I. INTRODUCTION

Leguminosae is one of the three largest families of flowering . It includes varying numbers of genera and species ranging from 550-690 genera and 12,000-17,000 species (Airy Shaw, 1966; Hutchinson, 1964 and Melchior, 1964). It is well represented in tropical and sub-tropical countries, being most numerous in tropical America. The great number of genera of Caesalpiniaceae occur in tropical Africa and tropical America. In tropical Africa about fifty six and in tropical America about forty are being endemic (Hutchinson, I964). As many as two hundred species of Cassia L. alone are represented in the flora of Brazil (Rendle, 1925). Only about eight genera occur in both tropical Africa and America. In Malaya, New Guinea and tropical Asia there are about eleven genera. In Madagaskar there are nine endemic genera. It is poorly represented in Polynesia, South China, Australia and extra tropical region of South America; while in north temperate zone only about three genera occur. A few genera have a distribution of special interest, viz., Dalhousie_a d. Grah. in India and Western tropical Africa; Bowringia Champ, ex Benth. in East Asia and Vi/estern tropical Africa; Calpurnia E. Mey. in South India and Africa, Gladrastis Rafin in North East and Eastern Asia. Miraosaceae is mainly of Southern Hemi­ sphere. Most of the African genera seem to be more modern development of the group, the headquarters of which is in South America. In the Papilionaceae, Wiich is world wide in distribution; the more primitive woody genera are confined to the Southern Hemisphere and to the tropics, the more advanced and herbaceous genera to temperate regions and numerous Mediterranean countries. The tropical rain forests are rich in species of Caesalpiniaceae and Mimosaceae along with arborescent forms of the Papilionaceae (Tribe - Dalbergieae). In deciduous forests where the growth is interrupted by cold vdnter, leguminous trees are rare; herbaceous Papilionaceous members become more important features of vegetation in such regions. Papilionaceous members play important role in Steppe formations.

The family is well circumscribed, showing significant evolutionary tendencies in the leaf type, carpel morphology and number, zygomorphy and reduction of floral parts. However, opinions have sharply differed as regards the status and posit ion of it and the inclusion of the three sub-families, Gaesalpinoideae, Mimosoideae, Lotoideae (Papilionoidaae, , Papilionatae ) and the fourth sub-family Swartzioideae, in it. They are recognised some­ times as separate families - Caesalpiniaceae, Mimosaceae, (Papilionaceae) and Swartziaceae. Bentham and Hooker (1^55) treated Leguminosae as an Order in their "Genera Plantarum", dividing Order into sub-orders - Papilionaceae, Caesalpiniaceae and Mimosaceae. jummosae divided into the and Mimosaceae. In the classification of Taubert (1894) given in Engler and Prantl's (1894) "Die Naturlichen Pflanzen Familien", Leguminosae is divided into three sub-families, viz., Mimosoideae, Caesalpinoideae and Papilionatae. Taubert (1894) considered Mimosoideae first under Legumi­ nosae; while same group of plants was treated as the third by Benthara and Hooker (1865) and Baker (187&). But there was no dispute about the position of Caesalpinoideae as it was ranked as second by them. Bessey (1915) included number of families in the Order )sales. He treated Mimosaceae in the Order ^sales. He treated Mimosaceae, Gassiaceae and Fabaceae as the families of the Order Resales, but substituted the terms Gassiaceae for Caesalpiniaceae and fabaceae for Papilionaceae. Hutchinson (1926) considered Leguminosae as an Order and remarked "a prolific and highly successful group derived from the Resales though the Mimosaceae, Caesalpiniaceae and Papilionaceae as the families of the Order Leguminales." But in 1964, he (Hutchinson, 1964) modified his previous views regarding the origin of Leguminosae and suggested that the Caesalpiniaceae was the most primitive family in this Order and was clearly related to the liosaceae. He connected the genus Bauhinia L. of Gaesalpiniaceae, to the tribe Chrysobalaneae; which is the most advanced tribe of Rosaceae. In the tribe Chrysobalaneae, the flowers are zygomorphic and fruits resemble legumes. Hutchinson (1954) considered Papilionaceae as the most advanced family of the Order Leguminales. Schnarf (1931) included Mimosaceae and Papilionaceae as fam.ilies under Order Resales, but considered Caesalpi- noideae and Papilionatae as two sub-families of Papilionaceae. Warming (1932) recognised these as three families and treated them in one sequence Gaesalpiniaceae, Papilionaceae and Mimosaceae. Wettstein (1933~193 5) recognised Mimosaceae and Leguminosae as the families but treated Gaesalpinoideae and Papilionatae as sub-families of Leguminosae. Wodehouse (193 5) followed Wettstein. Bailey (1949) considered Leguminosae as family that included the sub-families - Lotoideae, Gaesalpinoideae and Mimosoideae. Gundersen (1950) followed Wettstein in treating Gaesalpinoideae and the Papilionatae as the sub-families of Leguminosae, but treating Mimosaceae as a family at par with Leguminosae. Johansen (1950) treated Leguminales as an Order that included three families Gaesalpiniaceae, Mimosaceae and Papilionaceae (Fabaceae). Lawrence (1951) accepted Mimosaceae, Caesalpiniaceae, and Lotoideae as sub-families of the family Leguminosae. Rendle (1925 ) considered Leguminosae as family com­ prising of three sub-families viz., Miraosoideae, Caesalpinoideae and Papilionatae. Metcalfe and Chalk (1950) treated Mimosaceae, Caesalpiniaceae and Papilionaceae as the families of Leguminosae. From the anatomical data they considered Mimosaceae as least specialised and Papilionaceae as highly specialised. But the position of Caesalpiniaceae is intermediate between the two. The structure of wood has been held to be fairly diagnostic in seggregating these three sub-families (Metcalfe and Chalk, 1950). It is also suggestive of the degree of specialisation and therefore of phylogenetic sequence. Mimosoideae is held to be least highly specia­ lised in this regard and the Papilionatae the most highly specialised. Dnyansagar (1956) discussed the status of Leguminosae. According to him Leguminosae should be treated as an Order and not a family. In order to support his views, he (Dnyansagar, 1956) gave embryological, cytological and anatomical evidences and considered Mimosaceae and Caesalpiniaceae as families but suggested that Papilionaceae being a heterogeneous group shoulc further be divided into more than one family. Takhtajan (1969) recognised three families, viz., Mimosaceae, Caesalpiniaceae and Fabaceae of the Order and used the word 'Fabales' for Leguminales. i

