DIVERSITY, REASSESSMENT AND PHYTOGEOGRAPHICAL SIGNIFICANCE OF ANGIOSPERMIC GENERA RESTRICTED IN INDIA AND ITS ADJOINING AREAS

Plant Taxonomy: Advances and Relevance, Pages 145-162 Eds. A.K.Pandey, Jun Wen & J.V.V.Dogra - 2005 © CBS Publishers & Distributors, New Delhi Diversity, Reassessment and Phytogeographical Significance of Angiospermic Genera Restricted in India and its Adjoining Areas S. MITRA AND SOBHAN KR. MUKHERJEE Department of Botany, University of Kalyani Nadia-741235, West Bengal, India (e-mail:sobhankr@yahoo.com) ABSTRACT The Indian flora is actually an admixture of flora of its surrounding areas, as well as the representatives of the countries like Africa, America and Australia, besides its own 33.5% of the endemic floristic elements. The present paper deals with 268 angiospermic genera and 782 species belonging to 80 families, which are restricted in their distribution in India and its adjoining areas. From the list of these restricted genera of Angiosperms, it may be indicated that the phylogenetically advanced families like Orchidaceae, Asteraceae, Lamiaceae, Poaceae etc. are the most diversified on the basis of their number of genera and species, whereas the primitive families like Annonaceae, Magnoliaceae, Ranunculaceae, Circaeasteraceae etc. show poor diversification in their number of genera and species. It is also interesting to note that the advanced diversified families are restricted in the areas, which are geologically young like the Himalayan region and the primitive poorly diversified families are restricted in the geologically older region like the Deccan Peninsula and the Indomalayan region. On the basis of the distribution of these restricted genera, the phytogeogfaphic significance of the Indian region has been indicated. Keywords: India, Angiosperms, diversity, phytogeography INTRODUCTION India with her mainland area of about 3.26 million sq km extends from south to north between 8°4' to 31%' N latitude and from west to east between 68°7' to 97°25'E longitude, situated in the southern peninsula of Asian continent with its triangular peninsula extending 146' Plant Taxonomy : Advances and Relevance into the Indian ocean. Besides its mainland area, the Lakshadweep in the Arabian sea and the Andaman and Nicobar group of islands in the Bay of Bengal are also within the territory of India which estimated the area of Indian land is nearly 3.29 million sq km in totality. The latitudinal variation from 8° to 37° N latitude divided Indian subcontinent into 4 distinct climatological zones, viz., equatorial, tropical, subtropical and warm temperate. Besides this, the latitudinal variation from the sea level to the world's largest and the highest mountain ranges - the great Himalayas bounds the country at its northern boundary extending for a distance of about 2500 km, from east to west; the long coast line of about 6700 km; extremely arid zone at Thar dessert of Rajasthan at its western side; the upland in the Deccan plateau, surrounded by the hill ranges of Bindhya, Satpura system in the north, the Western Ghat along the western coast line and the Eastern Ghat at its eastern coast line converging with the Nilgiri mountains in the south and the extensive rivarine systems which helps to develop one of the world's largest river basin - the great plains of Ganga-Bramhaputra basins, forms the salient physiographic features of the Indian subcontinent. On the basis of this physiograpic variations, the Indian subcontinent is divided into 11 distinct zones (Balakrishnan, 1996). This varied physiographic as well as climatic condition influence the development of a diversified floristic composition, representing by more than 17500 taxa of angiosperm plants (Karthikeyan, 2000). Some 300 million years ago the configuration of the Indian landmarks was not identical with the present days. The then India occupied high latitude and laid quite close to the southern pole. According to the continental drift theory, the peninsular India was formed from the part of