Angiosperm diversity of the Theosophical Society campus , Chennai , Tamil Nadu , India Sheeba

This paper deals with the list of flowering plants from the Theosophical Society campus (TS), Chennai. The Theosophical Society campus is the second largest green patch in the city of Chennai, next to Guindy National Park. A total of 449 taxa have been recorded comprising 161 trees, 84 shrubs, 179 herbs and 25 climbers that are distributed in 353 genera, represented in 85 families, 11 super orders and 35 orders as per the APG III classification. Superorder Fabids and Lamids account for about 49% of the taxa. Paleotropical elements (66%) dominate the TS campus followed by Neotropical elements (31%). The present study reveals that TS campus has a rich and diverse exotic flora. The garden department of this protected campus takes care of conserving the floral diversity. Hence, Theosophical Society campus can be considered as a major biodiversity heritage site and an indispensible lung space for the city of Chennai.


INTRODUCTION
The interaction between plants and people is as old as history of human origin and civilization.Traditional societies throughout India have valued plant species and preserved them.Though preserving plants and forests in their wild state has been in existence from ancient times, cultivating and propagating plants of economic importance including ornamentals started much later when settled agriculture came into vogue.Human beings play a major role in the introduction and spread of non-native species through activities such as agriculture and horticulture, increasing the species richness of plants in urban habitats (Reichard and White 2001).Cities are among the most important ecosystems transformed by anthropogenic activities (Antipina 2003).Altered vegetation is an important component of transformed urban ecosystems.Urban societies have influenced the growth of gardens for social, cultural and emotional needs.Many temperate and tropical plants were introduced into India during colonial regime which brought changes in the composition of the exotic flora of India, especially of the urban areas.However, exclusive taxonomic studies on the exotic flora are limited.
The city of Chennai which had its origin about 373 years ago as a group of fishing hamlets, has now developed into one of the major metropolitan cities of India (Muthiah 2008).Many areas of the present Chennai had earlier supported lush vegetation either in the form of thoppu (plantation) or in the form of natural forests.However, the major green space in Chennai is now restricted to two areas namely Guindy National Park, and its adjoining areas, and the Theosophical Society, Adyar.
This study is an attempt to record the flora of the Theosophical Society campus (TS) which has been the centre for its International activities for over 100 years.The TS campus retains natural vegetation along the banks of the Adyar River and coast and has a high concentration of exotic species, including several rare ones.

Study area
The study area is the international headquarters of the Theosophical Society (TS), (Figure 1) located in Adyar on the southeastern coast of Chennai and covering an area of about 1.1 km 2 .The society was founded in 1882 by Madam Blavatsky and Colonel Olcott.The society attained great prominence during Dr. Annie Besant, who was the second president of this society.It has a rich diversity of trees and shrubs from different parts of the world.The campus is bounded on the north by Adyar River (Figure 2), on the south by Besant Nagar, on the

LISTS OF SPECIES
Irwin et al. | Angiosperm diversity of Theosophical Society Campus (Jain and Rao 1977).Herbarium sheets were deposited in Foundation for Revitalisation of Local Health Tradition (FRLHT), Bengaluru.

Data analysis
The data was analyzed based on various parameters such as habit, nativity, rare and noteworthy trees including exotics.The phytochorionomic categories of the species were analyzed based on Takhtajan (1986).The plant species are enumerated and arranged as per Angiosperm Phylogeny Group III Classification (APG III 2009;Stevens 2012).The nomenclature of the species west by Gandhi Nagar and on the east by Bay of Bengal.The soil is sandy along the seashore and less sandy to loamy towards inland and clayey towards the river bank.Typical coastal climate prevails and is very hot and dry from March to May.Temperature dips to its minimum from December to February and is regarded as the cold season in Chennai.The relative humidity ranges from 63-86%.

Data collection
This study was carried out in two phases.The first phase of the study was carried out from August 1994 to December 1996.Weekly field trips were made during this period.After a gap of about fifteen years, periodical visits were made from April 2010 to December 2011.During this period the plants earlier recorded were critically evaluated.Voucher specimens were collected after obtaining permission from the authorities of the TS and were duly tagged.Field observations were made and plants were photographed.Plant specimens were identified using relevant floras and pictorial guides (Brown 1862;Mayuranathan 1929;Bailey 1949;Gamble and Fischer 1957;Backer and Brink 1965;Swarup 1967;Matthew 1969;1999;Graf 1978;1981;1992;Dassanayake andFosberg 1980-1991;Bose and Chowdhury 1991;Sanjappa 1992;Livingstone and Henry 1994).The collected materials were poisoned using standard herbarium techniques

