International Journal of Research in Pharmacy and Biosciences Volume 3, Issue 3, March 2016, PP 1-10 ISSN 2394-5885 (Print) & ISSN 2394-5893 (Online)

Vascular Wall Flora of Varanasi City, : An Update

Arvind Singh Department of Botany, Banaras Hindu University, Varanasi-221 005, India

ABSTRACT An observational study was conducted to update the vascular wall flora of the world’s oldest city of Varanasi, which spreads over an area of about 150 km2 and situated on the bank of sacred River in Uttar Pradesh state of India. A total of 192 vascular species were recorded from the walls of city, of which 190 species were represented by angiosperms belonging to 147 genera and 51 families while only 2 species were represented by the pteridophytes belonging to 2 genera and 2 families. No any species of gymnosperms was recorded from the walls of Varanasi city. Asteraceae, and were the dominant families of the vascular wall flora of Varanasi city. Analysis of wall flora with respect to life forms indicated the dominance of therophytes. The exotic plant species exceeds the number of native plant species on the walls of Varanasi city. benghalensis, Ficus racemosa, Ficus religiosa, Lindenbergia indica and Tridax procumbens were the most common species observed on the walls of Varanasi city. Keywords: Exotic species, native species, Uttar Pradesh, Varanasi city, vascular wall flora

INTRODUCTION Varanasi popularly known as Kashi, Benares or Banaras is located in the eastern region of Uttar Pradesh state in Northern India. This city exists between the rivers Varuna and Asi, the two tributaries of the holy river Ganges (also known as Ganga) from which it derives its name Varanasi. It is the cultural capital of India and has long continuous history since 1500 B.C. and finds a mention in the Veda and Purana [1]. Thus Varanasi is the most ancient living city of the world. Varanasi has also been a very important center of learning from ancient times. The city hosts four universities including Banaras Hindu University which is the largest teaching and residential university of . Walls are human-made habitats representing a specific environment which is partly similar to rocks and rock fissures [2]. The artificial origin of walls, their location in urban landscape and technology of their building influences a range of plant species which are able to colonize such habitats [3]. As a specialized microenvironment conditioned by human beings, walls are colonized only by plant species with specific adaptations for development and reproduction [4, 5]. Considering vertical division, walls usually consist of three different zones (i) the base, (ii) the vertical wall surface with joints (fissures); and (iii) the wall top [3]. The colonization of on walls is favoured by the age of walls, presence of lime mortar and exposure to rain [6]. According to Gilbert (1991) [7] most true wall species are only found on vertical walls and as the angle of inclination decreases an ever-widening range of common species colonize. Plants growing on the walls reach these habitats by wind, birds and animals and by stolon fragments [3, 8] and grow there randomly [6]. The study of wall flora provides a better understanding of the urban environment [2, 9-11]. Various studies have been conducted to explore the wall flora in urban environment [2, 3, 6, 9-18]. Varshney (1971) [19] was the first to study the wall flora of Varanasi. Thereafter Singh (2014) [20] has attempted to investigate the vascular wall flora of this old city. The present study was undertaken with main objective to update the vascular wall flora of Varanasi city which is the most ancient among the extant cities of the world. The questions addressed in the study were: (i) how many species of vascular plants are hosted by the walls of Varanasi city? (ii) which families dominate the wall flora of the city? (iii) vascular wall plants of which origin status dominate the wall flora of Varanasi city?; and (iv) vascular plant species of which life forms dominate the wall flora of Varanasi city?

*Address for correspondence [email protected] International Journal of Research in Pharmacy and Biosciences V3● I3● March 2016 1 Arvind Singh “Vascular Wall Flora of Varanasi City, India: An Update” STUDY AREA Varanasi is situated on the left crescent bank of sacred river Ganges (Fig. 1). It lies 25o 18’ north latitude and 82o 59’ east longitude and stands a height between 71-80 m above mean sea level. The city spreads over an area of about 150 km2 with population of about 1.4 million according to 2011 census.

