TAXONOMY AND ECOLOGY OF TWO SYMPATRIC SPECIES OF LITSEA (L. BOURDILLONII GAMBLE AND L. FLORIBUNDA (BLUME) GAMBLE), LAURACEAE ENDEMIC TO WESTERN GHATS

Fasila P. K 1 , Pradeep A. K. 2 , Amitha Bachan K. H 3 , Girija T. P 3 and Fouziya T. A 4 . 1. PhD Fellow, Research & PG Department of Botany, MES Asmabi College, P. Vemballur, Thrissur Dt. Kerala 680671, India. 2. Assi. Prof., and Research Guide, Department of Botany, University of Calicut. 3. Assi. Prof. and Research Guide, Research & PG Department of Botany, MES Asmabi College, P. Vemballur, Thrissur Dt. Kerala -680671, India. 4. Fellow, Western Ghats Hornbill Foundation, Aryanak Mathilakam, Thrissur Dt. Kerala -680671, India. ...................................................................................................................... Manuscript Info Abstract ......................... ........................................................................ Manuscript History


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India of which 18 species are endemic to different ecoregions Singh, 2011;IUCN 2018). Out of the 18 species of Litsea endemic to India 14 are endemic to Western Ghats and other 4 are endemic to North-East India.
There are 22 species distributed in Kerala of which 14 are Western Ghats Endemics, 4 are threatened species (IUCN, 2018). This study aims to provide a detailed account of morphology and taxonomy, distribution and ecological niche of the two sympatric species of litsea i.e. Litsea floribunda (Blume) Gamble endemic to the Western Ghats and Litsea bourdillonii Gamble endemic to the Southern Western Ghats. Both the species are small trees, morphologically very similar and distributed in the Evergreen and Wet Evergreen forests almost occupies a similar niche and are seen together.

Methodology:-
The specimens were collected (vegetative stages, multiples samples of flowering, young and mature fruiting stages and seeds) during field visits in important forest areas of Kerala ranging from Ponmudi-Agasthyamala region of Thiruvananthapuram District in the south upto the Silent Valley National Park in North. Detailed ecological studies were conducted in the evergreen forest areas of Vazhachal Forest Division and Parambikulam Tiger Reserve. The Sholayar -Malakkappara region was selected for detailed study because of the sympatric occurrence of these two species in the region. The identity of the specimens were confirmed by using important floristic works Flora of British India, (Hooker, 1886), Flora of presidency of Madras (Gamble, 1925) and regional floras (Manilal, 1988 ;Sasidharan & Sivarajan, 1996;Mohanana & Sivadasan, 2002;Anil Kumar et al., 2005). The herbariums were prepared following Van Balgooy (1987). Author citation and nomenclature was done by following Authors of Plant Names by Brummitt and Powel (1992) and The Plant Book (Mabberley, 2008).
Simple phytosociological methods were used to understand the community composition of the associated vegetation of each species and also the niche occupancy. Transects of 250 m long were laid at 12 random grids in the Sholayar area of the Vazhachal forest Division. All the important trees were identified and counted for their numbers with a width of three meters along the transect. GPS readings were taken at the beginning, end and regular intervals in each transects. The actual distance travelled was calculated plotting the GPS reading on Map Info GIS software.
The specific position of the selected species in the vegetation, their associated species and their population characteristics were estimated. Relative Density (RD) and Relative Frequency (RF) were calculated to elucidate Importance Value Index (IVI), an index to understand the importance of a particular species in a community. The species were then sorted to various height class such as Large, Medium, Medium and Small. The species with highest IVI values in each height class were identified as dominant associated species and hence the community composition and the niche of the two Litsea species under study were revealed.
GPS reading were taken from the study area for the two species of Litsea and collection locations were identified from herbarium specimens of each species during examination of specimens collected by various authors. The maps were created by plotting collection location of the two species across Google Map Interface. Each species were plotted with as specific colour tag.

Morphology, Taxonomy and Systematic Treatment Litsea Lamarck
Encycl. 3:574. 1972, nom. cons. Litsea is an evergreen, rarely deciduous trees or shrubs. Leaves alternate or sometimes opposite, penninerved. Flowers dioecious, in umbellules of several together, usually 4-6 but in some cases up to 15, supported by 4-6 or more concave involucral bracts; the umbellules sessile or pedicelled in axillary or lateral clusters or in recemes, rarely solitary. Perianth tube in male flowers 0 or very small, in female flowers funnel-shaped; lobes normally 6, sometimes more, sometimes 0 or very early caduceus, equal or unequal. Stamens in male flowers normally 9 or 12 in four rows, those of rows 1 and 2 usually eglandular, those of row 3 and row 4 when present with 2-glandular filaments; all stamens with 4 cells, the cells intorse or the lower pair lateral; ovary 0 or rudimentary. Staminoides in female flowers as the stamens of the male flowers but those of the outer rows clavate or linear, those of the inner rows subulate and 2-glandular; ovary enclosed in the perianth-tube or free; style thick, often curved; stigma dilated, Gamble, Bull. Misc. Inform. Kew 1925: 131. 1925& Gamble, Fl. Pres. Madras 1237. 1925Mohanan, Fl. Quilon Dist. 347. 1984 Small to medium sized trees upto 8-12 m high; branchlets are brownish to black coloured, tomentose, bark smooth, young shoots are reddish coloured. Leaves dark green, obovate to obovate-oblong, cuneate at base, acute at apex, reticulate venation, entire, simple, estipulate, alternate, 10-12 pair nerves under the leaf lamina it is exposed and at upper surface it is impressed, pinnate, pubescence on lower surface of leaf; petiole 10-15 mm long, stout, dark brown tomentose, Flower unisexual, sessile -subsessile, in axillary or lateral clusters of 2-5, flowers 4-6 in umbellule, peduncle thick, brown, flowers yellow to pale greenish bract two lobed, brown, 5 mm long, concave, densely white-tomentose; stamens 9-12, ovary half inferior, ovoid, style thick, stigma dialated. Fruit a berry, oblong, 12-14 mm long, seated on cupule like perianth tube, sessile closely attached to stem. Seeds obovate, 10-12 mm long, brown, smooth, with thin testa.

Community Composition and Niche
Importance Value Index of the two species and other species within the associated vegetation in the study area showed that both species sympatrically occur in the lower tree strata of the medium elevation wet evergreen forests dominated by Palaquium-Cullinia-Mesua type at an altitude range 700 -1200m MSL.