the Gondowana land and it got detached from it about 75 million years ngo and started drifting towards northern direction. This Indian plates moved about 5900 km continuously before it crushed against Laurasia in the northern tropical latitude during the late cretaceous. This continuos movement of Indian plate towards the north, resulted in crumpling of sediments and progressive shallowing and narrowing the Tethys. As a consequence of this, east west basins with intervening high lands were formed between 37-53 million years ago and currently in 15 million years ago by the last major phase of the northern movement of the Indian plates from the upliftment of the Himalayas by crushing against the southern part of Laurasia. The breaking away of Indian plates from the massive Gondowana land, movement towards north, shrinking of Tethys, formation of fordeep or basin, extending from east to west, complete obliteration of the Tethys, upliftment of Himalayas, formation of land bridges and land connections, migration starts and almost disappearance of warm humid tropical vegetation, continuous increase in arid condition and migration of large numbers of neighbouring taxa from all the neighbourhood areas and farthest region into the Indian subcontinent, as the plants are not restricted by the man made political boundaries and the scenario takes place between this 15 millions years of time. Hooker (1904) while explaining the unique features of the Indian flora (then the British India) stated that "the Indian flora is an admixture of the plants of different adjoining areas like the Chinese and Malayan elements in the east and south; European, Tibetan and Siberian Angiospermic General Restricted in India 147 elements at the north and African, Orientalies and European elements in the west. Later on Hajra and Rao (1990), Rau (1974, 1975), Takhtajan (1969, 1986), Nayar (1980), Rao et al., (1987), Chatterjee (1937), and other workers indicated the relationship and affinity of Indian flora with the floristic components of nearer to farthest regions. During this migration, the migrated plant species come across different climatic as well as edaphic zones, which causes speciation and ultimately forms the endemic species of the Indian floristic components. On the other hand, during the migration process of the species, if the line of migration is cut off by any geological, geographical or ecological means it results in the discontinuous distribution of the same species into two farthest regions. The discontinuous distribution of the species in India and some farthest regions may be taken as a evidence of Paleozoic relationship of India with that zones. MATERIALS AND METHODS In this paper all the restricted angiospermic Indian genera as well as in its neighbouring areas are enumerated. The data are compiled from the available literature and the list is made up to date as far as possible. The synonymy of the genera is excluded here purposely. It is also true that this list is not the complete list in every respect, not only due to lack of data but also because of disagreement over interpretation. More critical studies in future may reduce or increase the numbers accepted here. Here those genera are considered which are restricted in India and its adjoining areas like Sri Lanka, Indomalayan region, Myanmar, China, Tibet, Nepal, Bhutan, Pakistan, Bangladesh, Afghanistan, as well as the genera showing discontinuous distribution with India and Africa, central and eastern Asia, Japan etc. All the genera are enumerated alphabetically under their respective families, which in turn also arranged in alphabetic order. Each genus with its area of distribution and the numbers of species in their credit is also given in the list. Newly formed families with their older names are given in the parenthesis. Distribution of the restricted genera is incorporated in the 'Result and Discussion' chapter. Himalaya stands for the distribution of that genera throughout the Himalayan ranges of different countries. The