RESULTS AND DISCUSSION
The first exclusive study on the flora of the TS campus was carried out by Rao (1957) who reported about 223 taxa consisting of 119 trees, 12 shrubs, 79 herbs and 13 climbers.After a gap of about 37 years the polypetalous and gamopetalous flora were studied by Irwin (1996, unpublished data) and monochlamydeous and monocots were studied by Thomas (1997, unpublished data) and reported a total of 421 taxa consisting of 141 trees, 79 shrubs, 173 herbs and 28 climbers.Members/visitors from many parts of the world have introduced several plants into the campus.
The present study documents a total of 449 taxa (Table 1) distributed in 353 genera, representing 85 families as per APG III classification.These taxa are distributed in 11 superorders (Figure 3) and 35 orders.26% of the taxa are reported from the superorder Fabids, 24% from superorder Lamids, 22% from superorder Malvids and 16% from superorder commelinids.Order Fabales (61), Lamiales (55), Sapindales (51) and Poales ( 48) account for about 48% of the species in the TS (Figure 4).Of the 449 taxa 161 are trees, 84 shrubs, 179 herbs and 25 climbers (Figure 5).Family Fabaceae and Poaceae are represented by about 23% of the taxa.The other dominant families are given in Table 2. Thirty-five families are represented by single species each.The genus Euphorbia tops the list with seven species, Phyllanthus with six species, followed by Cassia and Ficus each with five species and Bauhinia, Hibiscus, Indigofera, and Senna four species each.
The native flora of the TS campus consists of three different elements, namely mangroves, psammophytes, and tropical dry evergreen.Avicennia marina and Excoecaria agallocha are restricted to the tidal zone along the Adyar estuary.These are the only two mangrove species seen in the TS campus.This is the only locality for the entire city of Madras where these species naturally occur in abundance.On the eastern side of the campus as well as the interior portions of the northern side have sandy soil.Bulbostylis barbata, Cyperus arenarius, Oldenlandia stricta, Ipomoea pes-caprae and Pupalia lappacea are the most common and predominant psammophytes in this region.Pamburus missionis is the only tropical dry evergreen element occurring in the campus.The ground flora is dominated by grasses such as Alloteropsis cimicina, Apluda mutica, Urochloa reptans, Pennisetum ciliare, Chloris barbata, Cynodon dactylon, Dactyloctenium aegyptium, Digitaria ciliaris, Echinochloa colona, Heteropogon contortus, Panicum repens, Setaria barbata, and Trachys muricata.The rest of the areas have cultivated plants and coconut groves (Figure 6).Some of the noteworthy plants are Berrya javanica, Bismarckia nobilis, Brownea grandiceps, Brownea macrophylla, Catesbaea spinosa, Goniothalamus salicinus, Gustavia superba, Haplophragma adenophyllum, Jacquinia aculeata, Nypa fruticans, Oncoba spinosa, Peltophorum africanum, Saraca thaipingensis, Sterculia apetala, Tecomella undulata, Triplaris weigeltiana, and Voacanga grandifolia.Fourteen species of palms are reported from the TS campus of which Corypha macropoda is a native palm.This campus has an avenue of Swietenia mahagoni, planted by representatives of several member countries.The big banyan tree (Figure 7) with branches spanning 75 m from north to south and 51 m from east to west attracts tourists from all parts of the world.This delightful sanatorium can afford shelter for thousands of people and is a nesting place for several birds.The main trunk of this large banyan was uprooted by a cyclone during November 1992.Another plant of interest is the palm, Nypa fruticans which is grown in a circular tank (Figure 8).Nypa fruticans is a mangrove palm of Andaman and Nicobar Islands, and on the mainland, this palm is recorded only from the TS campus.The sandy and open areas are a home to many naturalized invasive species which include Prosopis juliflora, Tridax procumbens, Lantana camara, Hyptis suaveolens, Antigonon leptopus, and Croton bonplantianum.
Paleotropical elements (66%) dominate the TS campus followed by Neotropical (31%), Holarctic (2%) and Australian (1%) elements (Figure 9).About 16 species are pantropical.Among the paleotropical plants 39 taxa are reported from Indian Region.Of these, eight species are endemic to India namely: Sansevieria roxburghiana, Pterospermum xylocarpum, Aganosma dichotoma, Wrightia tinctoria, Gardenia gummifera, Eranthemum roseum, Leucas diffusa, and Torenia hirsuta.There are not many changes in the flora of TS when compared with our two phases of studies.Bauhinia × blakeana, Bismarckia nobilis, Carpentaria acuminata, Crescentia alata, Majidea zanguebarica and Terminalia mantaly are some of the additions to the TS campus.Cochlospermum religiosum, Dillenia suffruticosa, Haematoxylum campechianum, Areca triandra, Ceiba speciosa, Licania platypus, Lonchocarpus violaceus are some of the trees the campus has lost due to natural calamities.The present study reveals that the TS campus has a rich and diverse exotic flora.Many of the plants occurring in the campus are uncommon.Such a rich and diverse exotic flora exists because of the efforts of the Garden Department, international members, and those who live on the campus.However, composition of the TS flora consists of nearly an equal percentage of exotic and native species.The campus, located in the highly urbanized Adyar region, acts as a crucial green lung space for the area.

Figure 2 .
Figure 2. Vegetation along the Adyar River bank.

Figure 3 .
Figure 3. Distribution of species in superorder as per APG III.

Figure 4 .
Figure 4. Orders with more than 10 species.

Figure 5 .
Figure 5. Life form composition in the TS campus.
Twenty-seven taxa belong to Tropical Africa, 37 to Indochinese region, six to Madagascan region, 74 to Indomalesian region and 12 to Malesian region.Most of the Neotropical elements are from Caribbean region.Of the 225 native taxa about 44% are herbs and 35% are trees and most of these native species are seen exclusively in cultivation.Few of the taxa are shown in Figures 10-35.

Figure 8 .
Figure 8. Nypa fruticans, a mangrove palm grown in a circular tank.

Table 2 .
Families of angiosperms with more than ten species in the Theosophical Society Campus, Chennai, Tamil Nadu, India.

Table 1 .
List of angiosperm taxa recorded from the Theosophical Society Campus, Chennai, arranged according to the Angiosperm Phylogeny Group Classification III.
ContinuedIrwin et al. | Angiosperm diversity of Theosophical Society Campus
Irwin et al. | Angiosperm diversity of Theosophical Society Campus