Ethnomedicinal knowledge among the Malayali tribal of Chitteri hills, Eastern Ghats, Tamil Nadu, India

The present study was aimed to document the ethnomedicinal knowledge among the Malayali tribal of Chitteri hills Eastern Ghats of Tamil Nadu, India. Field visits were made to the Chitteri hills every month covering all seasons. Interviews with traditional healers and other knowledgeable inhabitants and farmers were conducted. The Malayali tribal people of Chitteri hills use 320 plant species for their day-to-day life, this ethnobotanical exploration revealed they were the habit of using around 216 species of medicinal plants belonging to 200 genera under 45families. Malayali tribes use morphological characters such as bark surface, leaf colour, leaf taste and exudates, underground plant parts and ecology of species as criteria for identification of 135 species belongs to 105 genera under 46 families. The documentation of the knowledge of Malayali tribal identification of plants of Chitteri hills is to be accorded top priority in the preservation of our ancient traditional knowledge


INTRODUCTION
Traditional knowledge of taxonomy is developed from a basic human tendency to recognize plants that are imposed by nature. It is developed from the unique history and culturally defined beliefs, behaviors and preferences of particular traditional societies rooted in a clearly defined geographical area and transmit their knowledge to their offspring's. The universal identification of plants had been ubiquitous since the evolution of systematic botany. Evolution of taxonomy triggered botanists, to explore variety of plant species universally on their biological properties and evolved into the present modern ethnobotany, which emphasize on their, growth pattern and chemical compositions in traditional communities need. With the passage of time, they have developed a great deal of knowledge on the use of plants and plant products. The tribal have their own scientific knowledge of technology and they are still considered to be primitive and traditional bounded. The knowledge is very dynamic and is strongly influenced by indigenous creativity, innovation, rooted in geographical and cultural cognition. The knowledge is very vulnerable to degradation and even complete loss. In this perspective a rich diversity of flora of Chitteri hills was chosen for the study to document with objectives to reveal the criteria used by the Malayali of Chitteri hills use morphological characters and ecology of species as criteria for identification.

Study Area
The present study area, Chitteri hills, a part of Southern Eastern Ghats, is situated in Pappireddipatti revenue taluk of Dharmapuri district in Tamil Nadu, India. Dharmapuri district has the second highest forest cover in relation to the total geographical area, satisfying the criterion of optimum forest cover of 23.62% in its geographical area. The district accounts for 14.3% of the total forest area of the Tamil Nadu.
Chitteri is situated towards North East of Salem district within the geographical limit of 78°15'-78°45' E, longitude and 11°44'-12°08'N, latitude (Figure-1) and occupies an area of about 654.22 Km 2 . Chitteri hills form a compact block consisting of several hill ranges and contain tangled ridges and ravines running in the Northeast and Southwest directions, enclosing many narrow valleys, rivers such as Kallar, Varattar, Kambalai, Anaimaduvu, Kovilar, Sholaiyar and Pungamadauvu rivers and their tributaries drain the area. These rivers are ephemeral in nature and structurally controlled in their flow. The mean maximum and minimum annual temperatures of the study area are 39. 5°C and 19°C, and 31°C and 18°C respectively in winter, average rainfall ranges from 800-1000mm (Harur Forest Office Report, 2007).The Malayali tribes are the most and dominant significant tribes in Chitteri hills of Tamil Nadu. Malayali are the largest Scheduled Tribe constituting 47% of the state scheduled tribal population with a population of 11,482 (Census, 2011). There are 60 villages, out of these, 6 villages are located in plains and 54 villages are located in hill tops.

Field Visits
Field visits were made to the Chitteri hills every month covering all seasons during the period October 2009 -March 2013. Interview and data gathering methods were followed by (Schultes, 1962;Jain, 1995;Rao & Hajra, 1987) . Interviews with traditional healers and other knowledgeable inhabitants and farmers were conducted in order to understand how Malayali tribes identify and utilize plants. In addition, we consulted the who is familiar with the study area. Voucher specimens were collected for the purpose of identification and deposited at Vivekanandha College of Arts and Sciences for Women herbarium.