various abbreviation used in this paper are: Afg.: Afghanisthan, Afr.: Africa, As.: Asia, C: Central, E.: East, W.: West, S.: South, N.: North, Mai.: Malay Province, Indomal: Indomalayan region, Himal.: Himalayan region, Pak.: Pakistan . RESULT AND DISCUSSION . Present study reveals that there are 267 genera with 782 species belonging to 80 families, which are restricted to India and its adjoining areas. Of these restricted taxa of Angiosperms, 72 families belong to Dicots and 8 to Monocots. Dicot families consists of 213 genera with 622 species, whereas Monocot families comprise 54 genera with 160 species (Table-1) 148 Plant Taxonomy : Advances and Relevance Table. 1: Statistical analysis of restricted genera in India and its adjoining Area SI. No. Class No. of families No. of Genera No. of Species 1. 2. Dicotyledons Monocotyledons 72 08 213 54 622 160 3. Total 80 267 782 Detailed enumeration of those restricted genera under their respective families with their area of distribution and the number of species are given in Table.2. Table 2 : List of restrcited genera of India and adjoining areas Names of Taxa I. 1. 2. 3. 4. 5. 6. 7. II. 8. III. 9. 10. IV. 11. 12. V. 13. 14. 15. Acanthaceae Juss. Aechmanthera Nees Calacanthus Anders. ex Benth. Echinacanthus Nees Leptostachya Nees Meyenia Nees Sphinctacanthus Benth. Stenosiphonium Nees Alliaceae Batsh ex Borkh (Liliaceae s.l.) Milula Prain Amaranthaceae Juss. Bosea L. Stilbanthus Hook. f. Anacardiaceae Lindley Dobenia Buch. - Ham. Nothopegia Bl. Annonaceae Juss. Ellipeiopsti R.E. Fries. Sageraea Dalz. Trivalvaria (Miq.) Miq. Distribution Number of Species Himal. Indomal. 3 spp. 1 sp. Himal., China Indomal. India, Sri Lanka N.E. India - Myanmar India, Sri Lanka 4 spp. 1 sp. 1 sp. 1 sp. 3 spp. E. Himal. 1 sp. India, Cyprus, Canary Island Himal. 3 spp. 1 sp. E. Himal., S. China India, Sri Lanka 2 spp. 7 spp. India, S.E. Asia India, Sri Lanka - Philip. Assam to W. Malay 2 spp. 9 spp. 5 spp. Contd. Angiospermic General Restricted in India 149 VI. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. VII. 26. 27. 28. 29. VIII. 30. 31. IX. 32. 33. 34. 35. 36. 37. 38. 39. X. 40. 41. 42. 43. 44. 45. Apiaceae Lindley Acronema Falc. ex Edgew. Chamaesium H. Wolff. Hymenidium Lindley Kedarantha Mukherjee & Const. Lalldhwojia Farille Meeboldia H. Wolff. Oreocome Edgew. Tordyliopsis DC. Trachydium Lindley Vicatia DC. Araceae Juss. Ariopsis Nimmo. Lagenandra Dalz. Lasia. Lour. Trachycarpus Wendl. Araliaceae Juss. Heteropanax Seemann Merrilliopanax H.L.Li Asclepiadaceae Medikus ex Borkh. Antiostelma (Tsiang & P.T. Li) P.T. Li Belostemma Wall. ex Wight Dittoceras Hook. f. Hemidesmus R. Br. Myriopteron Griffith Orthanthera Wight Pentasacme Wall. ex Wight & Arn. Treudera Hook. f. Asteraceae Martinov Artemisiella Ghafoor Bluemeopsis Gagnep Caesulia Roxb. Catamixis Thomson Cavea W. Sm. & Small Dolomiaea DC. Sino - Himal. India, Tibet Himal. Himal. 25 spp. 5 spp. 1 sp. 1 sp. Himal. N. W Himal. Himal. Himal. Himal. Himal., W. China 2 spp. 1 sp. 1 sp. 1 sp. 1 sp. 4 spp. Indomal. India - Sri Lanka Indomal. Himal. 1 sp. 12 spp. 2 spp. 4 spp. India, S. China E. Himal. - S.W. China 2 spp. 3 spp. India, China 2 spp. India, China 2 spp. E. Himal., Thiland. S.E. Asia, Mai. N.E. India - W. Mai. India, Nepal Indomal. 3 spp. 1 sp. 1 sp. 4 spp. 4 spp. E. Himal. 1 sp. Sino-Himal. India - W Mai. India, Pak., Nepal, Myanmar India, Nepal India, Nepal India, Tibet 1 sp. 1 sp. 1 sp. lsp. 1 sp. 14 spp. Contd... 150 Plant Taxonomy : Advances and Relevance 46. 47. 48. 49. 50. 51. XI. 52. XII. 53. 54. 55. 56. XIII. 57. 58. 59. 60. 61. 62. 63. XIV. 64. 65. 66. 67. 68. 69. 70. 71. 