Agharkar Research Institute,
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Palms (Family Palmae / Arecaceae) constitute a large assemblage of a majestic arborescent plants distributed mainly in the Oceanic Islands
and coastal areas in the tropics between 400 North and 400 South of the equator. Family Palmae, according to Benthem and Hooker s system of classification, is placed in the series Calycine along with families Flagellariaceae and Juncaceae in between the series Coronarieae (Liliaceae and Pontaderiaceae) and Nudiflorae (Pandanaceae, Cyclanthaceae, Typhaceae, Araceae and Lemnaceae). There are about 2364 species belonging to 190 genera distributed in six subfamilies, Coryphoideae, Calamoideae, Nypoideae, Ceroxyloideae, Arecoideae and Phytelephantoideae. There are 135 species of indigenous palms and more than 150 introduced species in India. Palms play a significant role in human welfare and are ranked next to Poaceae and Leguminosae as far as the basic necessities like food, shelter and other utilities are

Uniqueness of Palmae is characterized by having (i) arborescent plants with massive unbranched stem (except Hyphaene) capped with a crown of large sized pinnate or palmate leaves, huge inflorescences, fruits and seeds, green perianth, superior ovary, albuminous endosperm and 16-18 chromosomes; (ii) absence of secondary growth. The stem exhibit enhanced primary growth consisting irregularly scattered vascular bundles in the parenchymatous ground tissue. The girth of the stem increases due to expansion of ground parenchyma cells; (iii) leaf of Raphia ruffia is the longest in the plant kingdom about 25 meters in length; (iv) inflorescences of Corypha umbraculifera, Metroxylon sagu, Caryota urens are the largest inflorescences; (vi) seed of Lodoicea maldevica is the largest seed in the plant kingdom. It is about 45-50 cm long and 35-40 cm in diameter weighting 10-12 kg and require 12-15 years for maturity. Cocos nucifera coconut palm, Areca catechu
arecanut palm, Phoenix sylvestris- wild date palm, P. dactylifera date palm, Borassus flabellifer palmyra palm, Caryota urens fish tail palm, Elaeis guineensis African oil palm, Metroxylon sagu sago palm, Ceroxylon ceriferum wax palm, Arenga saccharifera the economically important palms. Hyphane dichotoma doum palm is the only naturally dichotomously branched palm. Corypha umbraulifera, Chrysalidocarpus lutescens, Ptychosperma elegans, Roystonea regia, Livistona chinensis, Licuala grandis, Pritchardia pacifica, Rhapis excelsa , Chamaedorea pinnatiformis are the palms with aesthetic beauty that adorn the house premises and public and private gardens.

The palms show a wide range of ecological adaptations and behavior by exhibiting great morphological diversity. Nypa fruticans, Phoenix paludasa form dense colonies in estuarine muds. Hyphaene dichotoma, Calamus eriananaceous, Daemonorops longispatha, Raphia taediagera grow on the landward fringe of the mangrove. Copernicia alba grows in periodic flooding and drought areas. Metroxylon sagu,
Corypha umbraculifera, Areca catechu, Cocos nucifera grows at the lowland rain forest area in tropics. Caryota urens, Phoenix reclinata, Ceroxylon sp., Dictyocaryum sp., Nannorhops sp., Trachycarpus sp. grows at the mountain forests. Chamaerops humilis is the only palm native to Europe. Rhopalostylis sapida grows at the southern most limit in New Zealand.

Palms have a very long geological history; originated in the Cretaceous period, if not earlier. Their fossils are known from different parts of world such as Belgium, France, England, Holland, Hungary, Italy, Romania, Mexico, Canada, U.S.A., Egypt, Libya, Japan, India, Burma, Sri Lanka, Sumatra and Australia. India is very rich in having palm fossils in different horizons from Cretaceous onward periods, especially the
Deccan Intertrappean beds of Central India. They occur as permineralizations, impressions, compressions and casts of different plant parts such as stem, root, leaf, inflorescence, flower, fruit, seed and pollen grains assigned to organ genera such as Palmoxylon Schenk for stem; Rhizopalmoxylon Felix for root; Parapalmocaulon Bonde, Phoenicicaulon Bonde et al., Sabalocaulon Trivedi & Verma for petiole; Amesoneurson Goppert, Bactrites Berry, Sabalites Saporta, Palmacites Brongniart, Phoenicites Brongniart, Paloreodoxites Knowlton, Propalmophyllum Lignier,
Sabalophyllum Bonde for the leaves; Palmostroboxylon Biradar & Bonde for inflorescence axis; Arecoideostrobus Bonde for rachilla; Deccananthus Chitaley & Kate for flower; Palmocarpon Miquel, Nipadites Bowerbank, Hyphaeneocarpon Bande et al., Engeissonocarpon Shinde & Kulkarni, Arecoidocarpon Bonde for fruits; Palmospermum Reid & Chandler, Caryotispermum Reid & Chandler for seeds and
Spinizonocolpites Muller, Palmaepollenites Potonie, Verrumonocolpites Pierce, Quilonipollenites Rao & Ramanujam for pollen grains.
Sanmiguelia lewisii Brown (Brown, 1956; Tidwell et al., 1977; Cornet, 1989 is a problematic record of a palm from the Triassic period of Colorado, U.S.A. Palmoxylon (Cocos) sundaram Sahni (Sahni, 1946; Bonde et al., 2004) is the classical example of reconstruction of a five meter tall palm trunk with aerial stem and rooting region. Mahabalea phytelephantoides Bonde is a massive juvenile palm axis with roots, stem and a crown of leaves in trimerous spiral phyllotaxy. Absence of vessels in its stem suggests the early evolution and diversification of palm in the Upper Cretaceous (Maastrichtian) period in Central India.

Palms represent the earliest forms in monocotyledons and show many specialized structures and evolutionary trends unique to it amongst the angiosperms.The first palms might have originated when the two continents, Gondwana and Laurasia were yet to be separated. The fossil record indicate that by Eocene time they were wide spread in India, China, Europe, North and South America. Further studies of distribution and relationship of extant palms, fossils and of geological data are greatly required for the understanding of palms in time and space.

Key Words: Palmae, Diversity, Fossils