Documentation of Ethnoidentification of Plants Knowledge
The respondents or informants have been selected for the study based on the following criteria, prevalence of ethnobotanical knowledge in villages and willingness of respondents to share the knowledge. All the respondents are men belong to 25 to 85yrs of age group. Most of the respondents are illiterate or even never crossed primary education.
Data were collected from the tribes using two different methods: 1) The knowledgeable informants are taken to the field and collection of plants specimens with uses of the plants and 2) The other way is to collect all plants available in the village, show them to these informants one by one, and record the information about them. The data were gathered in a series of questionnaire, structured, semi-structured and unstructured interviews regarding plant uses, identification during several field trips. Random interviews with a different sub sect of tribal were used to verify data already collected regarding indigenous knowledge for identification of plant species of Malayali tribes of Chitteri hills was documented.

RESULTS AND DISCUSSION
Periodical trips were made to the study area covering all the hamlets in the hills. Such frequent visits to tribal hamlets helped us to establish a good rapport with the natives, which aided us in the collection day today life. Much patience was needed for gathering information from tribes. Only after successive visits the native divulge their knowledge of plants, especially used for medicine and identification. A cordial relationship was established with them and they feel quite at ease in our company.
Most of the tribes are illiterate and this rules out the possibility of using questionnaires as means of collecting data, though we prepared questionnaires for ethno medicinal plants and traditional knowledge. Dialogues, conversations and subsequent recording of data are made. The authenticity of the information gathered is verified subsequent field trips to other areas with other persons. Such trips helped in verifying the validity of the other related uses. From such field visits, we recorded that Malayali tribal people of Chitteri hills are in the habit of using 320 species for their day today life.

Morphological characters
The Malayali tribes use morphological characters and ecology of species as criteria for identification of 135 species (Voucher specimen number from Vi-432 to Vi-567) belongs to 105 genera under 46 families. Morphological characters are often used to recognize plants of which vegetative features are more commonly used than floral features. Malayali tribes also identify plants based on morphological characters with other associated characters such as taste, colour, succulence of leaves and exudates.

Bark characters
The term bark denotes the tissues outside the vascular cambium of the axis, in either a primary or secondary state of growth. In botanical sense bark is that layer of tissue accumulated on the surface of the plant axis as a result of the activity of the phellogen. Bark is an outwardly visible and prominent macro character especially in trees. Malayali use bark characters as the main criterion for identifying tree species with other characters such as nature and colour of leaf and presence or absence of glands as supportive characters.
Bark features such as nature of the surface, thickness of bark and exudates are used by the Malayali as criteria for identification. Among the species, studied Malayali tribal classified 97 species based on bark features without ambiguity (Table 1)  trees that possess thick bark and. They also identify2 species by inner colour of the bark, they are Bridelia crenulata Roxb. and Pleurostylia opposita (Wall.) Alston, possess red and white colour inner bark respectively.
Bark has been used as a means of recognition of trees by many tribal societies across the world. For example, the tribes in West Africa classified Adansonia digitata L. the Baobab tree into the following four types using bark character such as colour and surface of bark: 1.) Smooth pink bark, 2.) Rough grey bark, 3.) Smooth grey bark and 4.) Black bark (Assogbadjo et al., 2006). Batoros and Bakigas in Western Uganda recognize trees based on life forms. Identifying trees by their architecture is no problem for them (Kakudidi, 2004).
Modern day field-botanists tend to use vegetative features such as bark characters, leaf characters, overall branching pattern and life form for on-the-spot identification of trees. The above mentioned a few publications in which this approach has been standardized.