72. XV. 73. Dubyaea DC. Goniocaulon Cass. Moonia Arn. Phyllocephalum Bl. Soroseris Stebins Synotis (Clarke) Jaffrey & Chen Balsaminaceae Bercht. & J. Presl. Hydrocera Bl. ex Wight & Arn. Bignoniaceae Juss. Oronylum Vent. Pajanelia DC. Pauldopia Steenis Tecomella Seemann Boraginaceae Juss. Actinocarya Benth. Chinocharis I.M. Thonst. Ivanjhonstonia Kazmi Lacaitaea Brand Lasiocaryum Thonaton Maharanga A. DC. Microula Benth. Brassicaceae Burnett. Arcyosperma Schulz. Atelanthera Hook. f. & Th. Hedinia Ostenf. Lepidostemon Hook. f. & Th. Lignariella Baehi. Loxostemon Hook. f. & Th. Parry odes Tapi. Pyenoplinthus Schulz. Staintoniella Hara Campanulaceae Juss. Cynanthus Wall. ex B.enth. Himal - W. China Indomal. India, Sri Lanka India, Java Himal. - W. China & Tibet Sino. - Himal & China 10 spp. 1 sp. 1 sp. 3 spp. 88 spp. 50 spp. Indomal. 1 sp. Indomal. Indomal. India, S.E. Asia W. India - Arabia 1 sp. 1 sp. 1 sp. 1 sp. India, Tibet, Pakistan Himal. N.W. Himal. E. Himal. Himal., C. As. Himal. (Bhutan, China) Himal.-W, China 2 spp. 1 sp. 1 sp. 1 sp. 7 spp. 8 spp. 6 spp. Himal. W. Himal. 1 sp. 1 sp. India, Nepal, Bhutan, C.As. E. Himal. 1 sp. 1 sp. India, Tibet E. Himal., - S.W. China 2 spp. 1 sp. E. Himal. - S. Tibet Himal. Himal. 1 sp. 1 sp. 2 spp. India, Nepal, Bhutan 19 spp Contd.. Angiospermic General Restricted in India 151 74. 75. XVI. 76. 77. XVII. 78. XVIII. 79. XIX. 80. XX. 81. XXL 82. XXII. 83. 84. XXIII. 85. XXIV 86. XXV. 87. 88. 89. 90. 91. 92. 93. 94. Leptocodon (Hook, f.) Himal. Lemaire Indomal. Peracarpa Hook, f. & Th. Caprifoliaceae Juss. Indomal. Carlemannia Benth. W. Himal. - S.W. China Leycesteria Wall. Caryophyllaceae Juss. Himal. Brachystemma D. Don Celastraceae R. Br. Assam, Myanmar & Thailand Pottingeria Prain Chenopodiaceae Vent. C. & E. As. - Himal. Acroglochin Schrd. ex Schultes Circaeasteraceae Hutch. N.W. Himal. Circaester Maxim. Combretaceae R. Br. Indomal. Getonia Roxb. Convallariaceae Horan. (Liliaceae s.l.) Gonioscypha Baker Himal. Peliosanthes Andrews Indomal. Convolvulaceae Juss. Tridnynamia Gagnep. India - W. Mai. Cornaceae (Dumort.) Dumort. Torricellia DC. E. Himal. - W. China Cucurbitaceae Juss. Biswarea Cogn. Himal. Cucumella Chiov. Trop. Afr. & India Daetyliandra. Hook. f. Kenya & Rajasthan (India) Gomphogyne Griffith E. Himal. - C. China Hemsleya Cogn. E. Himal. - China Herpetospermum Wall, Himal. (Sino. Himal) ex Hook. f. Hodgsonia. Hook, Indomal. f. & Th. Schizopepon Maxim. N.E. India - China 1 sp. 1 sp. 3 spp. 6 spp. 1 sp. 1 sp. 2 spp. 1 sp. 1 sp. 2 spp. 1 sp. 4 spp. 3 spp. 1 sp. 7 spp. 1 sp. 2 spp. 1 sp. 1 sp. 1 sp. 3 spp. Contd. 152 Plant Taxonomy : Advances and Relevance 95. XXVI. 96. XXVII. 97. 98. XXVIII. 99. XXIX. 100. XXX. 101. XXXI. 102. 103. 104. XXXII. 105. 106. XXXIII. 107. XXXIV. 108. 109. 110. XXXV. 111. 112. 113. 114. 115. Zonnonia L. Cyperaceae Juss. Actinoscirpus (Ohwi) R. Hains & Lyc. Diapensiaceae Lindley Berneuxia Decne. Diplarcha Hook. f. & Th. Dioscoreaceae R. Br. Trichopus Gaertner Dipentodontaceae Merr. Dipentodon Dunn Dipterocarpaceae Blume Valeria L. Euphorbiaceae Juss. Epiprinus Griffith Mischodon Thw. Pactiystylidium Pax & K. Hoff. Flacourtiaceae Rich. Gynocardia R. Br. Hemicolopia Slooten Fumariaceae Bercht. & Prest. Daetylicapuos Wall. Gentianaceae Juss. Taeschkea Kurz Megacodon (Hemsley) H. Sm. Veratrilla Ballion ex Pranchet. Gesneriaceae Rich. & Juss. ex DC. Briggsia Craib Leptobaea Benth. Loxostigma Clarke Platystemma Wall. Tetraphyllum Griffith ex Clarke Indomal. 1 sp. Indomal. 1 sp. Himal. E. Himal. & S.W. China 1 sp. 2 spp. Indomal. 1 sp. India, Myanmar & China 1 sp. India & Sri Lanka 2 spp. Assam - W. Mai. India & Sri Lanka India & C. Mai. 6 spp. 1 sp., 1 sp. India, Bhutan, Bangladesh, Myanmar Indomal. 1 sp. Himal. 10 spp. Himal. Himal. 3 spp. 1 sp. E. Himal - W. China 2 spp. E. Himal., Myanmar, China 2 Himal. & 1 Borneo E. Himal. Himal. N.E. India -TJiiland 14 spp. 3 spp. 4 spp. 1 sp. 2 spp. 1 sp. Contd... Angiospermic General Restricted in India 153 XXXVI. 116. Hamamelidaceae R. Br. Parrotiopsis (Niedeuzu) C. Schieider 117. Sycopsis Oliceer XXXVII. Icacinaceae (Benth.) Miers 118. Natsiatum Buch.-Ham. ex Arn. XXXVIII. Tuglandaceae DC. ex Perleb 119. Engelhardtia Leschen ex Blume XXXIX. Lamiaceae Martinov 120. Colebrookea Sm. Colquhonia Wall. 121. 122. Craniotome Reichb. 123. Cymaria Benth. 124. Eriophyton Benth. Holmskioldia Retz. 125. 