Figure1. Map of the study area

Figure2. Ficus benghalensis growing on vertical surface of an older wall near Asi Ghat of Varanasi city

2 International Journal of Research in Pharmacy and Biosciences V3 ● I3 ● March 2016 Arvind Singh “Vascular Wall Flora of Varanasi City, India: An Update” The soil is alluvial type formed by the deposition of sediments of Ganges River. Being located in the Indo-Gangetic Plains of North India the soil is very fertile as the low level floods continuously replenish the soil. Moreover, the soil is sandy loam in texture. The climate is Tropical monsoonal type with three distinct seasons; the cold (November to February), the hot (March ˗ mid-June), and the rainy (mid-June ˗September) while October is regarded strictly as transitional month. The diurnal range of temperature ranges on average between 13 and 14.5o C in the cold and hot months. The highest monthly temperature is recorded in May, varying between 32 and 42oC. The annual rainfall is around 1000 mm of which about 90% occurs in the rainy season [21]. The Varanasi district is rich in floral diversity dominated by the Fabaceae, Asteraceae and Poaceae families [22]. METHODOLOGY The present study is based on a yearlong intensive field survey and collection taken from July 2014 to June 2015. The entire city was divided into four zones i.e. north, south, east and west. One weekly field visit was made in each zone of the city in a month (i.e. 12 field visits in each zone in a year). Thus a total of 48 visits were made in one year in city in the hunt of vascular wall plants. During the field visit all attempts were made to cover the each and every corner of the city. The walls were thoroughly observed from the base to the top to record the plant species. The recorded vascular wall plants were collected from the field for identification. Plants growing on much height on vertical wall surfaces and the wall tops were collected by climbing with the help of ladder. The walls surveyed to record and collect the plants included older walls surrounding residential compounds, parks, gardens, schools, colleges, universities, hospitals, temples, forts, monuments etc., and also the walls of all types of buildings, temples, forts and monuments as well. The collected specimens were identified through various sources [23-25]. The APG III (2009) [26] classification was followed for arranging the taxa to families. RESULTS AND DISCUSSION A total of 192 vascular plant species were recorded from the walls of Varanasi city, of which 190 plant species were represented by the angiosperms while only 2 species were represented by the pteridophytes (Table 1). Compared to the result of the present study Varshney (1971) [19] has recorded 136 vascular plant species from the walls of Varanasi of which 135 species were represented by angiosperms while only one species was represented by the pteridophytes. Another previous study on wall flora of the city of Varanasi reports 173 plant species, of which 171 plant species were represented by angiosperms and only two by the pteridophytes [20]. Studies on the wall flora of European cities reports 174 to 385 plant species [27, 28]. Furthermore, Dos Reis et al. (2006) [16] have recorded only 28 plant species from the walls of a Brazilian city. In the present study no any species of the gymnosperms was recorded from the walls of Varanasi city. Thus the vascular wall flora of Varanasi city is dominated by the angiospermic group of plants. The angiosperms were represented by 147 genera belonging to 51 families. Of the total recorded angiospermic plants, 160 plant species were represented by dicotyledons belonging to 123 genera and 48 families whereas the were represented by 30 plant species belonging to 24 genera and 3 families (Table 2). Thus it is evident from the study that the dicotyledonous plant species dominate the vascular wall flora of Varanasi city with greater degree of variety compared to monocotyledonous species. Majority of the species recorded in the study are weeds of agro-ecosystems and ruderal plants [22]. Weeds of agricultural fields and ruderal plants are the chief constituents of the wall flora [16, 28]. Table1. List of vascular plants recorded from the walls of Varanasi city S. No. Family/Plant species Habit Origin status Life forms ANGIOSPERMS Dicotyledons Acanthaceae 1. Blepharis boerhaviaefolia Pers. Herb Native Therophyte 2. Elytraria acaulis (L. f.) Lindau Herb Exotic Therophyte 3. Justicia diffusa Willd. Herb Exotic Therophyte 4. Justicia simplex D. Don Herb Exotic Therophyte 5. Peristrophe bicalyculata (Retz.) Nees Herb Native Therophyte 6. Ruellia tuberosa L. Herb Exotic Therophyte