On the basis of cytological evidences, many cytologists tried to consider the relationships in Leguminosae. Senn (1938, 1943) tried to trace the relationships between Mimosaceae, Caesalpiniaceae and Papilionaceae. However, he was not successful in doing so on account of the in­ adequate cytological work in Mimosaceae and Caesalpiniaceae.

Atchinson (1947, 194^, 1951) studied the chromosome numbers of about II4 species of Leguminosae. According to her Mimosoideae is the most prim.itive of the three families and Papilionatae is the highly advanced sub-family. The flower structure and basic chromosome numbers suggested the link of Caesalpinoideae with Podalyrieae. Perhaps all three sub-families arojjse from similar ancestral proto­ types, but the prototypes were not found in the living representative and the indisputable link between the three sub-families was the poa character. Thus delimited, the family Leguminosae has enjoyed a more or less, constant position and stable status. Taxo- nomists are in agreement in placing the family unaer Resales (Bentham and Hooker, 1862-1883; Taubert, 1894; Bessey, 1915; Rendle, 1925; Engler and Uiels, 1936; Lawrence, 1951; Cronauist, 1968; Takhtajan, 1967, 1969) with obvious affinities with Connaraceae (Bentham and Hooker, 1862-1883; Bessey, 1915) of Chrysobalanaceae of the Rosaecae. Hutchinson (I964) raisea the status of the family to an \) ordinal rank Leguminales, but Takhtajan (1967, 1969) and Gronquist (1968) maintained its family rank under Resales. le' reTative positSn of the three s'uB-families or the families comprising the family Leguminosae or the Order Leguminales respectively with an obvious indication of Phylogenetic sequence, has been a matter of some dispute. It is of interest to read Bentham (Bentham and Hooker, 1^62-1^^3) and Hutchinson (1964) in this connection (Bentham and Hooker, 1852-1^^3) wrote about Leguminosae- "A vast family (Orders), very natural, divided into three sub­ families (Sub-Ordinatus) by sufficiently well defined characters." Amongst so many species, there are very few which are ambiguous between the Papilionaceae and Caesal­ piniaceae and between the later ana the Mimosaceae. Hutchinson (1964), however comr'ients: "it is merely a matter of opinion or conscience (or even of prejudice] ) whether Caesalpiniaceae should be treatea a separate family from Mimosaceae and Fabaceae (Papilionaceae) or all three regarded as sub-families of Leguminosae." It is a fallacy to assume that all of this group have the fruit - 'a legume', very many have not. Botanists fortunately are not hide­ bound by rules in such matters and are free to please themselves. No one is correct in such cases.

