Forest Flora of Thenmala (and its Environs)

Contents: Preface. I. Introduction: 1. Significance of the study and brief review of earlier work. 2. Geographical location and physical features. 3. Physical features of Thenmala. 4. Geology, soil and climate. II. Vegetation: 1. Tropical wet evergreen forests: a. Altitudinal distribution of wet evergreen forests. b. Horizontal distribution of wet evergreen forests. c. Biotic interference in relation to natural regeneration. 2. Tropical fresh water swamps (Myristica swamps). 3. Tropical semi evergreen forests. 4. Tropical moist deciduous forests. 5. Aquatic and marshy vegetation. 6. Grasslands. 7. Cultivated plants and weeds of fields. III. Discussion: 1. Statistical synopsis of the flora of Thenmala. 2. Biological spectrum of Thenmala. 3. Vegetation in relation to rainfall and duration of drought. 4. Floristic pattern. 5. New distributional records. 6. Medical, horticultural and other economically important plants. 7. Miscellaneous botanical observations. Abbreviations used. Key to the families. Alphabetical list of families dealt within the flora. Systematic treatment of the families. Reference. Index to botanical names. Index to Malayalam.

From the introduction: "The Deccan plateau of South India is fringed on the western side by a narrow mountain range extending in the north-south direction and facing the Arabian sea. This undulating range of hills of varying altitudes called the western ghats gently slopes to the sea, forming a narrow coastal belt criss-crossed by many fast flowing rivers. By virtue of its geographical location, topography and rainfall from both the north-east and south-west monsoons, the western ghats shelter a belt of wet tropical evergreen forests stretching from Maharashtra to Kerala.

"References to the flora of western ghat region are found even in the earliest floristic accounts of the Indian flora. As far back as 1678-1703, Van Rheede published an account of the plants of some regions of the west coast of south India, including some parts of the western ghats, in his classical work "Hortus Indicus Malabaricus". Later, an attempt for a comprehensive study of Indian flora was undertaken by William Roxburgh. Based on his extensive and pioneering studies, he completed an account of the flora of the Indian subcontinent; the work was published posthumously in two volumes under the title, "Flora Indica" during 1820-1824. Subsequently, a team of botanists under the leadership of Sir J.D. Hooker undertook a very comprehensive study of the Indian flora and this work of Flora of British Indica (1872-1897) remains till today as the only authentic reference to the floristic composition of the country as a whole. The flora of the western ghats figure prominently in this monumental work.

"The publication of Flora of British India by Hooker stimulated more detailed field work and compilation of floristic accounts of various regions of the country. The important provincial floras that followed are Punjab Plants by J.L. Stewart (1869), Bengal Plants by D. Prain (1902), Flora of Bombay Presidency by T. Cooke (1903-1908), Flora of Upper Gangetic Plains by J.F. Duthie (1903-1929), Flora of Madras Presidency by J.S. Gamble and C.E.C. Fischer (1915-1936), Flora of Bihar and Orissa by R.H. Haines (1922-1925) and Flora of Assam by U. Kanjilal and A. Das (1934-1940) - all these are still valued for their rich and scholarly contents. While all these works have served a generally familiarise us with the flora of the country, any detailed and intimate knowledge of the floristic composition of any given region of the country can only be obtained by a devoted and sustained collection and critical study of smaller areas.

"Flora Simlensis by H. Collett (1902). The Flowering Plants of Madras City and its Immediate Neighbourhood by P.V. Mayuranathan (1929), The Flora of Khandala on the Western Ghats of India by H. Santapau (1963), Flora of Delhi, by J.K. Maheswari (1963) and Flora of Hassan District, Karnataka, India by Cecil J. Saldanha and Dan H. Nicholson (1976) are examples of ardent studies on the flora of small areas in the country, which need emulation. As regards the western ghat area, such intensive studies are few; the Flora of Hassan District by Saldanha and Nicholson is perhaps the only one worth mentioning, dealing with any region of the western ghats, even though mention must be made of few others like the Forest Flora of the Bombay Presidency and Sind by W.A. Talbot (1909-1911) and Forest Trees of Mysore and Coorg by J. Cameron (1894). In view of the fact that the western ghat forests are fast disappearing, it is imperative that detailed studies on similar lines are undertaken, of other regions of the area, especially those areas where near virgin forests are still left. The present work was undertaken with this objective and deals with the Flora of Thenmala, an area between Shenkottah and Quilon on the western slopes of western ghats of Kerala state. This area is unique in many respects by virtue of its climate, proximity to equator, topography and rainfall, a natural condition to foster a very rich flora. No intensive work of the flora of this area has been done, inspite of a variety of vegetational types available in a short stretch of forest area."

[K.N. Subramanian is Director, Institute of Forest Genetics and Tree Breeding.]