International Journal of Research in Pharmacy and Biosciences V3● I3● March 2016 3 Arvind Singh “Vascular Wall Flora of Varanasi City, India: An Update” 7. Rungia pectinata (L.) Nees Herb Native Therophyte 8. Rungia repens (L.) Nees Herb Native Therophyte Aizoaceae 1. Trianthema portulacastrum L. Herb Native Therophyte Amaranthaceae 1. Achyranthes aspera L. Herb Native Therophyte 2. Aerva lanata (L.) Juss. ex Schult. Herb Native Chamaephyte 3. Alternanthera sessilis R. Br. Herb Exotic Chamaephyte 4. Amaranthus polygamosus L. Herb Native Therophyte 5. Amaranthus spinosus L. Herb Exotic Therophyte 6. Amaranthus tenuifolius Willd. Herb Exotic Therophyte 7. Amaranthus viridis L. Herb Native Therophyte 8. Celosia argentea L. Herb Native Therophyte 9. Chenopodium album L. Herb Exotic Therophyte 10. Digera arvensis Forssk. Herb Native Therophyte Annonaceae 1. Anona squamosa L. Shrub Exotic Phanerophyte Apiaceae 1. Centella asiatica (L.) Urban Herb Native Hemicryptophyte Apocynaceae 1. Alstonia scholaris R. Br. Native Phanerophyte 2. Catharanthus roseus G. Don Herb Exotic Therophyte 3. (L.) R. Br. Shrub Native Phanerophyte 4. Calotropis procera (Ait.) R. Br. Shrub Native Phanerophyte 5. Thevetia peruviana Schum Shrub Exotic Phanerophyte Asteraceae 1. Acmella oleracea (L.) R. K. Janson Herb Exotic Therophyte 2. Ageratum conyzoides L. Herb Exotic Therophyte 3. Bidens biternata (Lour.) Merr. & Scherff Herb Exotic Therophyte 4. Blumea aromatica DC. Herb Native Therophyte 5. Blumea eriantha DC. Herb Native Therophyte 6. Blumea indica L. Herb Native Therophyte 7. Blumea lacera DC. Herb Native Therophyte 8. Blumea oxyodonta DC. Herb Native Therophyte 9. Echinops echinatus Roxb. Herb Native Therophyte 10. Eclipta alba Hassk Herb Native Therophyte 11. Gnaphalium indicum L. Herb Exotic Therophyte 12. Gnaphalium purpureum L. Herb Exotic Therophyte 13. Launaea procumbens (Roxb.) Ramayya & Rajagopal Herb Native Therophyte 14. Parthenium hysterophorus L. Herb Exotic Therophyte 15. Sonchus arvensis L. Herb Exotic Therophyte 16. Sonchus oleraceus L. Herb Exotic Therophyte 17. Sphaeranthus indicus L. Herb Exotic Therophyte 18. Tagetes erecta L. Herb Exotic Therophyte 19. Tagetes patula L. Herb Exotic Therophyte 20. Taraxacum officinale Webb. Herb Exotic Therophyte 21. Tridax procumbens L. Herb Exotic Therophyte 22. Vernonia cinerea (L.) Less. Herb Native Therophyte 23. Xanthium strumarium L. Herb Native Therophyte Balsaminaceae 1. Impatiens balsamina L. Herb Native Therophyte Bignoniaceae 1. Tecoma stans (L.) H. B. & K Tree Exotic Phanerophyte Boraginaceae 1. Heliotropium indicum L. Herb Exotic Chamaephyte 2. Heliotropium strigosum Willd. Herb Exotic Chamaephyte Brassicaceae 1. Brassica rapa L. Herb Exotic Therophyte Cannabaceae 1. Cannabis sativa L. Herb Exotic Therophyte Caricaceae