Most of the authors have considered Mimosoideae as the relatively primitive taxon (Tauburt, 1894; Bessey, 1915; Rendle, 1925 etc.) while Hutchinson (1964) has emphasized the primitiveness of Caesalpiniaceae which shows characters akin to Chrysobalanaceae of the Rosaceae. He further considered that the tv/o families Caesalpiniaceae and Mimosaceae have evolved independently from a common ancestor along with Chrysobalanaceae. Corner (1951) divided family Leguminosae on the basis of seed structure into sub-families viz.: Mimosoidae, Caesalpinoideae, Swartziodeae and Papilionatae. Leguminous seeds have been favourite of anatomists (Corner, 1951). Large seeds with brightly coloured aril were held to be primitive. (Hallier, 1912; Corner, 1949) and the genus Durio which associates the primitive seed character with arborescent habit; also considered to be primitive. Bancroft (1930) and Corner (1951) postulated the "Durian Theory". Eames (1961) however, seems sceptical about the idea as size of the seed is held to be of little importance in the determination of phylogenetic tendencies and posses­ sion of aril, a character that shared by several diverse taxa.

Krameria, the only genus of its type, was placed in Polygalaceae by Benthara and Hooker (1862-1883), but Taubert (1894) assigned it to the rank of tribe under Caesalpinoiaeae, Britton (1930), however, raised, the tribe "Kramerieae" to the status of an independent family - 'Krameriaceae' to a treatment proposed by Kunz (1913) on the basis of his anatomical and exomorphic studies. Benson (1970) treated Leguminosae as a family that included four sub-families Mimosoidae, Caesalpiniodae, Kramerioideae and Papilinoideae. Economically the family is of highest value among the flowering plants. It provides many articles of food, fodder, dyes, gums, resins, oils, etc. (Bois, 1927-1937; Robbins, 1936; Hill, 1937; Holland, 1937). In addition to ..this over hundred and forty genera are grown as an orna­ mental plants. In this respect the Leguminaceous plants stand second to Gramineae in value to mankind. The seeds rich in starch and proteins are a wide spread source of food as in peas (Pisum), Lentils (Lens ), pea nut (Arachis), yam bean (Pachyrrhizus), beans (Phaseolus, Dolichous), cowpeas (/igna), velvet beans (Stizolobium) and soybean (Glycine), gram (Gicer), Ga.janus, Lathyrus. The pod of Ceratonia. Tamarindus, Phaseolus, Prosopis etc., are also eaten. Fodder and forage plants such as clover (Trifolium), alfalfa (Medicago), soybean (Glycine ), lupin (Lupinus ), vetch (Vic ia), bird's-foot trefoil (Lotus) and sweet clover (i^lelilotus), Cyamopsis psoralioides, Prosopis spicigera etc., are used as fodder. Many of the trees such as Dalbergia sissoo, iJ. lati folia, iJ. nigra, IJ. retusa, Albizia lebbeck, Pterocarpus marsupium, Ougeinia dalbergioides, Xylia dolabriformis and species of Acacia, Hymenaea, Melanoxylon, Sophera furnish valuable wood. Species of Grotalaria, Sesbania yield important fibres. Numerous species of Acacia and Astragalus produce gums of commerce. Resins and balasam.s are the products obtained from the species, of Gopaifera, Hymenea and few others. "Kath" or "catechu" is obtained from Acacia catechu. The seeds of Adenanthera

and Abrus precatorius are used as means of weight. Dyes red dye from Mucuna and Caesalpinia sappan respectively, while Haematoxylon campechianum yields Maeraatoxylens. The pods of Caesalpinia coriaria yield valuable tannin materials. Species of Trifolium, Lupinus and Pisum etc., form a valuable green manure, enriching the soil in nitrogen fixation through their root nodules. Oils of different types are extracted from different members such as the ground nut oil - Arachis hypogaea an oil extensively used in cooking and form the manufacture of vegetable ^hee. Pongan oil is extracted from the seeds of Pongamia pinnata, used for illumination. An essential oil is obtained from the flowers of Acacia farnesiana. The dried leaves of Cassia form the C. acutifolia, Italian senna from _C. o bo vat a, Arabian from _C. angustifolia. Other medicinal plants are the species of Acacia, Astragalus, Tamarindus, Glycyrrhiza, Physostigma venenosum, Alhagi maurorum, Butea monosperma, Bauhinia variegata, Psoralea corylifolia, Caesalpinia crista and Saraca indiea.