126. Hymenopyramis Wall. ex Griffith 127. Leucoseptrum Sm. 128. Meriandra Benth. Notochaete Benth. 129. Roylea Wall, ex Benth. 130. XXXX. Lardizabalaceae R. Br. Decaisnea Hook. f. & Th. 131. Lauraceae Juss. XLI. 132. Dodecadenia Nees Apollonias Nees 133. Parasassafras Long 134. XLII. 135. 136. 137. 138. 139. Leguminosae Juss. Acrocarpus Wight ex Arn. Amherstia Wall. Cochlianthus Benth. Dalhousiea Wall. ex Benth. Endosamara Geesink Himal. 1 sp. Assam - Taiwan 2 spp. Himal. & Tarai region 4 spp. Himal. - Mai. 5 spp. N.W. Himal. & China E. Himal. - S. W. China Himal. Indomal. Himal. Himal. India - China 1 sp. 3 spp. 1 spp. 2 spp. 1 sp. 1 sp. 6 spp. Himal.-China Himal. & Ethiopia Himal. Himal. 3 spp. 2 spp. 1 sp. 1 sp. E. Himal. - C. China 1 sp. Himal. India, Macronesia Himal. - Myanmar & W.China 1 sp. 1 sp. 2 spp. Indomal. Myanmar Himal. N.E. India & Bangaladesh 1 sp. 1 sp. 2 spp. 1 sp. Indomal. 2 spp. Contd. 154 Plant Taxonomy : Advances and Relevance 140. 141. 142. 143. 144. 145. XLIII. 146. XLIV. 147. 148. XLV. 149. XLVI. 150. XLVII. 151. XLVIII. 152. 153. 154. XLIX. 155. 156. L. 157. LI. 158. 159. 160. 161. LII. 162. LIII. 163. India, Nepal Indopiptadenia Breman Assam - C. Mai. Mastersia Benth. Indomal. Mecopus Bennet Himal. Piptanthus Sweet Himal. Stracheya Benth. Indomal. Tadehagi Ohashi Liliaceae Juss. Assam, Myanmar & China Nomocharis Franchet. Linaceae DC. ex. Perleb Himal. & China Anisadenia Wall. ex Meiss N. India & China Reinwardtia Dunn Loranthaceae Juss. India, Sri Lanka & China Tolypanthus Blume Lythraceae J. St. Hil. Indomal. Hydrolythrum Hook. f. Magnoliaceae Juss. Assam, W. Mai. Pachylarnax Dandy Malvaceae Juss. India & Sri Lanka Tulostylis Thw. S.E. As. Kydia Roxb. Himal. & China Nayariophyton Paul Melastomataceae Juss. India & Sri Lanka Kendrickia Hook. f. Pscudodissochaeta Nayar N. India, Sri Lanka Meliaceae Juss. Himal. Sphaerosacme Wall. ex Royle. Menispermaceae Juss. Indomal. Anamitra Colesr N.E. India & S.W. China Aspidocarya Hook. f. & Th. India, China Eleutharrheua Formann Himal. - Mai. Haematocarpus Mies. Morinaceae Raf. (-Valerianaceae) Sino-Himal. Acanthocalyx (DC.) Tieghen. Myristicaceae R. Br. Indomal. Endocomia Wilde. 1 sp. 2 spp. 1 sp. 2 spp. 1 sp. 3 spp. 7 spp. 2 spp. 2 spp. 3 spp. 1 sp. 2 spp. 2 spp. 1 sp. 1 sp. 1 sp. 4 spp. 1 sp. 1 sp. 1 sp. 1 sp. 2 spp. 3 spp. 4 spp. Contd... \ Angiospermic General Restricted in India 155 LIV. 164. 165. LV. 166. LVI. 167. 168. LVII. 169. 170. LVIII. 171. 172. 173. 174. 175. 176. 177. 178. 179. 180. 181. 182. 183. 184. 185. 186. 187. 188. 189. 190. 191. 192. Myrsinaceae R. Br. Amblyanthopsis Mez. Hymenandra A. DC. Olacaceae Martinov Erythropalum Bl. Oleaceae Hoffsgg. & Link Nyctanthes L. Myxopysum Bl. Opitiaceae (Benth.) Valeton (-Olacaceae Martinov) Champereia Griffith Lepinurus Bl. Orchidaceae Juss. Androcorys Schlr. Anlhogonium Wall. ex Lindley Aorchis Vermeulen Bulleyia Achltr. Bierrnannia King & Pantl. Cleisocentron Bruhl Cottonia Wight Crypldchilus Wall. Crytosia Bl. Dioticiea King & Prain Diplylax Hook. f. Diplomeris D. Don Eriodes Rolfe. Esmeralda Reichb. f. Herpysma Lindley Ipsea Lindley Monomeria Lindley Neogyna Reichb. f. Orcochis Lindley Panisea (Lind.) Studel Parapteroceras Averynoo Sirhookeris Kiintze Himal. Indomal. 2 spp. 2 spp. Indomal. 1 sp. India, Java Indomal. 2 spp. 4 spp. Indomal. Indomal. 1 sp. 1 sp. India, E. As. India, S.E. As. 4 spp. 1 sp. Himal. Himal. - S.W. China India, China lsp. 1 sp. 7 spp. Himal S. India & Sri Lanka Himal. Indomal. E. Himal., Japan N.E. India - China Himal. N.E. India - Vietnam Himal. & S.E. As. India, Philippins India & Sri Lanka Himal., S.E. As. N.E. India & S.W. China Himal. & Japan S.E.As. & India Indomal. l p. 1 sp. 6 spp. 5 spp. 2 spp. 1 sp. 2 spp. 2 spp. 2 spp. 1 sp. 2 spp. 2 spp. 1 sp. 9 spp. 7 spp. 3 spp. S. India & Sri Lanka 2 spp. S Contd... 156 Plant Taxonomy : Advances and Relevance 193. 194. 195. 196. 197. LIX. 198. LX. 199. LXI. 200. LXII. 201. 202. 203. 204. 205. 206. 207. 208. 209. 210. 211. 212. 213. 214. 215. 216. LXIII. 