4 International Journal of Research in Pharmacy and Biosciences V3 ● I3 ● March 2016 Arvind Singh “Vascular Wall Flora of Varanasi City, India: An Update” 1. Carica papaya L. Herb Exotic Phanerophyte Cleomaceae 1. Cleome viscosa L. Herb Native Therophyte Convolvulaceae 1. Convolvulus arvensis L. Herb Exotic Chamaephyte 2. Convolvulus pluricaulis L. Herb Native Chamaephyte 3. Evolvulus nummularius L. Herb Native Chamaephyte Cucurbitaceae 1. Citrullus lanatus (Thunb.) Matsum. & Nakai Herb Exotic Therophyte 2. Coccinia grandis (L.) Voigt. Herb Native Therophyte 3. Luffa acutangula (L.) Roxb. Herb Native Therophyte 4. Luffa cylindrica (L.) Roem. Herb Exotic Therophyte 5. Momordica charantia L. Herb Native Therophyte 1. ciliata Forsk. Herb Exotic Therophyte 2. Acalypha indica L. Herb Native Therophyte 3. Chrozophora rottleri Juss. Herb Native Therophyte 4. Croton bonplandianum Baill. Herb Exotic Therophyte 5. Euphorbia hirta L. Herb Exotic Therophyte 6. Euphorbia thymifolia L. Herb Exotic Therophyte 7. Jatropha integerimma Jacq. Shrub Exotic Phanerophyte 8. Ricinus communis L. Shrub Exotic Phanerophyte Fabaceae 1. Albizia lebbeck (L.) Willd. Tree Native Phanerophyte 2. Calliandra haematocephala Hassk Shrub Exotic Phanerophyte 3. Dalbergia sissoo Roxb. Tree Native Phanerophyte 4. Dichrostachys cinera (L.) Wt. & Arn. Shrub Native Phanerophyte 5. Lablab purpureus (L.) Sweet Herb Exotic Phanerophyte 6. Lathyrus aphaca L. Herb Native Therophyte 7. Leucaena leucocephala Willd. Tree Exotic Phanerophyte 8. albus Medik. Herb Exotic Chamaephyte 9. Melilotus indicus (L.) All. Herb Native Chamaephyte 10. Mimosa pudica L. Herb Exotic Chamaephyte 11. Senegalia polycantha (Willd.) Seigler & Ebiner Shrub Native Phanerophyte 12. Senna alata (L.) Roxb. Shrub Exotic Phanerophyte 13. Senna occidentalis (L.) Link. Shrub Exotic Phanerophyte 14. Senna tora (L.) Roxb. Herb Exotic Therophyte 15. Sesbania sesban (L.) Merr. Shrub Exotic Phanerophyte 16. Trifolium alexandrium L. Herb Exotic Phanerophyte 17. Vachellia nilotica (L.) P.J.H Hurter & Mabb. Tree Exotic Phanerophyte Lamiaceae 1. Hyptis suaveolens (L.) Poir. Herb Native Therophyte 2. Nepeta ruderalis Buch. – Ham. ex Benth. Herb Exotic Therophyte 3. Ocimum canum Sims. Herb Exotic Therophyte 4. Ocimum sanctum L. Shrub Native Therophyte 5. Salvia plebeia R. Br. Herb Exotic Therophyte Linderniaceae 1. Lindernia ciliata (Colsm.) Pennell Herb Exotic Therophyte 2. Lindernia crustacea (L.) F. Muell Herb Native Therophyte Lythraceae 1. Lawsonia inermis L. Shrub Exotic Phanerophyte 2. Punica granatum L. Shrub Exotic Phanerophyte Malvaceae 1. Abutilon indicum (L.) Sweet Shrub Native Phanerophyte 2. Bombax ceiba L. Tree Native Phanerophyte 3. Corchorus acutangulus Lamk. Herb Exotic Therophyte 4. Hibiscus syriacus L. Shrub Exotic Phanerophyte 5. Malvastrum tricuspidatum L. Undershrub Exotic Therophyte 6. Sida acuta Burm. f. Undershrub Exotic Therophyte 7. Sida cordifolia L. Undershrub Native Therophyte 8. Sida rhombifolia L. Undershrub Exotic Therophyte