Plants of ornamental value includes Cersis siliquastrum, species of VJisteria, Bauhinia, Gleditsia, Gytisus, Robinia, Delonix, Butea, Cassia, Lathyrus, Lupinus, Peltophorum, Saraca indica and Gliricidia maculata etc. The origin and distribution of the Leguminosae was studied in much detail by Andrews (I9I4 ) and is reviewed later on by Norris (1956). It is believed that the family originated in the Cretaceous Period. Members of Miraosoid and Caesalpiniod type of less specialised tropical parts recorded from ^Uppe.r Cretaceous. Papilione types were recorded from early Eocene and Oligocene (Berry, 1937i Bachofen-Echt, 1949). Andrews (1914 ) suggested that the early legumes originated in tropical regions at the end of the Cretaceous period; when the land masses of the Asian and African Continents were becoming separated. This caused separate lines of development. The early legumes, there­ fore, lived in conditions resembling present day tropical rain forests. This agrees with Corner's (1949) views on the nature of the primitive seed. k From India the first report of the occurrence of Leguminous plant was described by Carter (1954), who reported the presence of leaflets and fruits resembling to Acacia, Cassia and Hedysareae from Deccan Intertrappean beds at Bombay. Prakash (1963) discovered the wood of Aeschynomene tertiara from Mahuzari near Nagpur. The records of the various localities of different series from India. They are: Acacioxylon indicum (Ramanu.iam, 1954, Cuddalore Series, Pondicherry); A. bharadwa.li (%vale, 1963a, Cuddalore Series, Pondicherry); Cassioxylon barooahii (Prakash, 1966a, Tipam Series, Assam); C_. variegatum (Ramanujara, I960, Cuddalore Series, Pondicherry); Peltophoroxylon cassioides (Prakash and Awasthi, 1970, Tipam Series, Assam); Aeschynomene tertiara (Prakash, 1963, Deccan Intertrappeans, Mahuzari, Nagpur); Cynometroxylon indicum (Chowdhury ana Ghosh, 1946; Prakash, 1966a; Ramanujam and Rao, 1966a, Tipam Series, liii, and G. dakshinense (Navale, 1959, Cuddalore Series, Pondicherry); Adenantheroxy1on indicum (Prakash and Tripathi, 1969a, Tipam Series, Assam); Millettioxylon indicum (Awasthi, 1967, Cuddalore Series, Pondicherry); Albizioxylon sahni (Ramanu­ jam, I960, Cuddalore Series, Pondicherry); Tamarindoxylon antiquum (Ramanujam, 1961, Cuddalore Series, South Arcot, Madras); Pterocarpoxylon arcotense (Ramanujam, I960, Cuddalore Series, Pondicherry); Caesalpinioxylon sitholeyi (Ramanujam, 1954, Cuddalore Series, Pondicherry); Q_. feistmantali (Ramanujam, I960, Cuddalore Series, Pondicherry); C.felixii (Navale, 1963a, Cuddalore Series, Pondicherry); Pahudioxylon deomaliense (Prakash, 1965, Tipam Series, Assam); P. sahnii (Prakash, 1966b, Tipam Series, Assam); £. bankurensis (Chowdhury, Ghose and Kazmi, I960, West Bengal); £. arcotense (Navale, 1963a, Cuddalore Series, Pondicheri-y); Dalbergia sissoq (Lakhanpal and Dayal, 1966, Siwaliks, Jwalaraukhi, Himachal Pradesh); Dalber^ioxylon antiquum (Ramanujam, I960, Cuddalore Series, Pondicherry); and 3auhnioxylon indicum (Rawat, 1964-1965, Siwaliks, Mohand near Saharanpur, U.P.). There is a story about the presentation and distri­ bution of the leaves of Bauhinia amongst the people on the occasion of uesera festival (that is Vijayaaashmi). In evening at the time of Shilangan, Gold is presented in terms of leaves of Bauhinia. The story reaas as follows^

Once there was a king by name Raghu, who won all the earth. He performed a Yagna, collecting lot of wealth. He distributed the wealth amongst the poorer^ and asked his son to take over the kingship. He went to forest for meditation, where he spent his most of the time in the meditation of God. Once a brilliant youth came to his cottage, wnose name was Koutsa. He was disciple of Saint v'aratantu. After completing his studies, he expressed his desire to offer Gurudakkshina. Guru told him not to give him anything but to make good use of his studies for the sake of good things. But Koutsa did not agree for the same. Hence, Guru became very much annoyea and told him to give him I40 million Gold coins.

Poor Koutsa could not have that much money with him. He had heard the name of King Raghu, whom he requested to help. Raghura,1a told him that he had already distributed his wealth, but now he will invade the Swarga (Heaven) and give him the required money. Lord Indra came to know aoout this. He showered infinite amount of gold coins from Heaven. Raghuraja has given all those coins to ivoutsa, but Koutsa took only the required amount and gave it to his Guru. This has happened on the Uasera day. Golden coins have fallen on the tree of Bauhinia. Therefore, the leaves of Bauhinia are called as Gold ana are distributed as a token of the above incident to show the bravery and the effect of meditation. from the above discussion, it is clear that the opinion is divided aoout the status of Gaesalpiniaceae. Some Botanists consider Caesalpiniaceae as the most primi­ tive family in the Leguminosae, others include it in Papilionaceae as its sub-family. Hence, it was thought worthwhile to study the members of Caesalpiniaceae. With this view the genus Bauhinia L. in particular was selected in continuation with the other genera like Cassia, Hardwickia, etc., being investigated by other workers in the Department of Botany, University of Poona, under Dr. N. V. Biradar.