217. LXIV. 218. Tapobanea Christ Thecopus Scidenf. Thunia Reichb. f. Trudelia Garay Uneifera Lindley Orobanchaceae Vent Gleadovia Gamble & Prain Papaveraceae Juss. Dicranostigma Hook, f. & Th. Plumbaginaceae Juss. Dictyolimon Reichb. f. Poaceae Carnel Borinda Stapleton Dichaetaria Nees ex Steudl. Dignathia Stapf. Duttiea Hackl. Hygroryza Nees Jansenella Bor Lasiurus Boiss. Lopholepis Decne. Melocanna Trin. Mnesithea Kunth Myriostachya (Benth.) Hook. f. Ochlandra Thw. Pommereulla L. f. Porteresia Tateoka Trachys Pers. S. India & Sri Lanka Indomal. Himal., Mayanmur India, Thiland India - W.Mai. 1 sp. 2 spp. 5 spp. 5 spp, 7 spp. Himal. & China 6 spp. Himal. & China 5 spp. India & Afg. 4 spp. Himal. India & Sri Lanka 8 spp. 1 sp. E.Afr. & W India Himal., Afg. & China India & Sri Lanka India & Sri Lanka N.E. India - Mai. India & Sri Lanka Indomal. Indomal. India & Sri Lanka 5 spp. 3 spp. 1 sp. 1 sp. 1 sp. 1 sp. 3 spp. 1 sp. 1 sp. India & Sri Lanka India & Sri Lanka India & Myanmar S. India, Sri Lanka & Coastal Myanmar India & Sri Lanka 7 spp. 1 sp. 1 sp. 1 sp. Zenkeria Trin. Podostemonaceae Rich. ex Kunth India & Sri Lanka Farmeria Willis. ex Trimen Primulaceae Batsch. ex Borkh Himal. Bryocarpum Hook. f. & Th. 4 spp. 2 spp. .- 1 sp. Contd... Angiospermic General Restricted in India 157 LXV. 219. Ranunculaceae Juss. Archiclematis (Tamura) Tamura Calathodes Hook. 220. f. & Th. Paronygraphis W.W.Sm. 221. Naravelia Adans. 222. Rosaceae Juss. LXVI. Docynia Decne. 223. Maddenia Hook. f. & Th. 224. Rubiaceae Juss. LXVII. Fergusonic Hook. f. 225. Brachytone Hook. f. 226. Byrsophyllum Hook. f. 227. Clarkella Hook. f. 228. Discospermum Dalzell 229. Dunnia Tutcher 230. Duperrea Pierre 231. ex Pitrad. 232. Fagerlindia Tirveng Hydrophylax L.f. 233. 234. Hyptianthera Wight & Am. Indopolysolenia Bennett. 235. Keenania Hook. f. 236. Luculia Sweet 237. Metadina Bakh. f. 238. Neolymenopon Bennett. 239. Heurocalyn Hook. 240. 241. Ochreinauclea Risad & Bakh. f. 242. Octotropis Bedd. Meiocraterium Bremak. 243. LXVIII. Rutaceae Juss. 244. Chloroxylon DC. Pamlrunis Swingle 245. Pleipspermium (Engl.) 246. Swingle Sapindaceae Juss. LXIX. Euphorianthus Radlk. 247. Xerospermum Bl. 248. Himal. 1 sp. Himal. & Taiwan 3 spp. Himal. Indomal. 1 sp. 1 sp. Himal. & S.E.As. Himal. & China 2 spp. 4 spp. India, Sri Lanka Indomal. India, Sri Lanka Himal.-Thiland Indomal. India & China India & China 1 sp. 4 spp. 2 spp. 2 spp. 6 spp. 2 spp. 2 spp. India - W.Mai. India & Sri Lanka N. India, Thiland 6 spp. 1 sp. 2 spp. E. Himal. & Myanmar India, S.E.As. Himal. & China Indomal. Himal. India, Sri Lanka Indomal. 2 spp. 5 spp. 5 spp. 1 sp. 3 spp. 6 spp. 2 spp. India & Myanmar S. India & Sri Lanka 2 spp. 4 spp. S. India & Sri Lanka S. India & Sri Lanka S. India & Sri Lanka 1 sp. 1 sp. 5 spp. Indomal. * Indomal. 1 sp. 2 spp. Contd... 1,58 Plant Taxonomy : Advances and Relevance LXX. 249. 250. LXXI. 251. 252. 253. 254. 255. Sapotaceae Juss. Isonandra Wight Xantolis Raf. Scrophulariaceae Juss. Bgthophyton Hook. f. Kashmiria Hong. Neopicrorhiza Hing. Orcosolen Hook. f. Picrorrhiza Royle ex Benth. 256. Wightia Wall. 257. Wulfeniopsis Hong. LXXII. Simaroubaceae DC. Eurycoma Jack 258. LXXIII. Sterculiaceae DC. Pentapetes L. 259. LXXIV. Theaceae Mirbel ex Ker. Gawler 260. Dankia Gagnep. LXXV. Thymelaeaceae Juss. 261. Enkleia Griffith 262. Eriosclena Bl. LXXVI. Tiliaceae Juss. 263. Berrya Roxb. LXXVII. Yrticaceae Juss. 264. Aboriella Bennett. LXXVIII. Valerianaceae Batsch 265. Nardostachys DC. LXXIX. Viscaceae Batsch. Ginolloa Korth. 266. LXXX. Zingiberaceae Martinov 267. Cautleya Hook. f. 268. Mantisia Sims. S. India & Sri Lanka India-Philippines 10 spp. 14 spp. Indomal. Himal. Himal. Himal. W. Himal. 1 sp. 1 sp. 1 sp. 3 spp. 1 sp. Indomal. Indian, Afg., Pak., Nepal 2 spp. 2 spp. Indomal. 3 spp. Indomal. 1 sp. India & S.E.As. 1 sp. Andaman & S.E.As. E. Himal., China & Java 3 spp. 5 spp. India & Sri Lanka 5 spp. Himal. 1 sp. Himal. 1 sp. Indomal. 8 spp. Himal. Indomal. 