International Journal of Research in Pharmacy and Biosciences V3● I3● March 2016 5 Arvind Singh “Vascular Wall Flora of Varanasi City, India: An Update” 9. Urena lobata L. Undershrub Exotic Therophyte Martyniaceae 1. Martynia annua L. Herb Exotic Therophyte Meliaceae 1. Azadirachta indica A. Juss. Tree Native Phanerophyte 2. Melia azedarach L. Tree Native Phanerophyte 1. Ficus benghalensis L. Tree Native Phanerophyte 2. Ficus hispida L. f. Tree Native Phanerophyte 3. Ficus mollis Vahl Tree Native Phanerophyte 4. Ficus racemosa L. Tree Exotic Phanerophyte 5. Ficus religiosa L. Tree Native Phanerophyte 6. Ficus virens var. sublanceolata Miq. Corner Tree Native Phanerophyte 7. Morus alba L. Tree Exotic Phanerophyte Moringaceae 1. Moringa oleifera Lam. Tree Native Phanerophyte Myrtaceae 1. Psidium guajava L. Tree Exotic Phanerophyte Nyctaginaceae 1. Boerhavia diffusa L. Herb Native Chamaephyte Oleaceae 1. Nyctanthes arbor-tristis L. Shrub Native Phanerophyte Orobanchaceae 1. Lindenbergia indica (L.) Kuntz Herb Native Therophyte Oxalidaceae 1. Biophytum sensitivum DC. Herb Native Therophyte 2. Oxalis corniculata L. Herb Exotic Chamaephyte Papavaraceae 1. Argemone mexicana L. Herb Exotic Therophyte Pedaliaceae 1. Sesamum indicum L. Herb Exotic Therophyte Phyllanthaceae 1. Phyllanthus fraternus Webst. Herb Native Therophyte Piperaceae 1. Peperomia pellucida (L.) Kunth. Herb Exotic Therophyte Plantaginaceae 1. Kickxia ramosissima (Wall.) Janch. Herb Exotic Therophyte 2. Scoparia dulcis L. Herb Native Therophyte Polygonaceae 1. Rumex dentatus L. Herb Native Therophyte Portulacaceae 1. Portulaca oleracea L. Herb Exotic Chamaephyte 2. Portulaca quadrifida L. Herb Exotic Therophyte 3. Portulaca grandiflora Hook. Herb Exotic Therophyte Primulaceae 1. Anagallis arvensis L. Herb Exotic Therophyte Rhamnaceae 1. Ziziphus nummularia (Burm. f.) Wt. & Arn. Shrub Native Phanerophyte 2. Ziziphus oenoplia Mill. Shrub Native Phanerophyte Rubiaceae 1. Borreria articularis L. Herb Native Therophyte 2. Oldenlandia corymbosa L. Herb Native Therophyte 3. Oldenlandia dichotoma Hook. Herb Native Therophyte 4. Oldenlandia diffusa Roxb. Herb Native Therophyte Rutaceae 1. Aegle marmelos (L.) Corr. Tree Native Phanerophyte 2. Murraya paniculata (L.) Jacq. Shrub Native Phanerophyte Scrophulariaceae 1. Verbascum chinense (L.) Staut. Herb Exotic Therophyte Solanaceae 1. Capsicum annuum L. Undershrub Exotic Phanerophyte

6 International Journal of Research in Pharmacy and Biosciences V3 ● I3 ● March 2016 Arvind Singh “Vascular Wall Flora of Varanasi City, India: An Update” 2. Cestrum nocturnum L. Shrub Native Phanerophyte 3. Datura innoxia Mill. Shrub Exotic Phanerophyte 4. Datura metel L. Undershrub Exotic Phanerophyte 5. Datura stramonium L. Herb Exotic Therophyte 6. Nicotiana plumbaginifolia Viv. Herb Exotic Therophyte 7. Physalis minima L. Herb Exotic Therophyte 8. Petunia hybrida Vilm. Herb Exotic Therophyte 9. Solanum nigrum L. Herb Native Therophyte 10. Solanum virginianum L. Herb Native Therophyte Ulmaceae 1. Holoptelea integrifolia (Roxb.) Planch. Tree Exotic Phanerophyte Urticaceae 1. Urtica dioica Roxb. Herb Native Hemicryptophyte Verbenaceae 1. Lantana camara L. Shrub Exotic Phanerophyte 2. Phyla nodiflora (L.) Greene Herb Exotic Chamaephyte Vitaceae 1. Cayratia trifolia (L.) Domin Herb Native Phanerophyte Monocotyledons Commelinaceae 1. Aneilema nudiflorum R. Br. Herb Native Therophyte 2. Commelina benghalensis L. Herb Native Therophyte 3. Commelina diffusa Burm. Herb Native Therophyte 4. Cyanotis axillaris Schult. Herb Native Therophyte Cyperaceae 1. Cyperus compressus L. Herb Native Therophyte 2. Cyperus difformis L. Herb Native Therophyte 3. Cyperus iria L. Herb Native Therophyte 4. Kyllinga triceps Rottb. Herb Exotic Therophyte Poaceae 1. Apluda mutica var. aristata (L.) Hack. ex Backer Herb Native Therophyte 2. Brachiaria ramosa (L.) Stapf Herb Exotic Therophyte 3. Chloris incompleta Roth. Herb Exotic Therophyte 4. Chloris virgata Swartz Herb Exotic Hemicryptophyte 5. Cynodon dactylon (L.) Pers. Herb Exotic Hemicryptophyte 6. Dactyloctenium aegyptium Beauv. Herb Native Hemicryptophyte 7. Dichanthium annulatum (L.) Stapf Herb Native Cryptophyte 8. Digitaria marginata Beauv. Herb Native Therophyte 9. Digitaria sanguinalis (L.) Scop. Herb Native Therophyte 10. Echinochloa colonum (L.) Link Herb Native Therophyte 11. Eleusine indica (L.) Gaertn. Herb Native Chamaephyte 12. Elymus repens (L.) Gould Herb Native Therophyte 13. Eragrostis amabillis (L.) Wt. & Arn. ex Nees Herb Exotic Therophyte 14. Eragrostis viscosa Trin. Herb Native Therophyte 15. binata (Retz.) C. E. Hubbard Herb Native Therophyte 16. burmannii Beauv. Herb Exotic Chamaephyte 17. Panicum psilopodium Trin. Herb Native Therophyte 18. Phalaris minor Retz. Herb Native Therophyte 19. Poa annua L. Herb Exotic Therophyte 20. Saccharum munja Roxb. Herb Native Cryptophyte 21. Setaria viridis (L.) P. Beauv. Herb Exotic Therophyte 22. Sporobolus diander Beauv. Herb Exotic Cryptophyte PTERIDOPHYTES Dryopteridaceae 1. Dryopteris filix-mas (L.) Schott Herb Native Cryptophyte Pteridaceae 1. Pteris vittata L. Herb Exotic Cryptophyte Study on the family wise representation by vascular plant species growing on the walls of Varanasi city reveals that Asteraceae is the largest family represented by 23 plant species followed by Poaceae and Fabaceae families represented by 22 and 17 plant species, respectively Therefore, the study

