Legumes ( Angiosperms : Fabaceae ) of Bagalkot District , Karnataka , India

Fabaceae Lindl. or Leguminosae is one of the largest families of Angiosperms. Due to adaptability in various climatic conditions, members of the family Fabaceae are worldwide in their distribution. Globally, Fabaceae is represented by 770 genera and 19,500 taxa. Bagalkot is one of the largest districts of northern Karnataka and falls under the Deccan Peninsular region of India. The study area (Bagalkot District) is a rain shadow region and remains dry and hot throughout year. During floristic analysis of the District the authors recorded 157 species of legumes, which is communicated here in relation to habitat, life forms, distribution, classification and their importance.


INTRODUCTION
Legumes are the third largest group of Angiosperms in terms of species number after Orchidaceae and Asteraceae and the second economically most important family after Poaceae (FAO 2016). Globally Fabaceae consists of 770 genera and over 19,500 species (LPWG 2017) in India, Fabaceae are represented by 147 genera, 805 species, 33 sub-species, 155 varieties and 14 forms (Sanjappa 1991(Sanjappa , 1995Dave 2004;Chaudhary & Khan 2005;Ansari 2008;Jabbar et al. 2010;Chavan et al. 2013;Gaikwad et al. 2014). Legumes are important food crops providing highly nutritious sources of protein and micronutrients. These micronutrients greatly benefit health and livelihoods, particularly in developing countries. They have been domesticated alongside grasses in different areas of the world since the beginning of agriculture and have played a key role in early agricultural development (Gepts et al. 2005;Hancock 2012;Yahara et al. 2013). Wild bean plants are also uniquely important as fodder and green manure in both temperate and tropical regions, and are used for their wood, tannins, oils and resins, in the manufacture of varnishes, paints, dyes and medicines and in the horticultural trading (LPWG 2017). Apart from socio-economic importance, legumes are equally beneficial for ecosystems and recycling by nitrogen fixation, improve soil porosity and structure, recycling of nutrients, decrease soil pH, reduction of soil compaction and in rotation with cereals they provide a source of slow-release nitrogen to sustainable cropping system (USDA 1998;Popelka et al. 2004). Many legumes play an important ecological role as they are major components of dry deciduous forests, ground cover and many are cultivated as major crops of the region and some have ornamental potential. In brief, legumes play a major role in socio-economic development of the region. Therefore, the present study focuses on the preparation of the database of legumes of Bagalkot District. While surveying this area it is observed that the flora of this district is dominated by the family Fabaceae. The probable reason of this high diversity may be adaptability to various habitats.

Study area
Bagalkot is a district of northern Karnataka State separated from Vijayapura in 1997. The whole region falls under the Deccan Plateau and most of it comes under a rain shadow area. Due to low rainfall and hot & dry climatic conditions, the region is dominated by dry deciduous forests, scrub jungles, and vast seasonal grasslands. The district lies at 16.316 0 N, 76.000 0 E and 533m altitude and having a total area of 6,552km 2 (Dalavi et al. 2019). The district is divided into six sub-district regions, namely: Badami, Bagalkot, Bilgi, Hungund, Jamkhandi and Mudhol (Fig. 1). Rabakavi-Banahatti Guledgudda and Ilkal are newly divided taluk places. Major habitats of the districts are large rocky hills, gravelly slopes, sandy plains, perennial & seasonal lakes, marshy & saline areas, ditches, rivers, and black soil plains. Average rainfall recorded in the last decade ranges 337-819 mm and the average temperature reported ranges 17-42 0 C. June to September is the monsoon season and February to May is the actual summer season. Due to hot arid conditions the area is blessed with spiny and thorny forests interrupted with grasslands.
Herbarium studies were carried out by visiting some important herbaria namely BSI, CAL, MH, NGCPR and SUK, which was followed by extensive and intensive field tours throughout the district covering various habitats from June 2014 to January 2020. More than 90 tours were carried out and the data on habitat, distribution, phenology and local uses were recorded. Three to four herbarium specimens were prepared for each collected species by following standard procedures (Rao & Sharma 1990). Identifications were confirmed by using floras, revisions and all the available taxonomic literature (Gamble 1935;Cooke 1958;Matthew 1981;Sharma et al. 1984;Sharma & Balakrishnan 1993;Prasad & Singh 2002;Kanbhar & Katrahalli 2016). Problematic and notable species were identified by direct comparison with identified specimens deposited in BSI, SUK, CAL and digital herbaria such as Herbarium JCB (accessed from January 2014-December 2019), Kew Herbarium Catalogue (accessed from January 2017-March 2020) and JSTOR Global Plants (accessed from February 2017-December 2019). The nomenclature of plant species collected was updated using POWO (Plants of the world online Kew-science accessed from January 2015-December 2019) and Tropicos (tropicos.org accessed J TT from January 2017-January 2020). All leguminous taxa are grouped here according to the latest classification of Fabaceae (LPWG 2017) (Table 1). Charts and maps are provided for subfamily-wise classification and study area, respectively. Colour plates for important taxa are also provided for easy identification of species. Ethnobotanical information was collected by direct interaction with local people, ayurvedic practitioners and farmers.