5 spp. 3 spp. On the basis of present survey it reveals that the Orchidaceae is the most diversified family which has highest (27) number of restricted genera followed by Rubiaceae, Poaceae, Asteraeeae, Lamiaceae etc. and on the basis of the number of the species, Asteraceae is the most diversified family followed by Orchidaceae, Rubiaceae, Apiaceae etc. (Table 3). Present analysis also reveals that most of the restricted genera are represented by a single representative and there is only one genus {Synotis (Clarke) Jaffrey & Chen., Asteraceae} which possesses 50 species. A comparative amount of species diversity within the restricted genera are shown in Table 4. Angiospermic General Restricted in India 159 It is interesting to note that the comparatively advanced families show great diversity both at the generic and species level, whereas primitive families are poorly diversified. A comparative account of diversification of primitive and advanced families is given in Table 5. Table 3 : Numerical analysis of the diversified families on the basis of their number of restricted genera and species there in, in India and its adjoining areas SI. No. Name of families No. of restricted genera SI. No. Name of families No. of restricted. species 1. 2. 3. 4. 5a. 5b. 6. Orchidaceae Rubiaceae Poaceae Asteraceae Lamiaceae Fabaceae Apiaceae 27 19 16 12 11 11 10 1. 2. 3. 4. 5. 6. 7. Asteraceae Orchidaceae Rubiaceae Apiaceae Poaceae Lamiaceae Fabaceae 92 83 58 42 40 22 17 Table 4 :' Comparative account of species diversity within the restricted genera of India SI. No. Categories of Genera No. of Genera 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. Genera with 1 species Genera with 2 species Genera with 3 species Genera with 4 species Genera with 5 species Genera with 6 species Genera with 7 species Genera with 8 species Genera with 9 species Genera with 10 species Genera with 12 species Genera with 14 species Genera with 19 species Genera with 25 species Genera with 50 species Genera with 1 species 124 55 24 17 14 9 8 4 2 3 1 3 1 1 1 1 160 Plant Taxonomy : Advances and Relevance Table 5 : Comparative account of diversification of primitive and advanced families of India and its adjoining areas SI. No. Name of advanced families No.of genera No.of species SI. Name of No. primitive families No.of genera No.of species 1. 2. 3. 4. 5. 6. 7. Apiaceae Asteraceae Fabaceae Lamiaceae Orchidaceae Poaceae Rubiaceae 10 12 11 11 27 17 19 42 92 17 22 83 40 58 1. 2. 3. 4. 5. 6. 3 1 2 1 4 4 16 1 3 2 5 6 Annonaceae Circaeasteraceae Hamamelidaceae Magnoliaceae Menispermaceae Ranunculaceae By analysing the data, it can be concluded that the primitive families are confined to those regions which are very old in geological time scale in comparison to the newly developed areas. On the basis of this observation, it can be stated that the Assam, North East Indian region and Deccan Peninsula are older in comparison to the other phytogeographical regions of India, and these regions are more or less identical in age with Sri Lanka,. South West Chinese region and Malay Peninsula. It is also concluded that the Deccan Peninsula shows its floristic relationship with Sri Lanka and Malay provinces, while the North East India shows its floristic relationship with Myanmar, South West Chinese provinces and Malay Peninsula. So the Malay region shows similarity with Deccan Peninsula on one hand and the North East India on the other, and by this way the North East India shows similarity with Deccan Peninsula to some extent. On the other hand, the advanced families are found in those regions which are comparatively very young in the geological time scale. So, on the basis of this idea it can be stated that the Himalayan region of India is very young in its age in comparison to the Deccan Peninsula and North East Indian regions of India, as it harbours most of the advanced families with well diversified restricted genera and species. This type of distribution and diversification of advanced and primitive families can be classified under the light of "age and area" hypothesis of Willis (1922). As the advanced families are young in