Plant Exudates
The secretory spaces in the form of cavities or canals are formed by schizogeny or by lysigeny or sometimes by both phenomena combined. Laticifers are cells or series of fused cells containing fluid called latex and forming systems that permeate various tissues of the plant body.
Any discharge from the plants named as exudates by Malayali tribes of Chitteri hills. They use colour of exudates, change of colour in the exudates and the drying characters of the exudates as important criteria for identifying plant species. Malayali tribes consider the milky and white latex as pal in Tamil meaning milky secretion. They recognize 25 milky and white latex yielding plants belonging to 21 genera and 7 families (    the Malayali explain the periodicity of the flow of latex thus: "The rate of flow of latex from the trees is influenced by rainfall. If the species receives sufficient rainfall, the discharge of latex is copious and if the species receives insufficient rainfall, the discharge of latex is scanty". The scientific explanation for this phenomenon is as follows: "Under conditions of heavy rainfall, the cells are supersaturated with water resulting in increased turgour within the plant body. This leads to copious discharge of latex. On the other hand under conditions of drought or scanty rainfall, the cells become flaccid resulting in scanty discharge of the latex". Though they may not know the scientific basis for this phenomenon, it must be agreed that their observation is correct.

Leaf characters
Many tribes familiar with plants use sight, touch, taste, smell and sound for identification and classification of particular plant species. Tribal experience with the organoleptic properties of plants in identification comprises smell, touch and taste (Newmaster et al., 2006). Sensory perception gained by experience is an important tool for plant identification (Getchell et al., 1991;Messer, 1991).
The taste qualities that humans perceive in plants, especially bitterness, have been proposed as significant clue used in primitive societies. Malayali of Chitteri hills have clear knowledge of identification of the species in which leaf characters such as colour, taste, smell, succulence and glands form important criteria.
The Malayali of Chitteri hills also use their personal experience of taste for identification of certain species of plants. By experiencing the leaf taste they identified the following plants Andrographis paniculata, Andrographis alata,, Gymnema sylvestre, Semecarpus anacardium, Albizia procera,,Ceropegia juncea and Clerodendrum inerme. Of the aforementioned plant species, the leaves of Andrographis alata, Andrographis paniculata, Clerodendrum inerme and Semecarpus anacardium are bitter to taste.
The leaves of Gymnema sylvestre also bitter to taste. However, the leaves also have a property of rendering the taste buds neutralized so that the person who has chewed the leaves cannot taste the sweetness for quite a few hours. The tribal people gave jaggery to the present author after a bout of chewing a few leaves of Gymnema sylvestre and the experience were like having a mouthful of sand. The case of Ceropegia juncea locally called "Sempulichan" is more interesting. The taste of the stem changes, in the morning hours tastes is sour, during the noon hours, it is bitter and in the evening hours it is acidic taste.
The Malayali identify / recognize Terminalia tomentosa, Hiptage benghalensis, Mallotus philippinensis and Terminalia arjuna by the presence of glands. In fact, the vernacular name for Terminalia tomentosa is "pillai maruthu" in which the epithet 'maru' means mole. The glands often resemble 'mole'.
Colour of the leaf is another morphological criterion to distinguish between species. Malayali tribes identified eight species by leaf colour is either brown or rusty or black or copper coloured depending on the species. They are Madhuca longifolia (Red colour at new foliage), Anogeissus latifolia (Coppery colour at new foliage), Semecarpus anacardium (rusty colour below), Premna tomentosa (Yellow colour), Vitex negundo (grey pubescent colour), Litsea oleoides (brown colour), Aristolochia indica (whitish colour) and Flueggela virosa (coppery colour in tender foliage).
They identified two species by the succulence of their leaves; they are Aloe vera and Agave angustifolia. The taste and smell are criteria of medicinal and non-medicinal plants. Non-medicinal plants were more often reported to have no smell (or) taste (Classen, 1992 (Yesodharan & Sujana, 2007).
Today we know that raphides (the needle like crystals) of calcium oxalate present in the parenchyma cells of the tubers prick the tongue and mouth causing irritation. When soaked and cooked with tamarind, the tannic acid present in tamarind dissolves the crystals. It is surprising as to how the tribal people knew of the use of tamarind for this purpose.

