Lichen floral studies on Artocarpus heterophyllus Lam. tree trunk in different eco - regions of Sri Lanka

Abstract

Information on lichen flora in Sri Lanka is scarce. Therefore a study was carried out to investigatelichens growing on a tree species common to all five eco regions (Montane, Wet, Intermediate, Aridand Dry zone) of Sri Lanka. The common tree species found in all regions was Artocarpusheterophyllus Lam. (jak). Lichen flora found on bark of jak trees between 1.5 m and 2 rn above theground level was studied. Six hundred and sixty three specimens from hundred and twenty trees werestudied. Twenty five genera and thirteen families were found among them. Twenty genera werefound to be crustose and five were folioses. No fruticose lichen was found in any region. Of allidentified lichens 40% were belonged to the family Graphidaceae and it was the most frequentlyfound lichen family in all regions and the second highest (17%) was belonged to family Phyciaceae.The most frequently found genus was Graphis.

Heterodermia and Pertusaria were found only in montane zone while Leptogium was found only inlowland wet zone. Thelotrema. Ocellularia. Myriotrema and Chrysothrix were found only inIntermediate zonc. Parntelia was restricted to wet zone while Dirinaria, Dimerella and Porinawere restricted to dry zone, Differences in distribution of some of these lichens can be explainedwith rain fall, temperature and humidity.