INTRODUCTION The tropical rain forest is the most complex eco­ system on the earth. It is the richest of all ecological communities in terms of number of species of all types of groups within the plant Icingdom viz; higher angiospermic plants, epiphytes, parasites, bryophytes, lichens, etc. Many closely related species are found in the same general area although each species is represented by only a small number of individuals (Richards, P.W., 1973). Since the past, the tropical forest has been an important source of knov/ledge about nature and the human environment. These tropical rain forests still remain the largest scientifically unexplored regions of the world. Even among those species that have been named and described from these regions; we know virtually very little or almost nothing about their biological characteristics. In addition to this, these forests are retreating very fast. In 1975, the following estimates of cumulative destruction of tropical forests were made by the FAO and UNESCO : 2 Original area of Tropical : 16 million km . Rain Forest (World) 2 Area in 1975 : 9.36 million km . (Reduction of 41.5%) - 2 - The rate of destruction of these forests is greater than that of the temperate forests. If this destruction is continued with the same rate, many interesting taxa may disappear before there is even a record of theirexistence. India being situated in the tropics, has a typical tropical .flora. The tropical rain forests exist at Andaman- Nikobar Islands, North-East India and Western Ghats of South India (Map 1). All these forests are already explored and are still being explored for their higher angiospermic flora and mycoflora. Lichen flora of these forests of the Western Ghats was not studied till 1973. Since 1973, Department of Mycology of the Maharashtra Association for the Cultivation of Science, Pune, has started exploring the Western Ghats of India for lichenized fungi. Based on the results of the work done under the National Science Foundation, U.S.A., funded research project "Lichens of Western India" accounts of the lichen families Usneaceae and Physciacsae (Rairkar, 1976, unpublished), Parmeliaceae and foliicolous lichens (Prabhu, 1976, unpublished), Graphi- daceae and Thelotremataceae (Kulkarni 1977, unpublished), Pyrenocarpous lichens (Makhija 1978, unpublished) were prepared. Nagarkar (1975, unpublished) worked on lichen flora of Mahabaleshwar. - 3 - An extensive and rapid survey in the Western Ghats showed that several parts in the North Canara (Devimane Ghat/ Yellapur, Siddhapur forest) and South Canara (Mudi- gere, Agumbe, Karakkal, Coorg) are richer in relics of old primary broad leaved woodlands that have been relatively ]ert.‘ ■ modified by forestry and agricultural techniques than in any other parts of India. These forests because of humid microclimate and continued presence of well developed evergreen trees still retain finer assemblages of epiphytic and lignicolouH lichens often v/ith excellent representation of old world tropical species and even endemic elements (Patwardhan, 198i). Tropical rain forests exist on the hill tops and ravines in the Western Ghats. This chain of hill ranges runs through the seven districts of the state. Most of the lichen collections were made in these districts. Remaining 12 districts (namely Bijapur, Gulbarga, Bidar, Raichur, Bellary, Dharwar, Chitradurg, Tumkur, Kolar, Bangalore, Mandya and Mysore) have fertile agricultural land and moist deciduous to dry deciduous forests. Hence lichens were not collected in these districts. I have had an opportunity to work under the research project "The lichens of tropical rain forests of Karnataka State" sponsored by Council of Scientific and Industrial - 4 - Research, India, and operated at the Department of Mycology, M.A.C.S.Research Institute, Pune from 1980 to 1983. The present thesis is based on the results of the floristic v/ork done under the project. The primary objectives of this project were to 1) make a floristic survey of lichens of the existing, endangered, evergreen rain forests in the Karnataka State and 2) to record lichen specimens before they are lost. GEOGRAPHY OF KARNATAKA STATE: Karnataka State shows a great variation in the climate and geography. It lies between 11° 5' N (B.R.Hills), and IS^ 00' N (Nandi Hills) latitudes and 74° 2' E (Belgaum) and 80° 35' E (Nandi Hills) longitudes. The altitudes vary from 250 m (Hubli) to 2075 m (Kudremukha). The annual average rainfall in the state ranges from 750 cm 'In the Western Ghats to about 37.5 cm in the Eastern and north eastern parts of the state. The average annual rainfall in the state is about 118 cm. The zone of heavy rainfall (150 cms.and over) extends from Coorg district to North Canara districts over a belt of 48 - 80 kms along the Western Ghats. CLIMATE; Karnataka state has tropical monsoon climate. The year can be broadly divided into three seasons viz., the cold - 5 - season from December to February which is generally free from rains; the summer season from March to May, v/ith rcare. thunder showers especially in the latter and hotter part, and the monsoon season from June to November of which South-west monsoon extends from June to September, account­ ing for the bulk of the total rainfall and the north-east post and retreating monsoon period from October to November. The climate is mild in the plateau region. The-relative humidity in the Western Ghat area is comparatively much higher than in the table land. SOILS: The soils of the state are divided into 5 main groups (Roychaudhary ^ 19 63) . 