Ecological characters
Ecological knowledge, such as where a particular plant lives is another important criterion used by the tribes for identifying plants and is perhaps limited to the geographic region. Ecology appears to play an important role in how people classified the flora and fauna of a given area (Areendran & Rao, 2009).
Malayali tribes use landscape characters to a greater extent for identifying certain species of plants. They have accurate knowledge about species such as Ficus tomentosa, Caralluma attuneta and C. umbellata occurring in rocky terrains. Malayali tribes are knowledgeable about connecting certain species to the particular landscape and naming the species accordingly. The naming of plant in vernacular language is based on habitat; one typical example is Caralluma attuneta which is locally called kallumuliyan in Tamil, because this species always occurs in rocky areas.
Albizzia procera an exotic plant that occurs very rarely in Chitteri hills is another good example for this. The bark of this tree, which is used to cure all types of bone fractures, is called Koodumathurai in Tamil. The Tamil word Koodu means meeting or group and 'to join'. This species always occurs in a group of three to five. Its medicinal property joins fractured bones as well. Therefore, the Tamil vernacular name appears appropriate. Decalepis hamiltoni of Apocynaceae is another species growing in rocky areas. Malayali always look for this plant in rocky areas as their root tubes pickled as consumed as food adjuvant. The tubers have cooling properties.
To cite some more examples on their knowledge of the habitat characteristic of plants, they recognize the following plants as riparian. The field notes of the following species: Terminalia arjuna is characteristic riparian (riverbanks) (Matthew, 1995). According to Gamble it is more scarce in Carnatic region except in Tirunelveli and on the West coast; on the banks of rivers and streams. Terminalia crenulatais reported as occasional in riverbanks (Matthew, 1995), Syzygium cumini is representing variety of habitats: Shoals, riverbanks, scrub jungle (Matthew, 1995). It occur in all forest districts, both in plains and in the hills up to 6000 ft., usually along river banks and in moisture localities (Gamble & Fisher, 1935).
Vitex negundo is common in riverbanks or fencing near households (Matthew, 1995). It is present in the dry region up to 5000ft in the hills, on wastelands around villages, on roadsides and the banks of streams, common (Gamble & Fisher, 1935). Bombax ceiba occur from plains to coast, especially along riverbanks; on the deciduous belt of the hills to 800m (Matthew, 1995), Drosera indica is bloom up with the monsoons (unless in perennially moist ground) (Matthew, 1995) and wet places in hills. According to Gamble Mangifera indica, occurs in ravines up to 4000ft. Mitragyna parvifolia is often reported along rivers and foothills to 800m (Matthew, 1995). Pongamia pinnata represent mostly by banks of rivers, in ravine (Matthew, 1995). It is present from coastal forest to tidal riverbanks; inland chiefly along streams and rivers in most districts in the hills up to 3000ft (Gamble & Fisher, 1935) attests to their riparian nature.
Just as a field-botanist has his own scientific approach towards identifying plants in order to pick useful ones, native tribes also have their own approach based on direct observation and macro characters and this serves the purpose. Therefore, we should not dismiss the traditional knowledge of the tribal people as something without scientific basis.
In conclusion, the identification of the usefulness of a plant by organoleptic characters as practiced by the tribal people around the world may be a simple and useful tool to those who do not have a formal botanical training. This knowledge is transmitted orally from generation to generation in the tribal population. Though for scientific purposes this approach of identification of plants cannot be the sole basis, it is certainly useful as it offers supportive field characters for confirming identification. In this context, it is recommended that such indigenous knowledge is documented and incorporated in the floristic publications of the regional floras.