International Journal of Research in Pharmacy and Biosciences V3● I3● March 2016 7 Arvind Singh “Vascular Wall Flora of Varanasi City, India: An Update” suggests that the Asteraceae, Poaceae and Fabaceae are the dominant families of the vascular wall flora of Varanasi city. A previous study on the wall flora of the Varanasi city also reports the dominance of Asteraceae, Poaceae and Fabaceae families [20]. Wall flora study in the city of Plovdiv (Bulgaria) also has similar finding [15]. Furthermore, Singh (2011) [17] has reported Asteraceae, Poaceae and Amarantaceae as dominant families of the vascular wall flora of Banaras Hindu University main campus (Varanasi). Several studies reports Asteraceae and Poaceae as the two most dominant families of the wall flora [6, 11, 28-30]. Study on the habits of plants growing on the walls of Varanasi city reveals that, 141 (73%) were represented by the herbs, 7 (4%) by the undershrubs, 24 (13%) by the shrubs and 20 (10%) plants species were represented by the . Thus the plants of herb habit dominate the wall flora of Varanasi city. Other studies on wall flora also suggests the dominance of the plants of herb habit over the plants of other habits [11, 15-17, 28, 29]. Study on the origin status of the wall plants of Varanasi city reveals that of the total recorded species, 94 (49%) were represented by native species while 98 (51%) were represented by the exotic species. Furthermore, among angiosperms the dicotyledonous group was represented by 73 native species and 87 exotic species while the monocotyledonous group was represented by 20 native species and 10 exotic species (Table 2). Therefore the exotic species exceeds the number of native species in the wall flora of Varanasi city. Singh (2015) [22] reported the dominance of exotic species over native species in the flora of Varanasi district. Since the wall flora is influenced by the nearby ruderal and semi- natural vegetation [6], hence this may be the probable reason behind greater number of exotic species on the walls of Varanasi city. Several studies on wall flora reports that a good proportion of plants are represented by the non-native species [11, 17, 31, 32]. Table2. Analysis of species, genera, families and origin status of angiosperms in the wall flora of Varanasi city Angiospermic group Species Genera Families Origin status Native Exotic Dicotyledons 160 123 48 73 87 Monocotyledons 30 24 3 20 10 Total 190 147 51 93 97 The study of the wall flora according to Raunkiaer’s life forms system (Raunkiaer, 1934) [33] in the present study reveals the dominance of therophytes (61%) (Table 3). Varshney (1971) [19] has also reported the dominance of therophytes in the wall flora of Varanasi. However, other studies on the wall flora reports the dominance of hemicryptophytes and therophytes [3, 6, 30, 34, 35]. Table3. Per cent contribution by different Life forms in the wall flora of Varanasi city S. No Life Forms Per cent contribution 1. Phanerophytes 25 2. Chamaephytes 8 3. Hemicryptophytes 3 4. Cryptophytes 3 5. Therophytes 61 It was observed during the study that the base of the walls of Varanasi city were generally colonized by Acalypha indica, Acalypha ciliata, Ageratum conyzoides, Alternanthera sessilis, Aerva lanata, Amaranthus spinosus, Amaranthus viridis, Anagallis arvensis, Boerhavia diffusa, Brachiaria ramosa, Calotropis gigantea, Calotropis procera, Chenopodium album, Chrozophora rottleri, Commelina benghalensis, Corchorus acutangulus, Cyanodon dactylon, Cyperus compressus, Cyperus iria, Dactyloctenium aegyptium, Digitaria marginata, Digitaria sanguinalis, Digera arvensis, Datura metel, Echinochloa colonum, Eclipta alba, Euphorbia hirta, Evolvulus nummularius, Ficus hispida, Ficus religiosa, Gnaphalium indicum, Gnaphalium purpureum, Heliotropium indicum, Heliotropium strigosum, Holoptelea integrifolia, Hyptis suaveolens, Justicia diffusa, Justicia simplex, Kyllinga triceps, Launaea procumbens, Lindernia ciliata, Lindernia crustacea, Melilotus albus, Malvastrum tricuspidatum, Nicotiana plumbaginifolia, Oxalis corniculata, Oldenlandia corymbosa, Oldenlandia diffusa, Oplismenus burmanii, Parthenium hysterophorus, Phyllanthus fraternus, Rumex dentatus, Ruellia tuberosa, Rungia pectinata, Rungia repens, Scoparia dulcis, Solanum nigrum, Solanum virginianum, Senna tora, Sonchus arvensis, Sonchus oleraceus, Sporobolus diander, Scoparia dulcis, Sida acuta, Sida cordifolia, Taraxacum officinale, Trianthema portulacastrum, Tridax procumbens, Urena lobata, Urtica dioica, Vernonia cinerea and Xanthium strumarium. All these recorded plants

