarpus jacquinii-Cardiospermum halicacabum community, a parallel community of the Basella alba community on skeletal slopes of hillocks, characterized by rocky outcrops and charnockite boulders. 3. Clausena willdenovii community, being thicket remnants of the Basella alba type. 4. Pterospermum suberifolium-Garcinia spicata community on the sides of not so deep monsoon gullies, on sandy soils with a relatively high percentage of clay and loam. The characteristic species are evergreen. 4a Subtype with Syzygium cumini and Walsura trifoliata. occuring in monsoon streambeds and on their levees. 5. Erythroxylum monogynum-Chloroxylon swietenia community, occurring on flat eroded soils with large quantities of gravel. 6, Borreria articularis-Lepidagathis cristata community of open places and footpaths comprising two subtypes: (a) a subtype with Vernonia cinerea, a highly disturbed bushclump thicket; (b) a subtype with Dodonaea viscosa and Indigofera glabra. an open pioneer vegetation occurring along footpaths and in open sites in the thickets. These communites can be grouped in two main types, the Pterolobium hexapetalum-Melothria maderaspatana type, presenting community 1, 2 and 3, and the Manilkara hexandra-Canthium dicoccum type, including community 4 and 5. Both types possibly have the status of an alliance in syntaxonoraical classification. The former'type occurs in the drier habitats of the coastal and interior regions of the eastern half of Peninsular India, and is probably identical to the Pterolobium hexapetalum-Erythroxylum monogynum facies distinguished by Meher-Homji (1973) and to the scrub woodland stage of the Albizia amara – Acacia series distinguished by Legris (1963) and Gaussen et at. (1962). It is a deciduous thicket with many spiny straggler lianas. The latter type corresponds to the Manilkara hexandra, etc, facies distinguished by Meher-Homji (1973,1974b) and is limited to the coastal tracts of Coromandel and Circar. In Marakkanam it is a dense, mainly evergreen vegetation with a few spiny straggler lianas and a less patchy character than the Pterolobium hexapetalum-Melothria maderaspatana type. It occurs on fine, deep soils in a relatively moist habitat.