their age, as well as they are confined to the areas which are also geologically young, they are unable to spread in the wider regions. On the other hand, the primitive families are older in their age, also found to confined in those areas which are geologically very old. So they get enough time to spread over larger areas, as a result of which the primitive families show less number of restricted genera and species in their credit in comparison to the advanced families. On the basis of the nature of distribution of the restricted genera in India and its adjoining areas, it can be concluded that the plants are not bounded by the man made boundary as a Angiospermic General Restricted in India 161 result of which the plants are migrated in the Indian political boundary from its neighbouring countries or vice versa and shows floristic affinities with those regions. Though northern part of India is bounded by the world's highest and longest mountain ranges, the great Himalayas, it cannot prevent the migration of the plants into the Indian regions from its other side, which can be evidenced by the presence of the Trans-Himalayan genera and the other genera with discontinuous distribution. During this type of migration through different channels and corridors of Himalayan region, plants suffer varied types of climatic as well as physiographic condition, as a result of which in the Himalayan region speciation is a continuous process (Hara, 1975). So this area is rich in restricted genera, many of which are also endemic to this region. The eastern Himalayan region is more important floristically than its western part, owing to the presence of cold desert areas in a major portion of western Himalayas. So, floristically it is not so rich as its eastern counter part. In this context, Takhtajan's opinion regarding Himalayas (Eastern Himalayas) is "the cradle of Angiosperms", which is also proved correct. Besides this, the present analysis provides support to treat the Khasi-Manipur and eastern Himalayan region as two separate phytogeographic provinces and incorporation of Andaman Island into Indo-Chinese region and the Nicobar Island into Malay province by Takhtajan (1986) is correct. LITERATURE CITED Balakrishnan, N.R 1996. Phytogeographic divisions: general considerations. In Hajra, P.K. et al. eds. Flora of India (Introductory volume), Part I, B.S.I. Calcutta. Chatterjee, D. 1937. Influence of East Mediterranean region flora on that of India. Sci. & Cult. 13:9-11. Hajra, P.K. and R.R. Rao 1990. Distribution of vegetation types in North West Himalayas with brief remarks on phytogeography and floral resources conservation. Proc. Indian Acad. Sci. (PI. Sci.) 100 (4): 263-277. Hara, Ohasi. 1975. Flora of Eastern Himalayas. Third report. Tokyo. Hooker, J.D. 1904. A Sketch of the Flora of British India. London. Karthikeyan, S. 2000. A Statistical Analysis of Flowering Plants of India. In Singh, N.P. et al. eds. Flora of India (Introductory volume). Part - II: pp 201-217. B.S.I. Calcutta. Nayar, M.P. 1980. Endemism and pattern of distribution of endemic genera (Angiosperms) in India. J. Econ. Taxon. Bot. 1: 99-100. Rao, T.A. and S. Chakraborty, 1987. Distribution resume of coastal Floristic elements in the Andaman and Nicobar Islands. Curr. Sci. 56: 1045-1051. Rao, M.A. 1974. Vegetation and phytogeography of the Himalayas. In: Mani, M.S. (ed.), 1974, Ecology and Biogeography in India, pp. 204-246 and 247-280. Dr. W. Junk, B.V. Publisher, The Huge. Rau, M.A. 1975. High altitude flowering plants of Western Himalayas. BSI, Calcutta. Razi, B.A. 1959. A second list of species and genera of Indian Phanerogams not included in J.D. Hooker's Flora of British India. Bull. Bot. Surv. India 5: 79-88. 162 Plant Taxonomy : Advances and Relevance Takhtajan, A. 1969. Flowering Plants, Origin and Dispersal. Edinburgh. Takhtajan, A. 1986. Floristic regions of the world. Bishen Singh Mahendra Pal S Publication, Dehra Dun (reprinted). Willis, J.C. 1922. Age and Area. Cambridge University Press, Cambridge.