8 International Journal of Research in Pharmacy and Biosciences V3 ● I3 ● March 2016 Arvind Singh “Vascular Wall Flora of Varanasi City, India: An Update” growing on the basal zone of walls are the constituent species of the flora of Varanasi district [22]. According to Duchoslav (2002) [3] species composition of the basal zone of walls consists of plant species of nearby vegetation. The vertical wall surfaces of Varanasi city were generally colonized by Achyranthes aspera, Blumea aromatica, Blumea eriantha, Blumea indica, Blumea oxyodonta, Boerhavia diffusa, Catharanthus roseus, Cayratia trifolia, Chloris virgata, Chloris incompleta, Eragrostis amabillis, Eragrostis viscosa, , Ficus benghalensis, Ficus racemosa, Ficus religiosa, Ficus virens var. sublanceolata, Lindenbergia indica, Poa annua, Portulaca oleracea, Portulaca quadrifida, Pteris vittata, Setaria viridis and Tridax procumbens. Colonization of plants on vertical wall surfaces depends on the level of disintegration of mortar, concrete or any other type of binding material [3]. The plants generally colonizing the wall tops of the Varanasi city were represented by Apluda mutica var. aristata, Blumea indica, Blumea oxyodonta, Euphorbia thymifolia, Chloris virgata, Dichanthium annulatum, Ficus benghalensis, Ficus religiosa and Peristrophe bicalyculata. The colonization of plant species is determined by the disintegration of material on the wall tops [3]. Lisci and Pacini (1993a) [4] described the growing conditions of wall plants and the microhabitat created by the substrate inside the cavities of the walls. In present study it was observed that the basal zone of the walls have greater number of species compared to vertical wall surfaces and the wall tops. Dos Reis et al. (2006) [16] also have reported greater number of species on the base than the other zones of the walls. Cavities at ground level in walls are microhabitats with less environmental stress [4]. According to Duchoslav (2002) [3] occurrence of greater number of species in basal zone of the walls is caused by the presence of more moisture and nutrients. It was observed during the study that herbaceous Lindenbergia indica and Tridax procumbens, and the woody Ficus benghalensis, Ficus racemosa and Ficus religiosa were the most common plant species on the walls of Varanasi city. CONCLUSION It can be concluded from the study that the walls of Varanasi city hosts a diverse variety of plant species dominated by the Asteraceae, Poaceae and Fabaceae families. The occurrence of large variety of plant species including woody perennials clearly indicates that the city has grown old with low level of urbanization. REFERENCES

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