1) Coastal alluvium; It is limited to the narrow flat belt adjoining the sea. These soils are sandy v;ith very low clay or organic matter content. 2) Laterite soils: Mainly found in the area to the east of coastal alluvium. These soils exhibit a loamy or clayey surface with a lot of pellet concretions of varying thickness followed by laterite horizons. These soils are acidic and poor in plant nutrients. 3) Red soils: Mainly found in the southern part. These soils may be rich, gravelly, pale brown or red sandy - 6 - loam type, with their colour varying from place to place depending on presence of hydrated oxides of iron. 4) Mixed red, yellow and grey soils; These are generally sedentary soils. The texture of the surface soils varies from stony to sandy in the pale yellow to light red soils; .from loamy to clayey in the light red to deep red; and grey groups. Their pH varies from 6.5 to 7.5. They are poor in nutrients. 5) Black soils: Mainly found in Bijapur, Gulbarga, Bidar, Belgaum, Dharwar and Raichur districts. These have high clay content and v/ater holding capacity. Their pH ranges from 7.5 to y.5. These are very fertile being well supplied with plant nutrients. VEGETATION; The vegetation is diverse ranging from the tropical wet evergreen forests to scrub jungles. The wet evergreen forests are seen at altitude ranging from 600 - 1000 m on the windward side of the south-western ghats. These are the forests where lichens grow luxuriantly. The altitudinal distributions of the trees varies remarkably from the ghat- crest region to the interior even within a range of 5 to 8 km. The floristic composition reveals some common elements with the Indo-Malaya rain forests but are markedly different from the rain forests of Eastern India. As one passes from North Canara southwards; the constituents and density of the evergreen or semi-evergreen species vary with increase in rainfall. Though the evergreen forests of Shimoga, Chikmanglur, Hassan and Coorg show more or less similar components yet the floristic composition is markedly dissi­ milar to that in Kerala. At altitudes of 1200 - 1800 m or more, the hill tops exposed to the high velocity of the winds during the south west monsoon have stunted trees and in the sheltered valleys occur shola type vegetation. With decreasing altitude the vegetation gradually changes into evergreen wet-deciduous to dry-deciduous to scrub forests. The vegetation is generally divided into three parallel north-south zones or belts on the frequency of rain­ fall as follows- I. The evergreen belt: This stretches along the Western Ghats and situated in the region of heavy rainfall with a mean of 250 cmsor more per annum. This can be sub­ divided into two - 1) The moist evergreen belt -a very narrow belt along the Eastern Ghats and covering the mountainous country with deep ravines and narrov/ valleys. Its main - 8 - components are Dipterocarpus indlcus, Calophyllum apetalum, C. elatum, Hopea wiqhtiana, H. parviflora/ Holiqarna arnottlana. Plea dioica, Lophopeltalum wiqhtianum, Polyalthia Coffeoides, Persea macrantha, - Artocarpus hirsutum etc. 2) Mixed belt of evergreen and deciduous forest - The rain­ fall varies from 150 - 2 50 cms. The main deciduous trees are Terminalla panlculata, Dlospyrous sp., Laqerstromla mlcro- carpa, Elaeocarpus serratus, Mailotus phlllppensls, Ixora arborea etc. II. The deciduous forest belt: The rainfall In this area Is 75 - 100 cms. The chief species seen is Tectona qrandls while the other deciduous components are Grev/la fillifolla, Laqerstromla microcarpa, Kydla calycina, Dalberqia latitolla. Terminall a crenulata, T. panlculata, T. alata. Bombax ceiba, etc. III. Dry deciduous fuel tract and scrubs: It has a rainfall as low as 35 - 75 cms. This has xerophytlc plants along with some bamboos, in addition to the deciduous species. Its main components are Tectona qrandls, Anoqeissus latlfolia, Sterculia u r e n s , Acacia chundra, Dalberqia latlfolia, Dio- spyros tomentosa, Hardwlckia blnata, Haldlna cardifolla, Alblzla amara. Cassia fistula, Santalum album, and Gmelina arborea etc. Still poorer lands support scrub forests only, - 9 - v;hich may be sometimes composed of only Euphorbia antic/uorum, E. tjrucalli, Dodonaea viscosa. Cassia auriculata, etc. These divisions and subdivisions gradually merge into each other in the above order (Sharma B.D.