Enumeration
A total of 157 taxa of Fabaceae have been reported from the Bagalkot District of Karnataka which measures about 15% of the total flora. All the legumes of the district belong to four subfamilies of Fabaceae, viz., Cercidoideae, Detarioideae, Caesalpinioideae and Papilionoideae; of which Papilionoideae or Faboideae is the largest subfamily with 45 genera and 106 species followed by Caesalpinioideae with 22 genera & 45 species, Cercidoideae with three genera & four species and Deratioideae with two genera & two species, respectively (Fig. 2). Crotalaria L. and Indigofera L. are the largest genera with 12 species each, followed by Rhynchosia Lour. with 10 taxa and Alysicarpus Desv. & Senna L. with nine species each. Fabaceae of the district consists of 48 tree species, eight shrubs, eight subshrubs, 74 herbs, and 18 climbers & creepers.

Endemism
Some plants are habitat specific and are endemic to peninsular India, viz., Alysicarpus gamblei Schindl., Crotalaria paniculata Willd., C. pusilla Roxb. ex Wight & Arn., C. vestita Baker found to be growing on rocky and sandy areas and are endemic to southern peninsular India (Dalavi et al. 2019). Alysicarpus gamblei Schindl. is only known from six localities of Karnataka and Maharashtra of which Bagalkot District has the highest population (Dalavi et al. 2019). Vigna indica Dixit et al. is also a dominant species of open areas and grasslands endemic to peninsular India. Mimosa prainiana Gamble a woody tree endemic to peninsular India which is also important member of dry forests of Bagalkot District.

Ethnobotany and economics
Many wild legumes are used as a source of medicine and food by local people. Pods of Vachellia nilotica (L.) P.J.H.Hurter & Mabb. are used to make tooth powder by drying and crushing the seeds; gum exuded from the stem is highly valued and used to cure many diseases and is edible, generally given to pregnant ladies in the form of small pieces mixed with dry fruits; tender branches are used as fodder for goats, timber is used in building and construction. Fresh flowers of Sesbania grandiflora

Ecology
Apart from the economic potential, some legumes are dominant weeds of the region like Aeschynomene aspera L., A. indica Burm.f., Neptunia triquetra Benth., etc., which grow along water bodies and spread throughout. N. triquetra if it enters into a pond ecosystem grows aggressively and forms a dense mat on the water surface and affects other biota. Legumes play some important ecological roles. They are the factories of nitrogen fixation being equipped with root nodules. The study area is an arid zone hence it lacks dense forests. The resulting soil erosion is due to minimum leaf litter which fails to keeps soil moisture constant, however, some legumes, viz., Crotalaria hebecarpa (DC.) Rudd., C. orixensis Rottler ex Willd.,    www.threatenedtaxa.org The Journal of Threatened Taxa (JoTT) is dedicated to building evidence for conservation globally by publishing peer-reviewed articles online every month at a reasonably rapid rate at www.threatenedtaxa.org. All articles published in JoTT are registered under Creative Commons Attribution 4.0 International License unless otherwise mentioned. JoTT allows allows unrestricted use, reproduction, and distribution of articles in any medium by providing adequate credit to the author(s) and the source of publication.

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