During ambient conditions, propagules of lichens were most likely observed to start appearing sporadically on the series of circular dents or scars carved around the trunk girth due to the sequential peeling of dead sheaths of the growing Areca catechu. After the rains, the 0.3 to 0.5 inch wide dents may hold substantial amount of water enough to sustain the moisture needs of the growing lichen. The dents or scars were observed to be hard, rough but chlorophyllous for some and not fibrously slippery thus allowing the propagules to attach and initiate growth by centrifugal spreading. The bases of the upwardly directed modified leaves of the palm trees serve as temporary reservoir of rain water that streams downward thus bathing particular portions of the trunk. Lichen growth and reproduction on palm trees may be continuously maintained in this manner. Palm trees have been observed to harbor crustose or powdery forms of lichens luxuriantly sometimes almost covering the whole trunk compared to other woody trees nearby. The most luxuriant growth was observed on the slim trunk of Areca catechu, followed by Corypha elata and the least was seen in Cocos nucifera . The architectre of the trunk of the Cocos nucifera having irregular dimensions may be responsible for the discontinuous pattern of lichen growth. Cocos nucifera about eighth to ten meters away from the sea's spray zone were not observed to harbor lichen growth. A Terminalia catappa in similar location was found to harbor lichen growth on its trunk facing away from the sea.

Key words: Areca catechu, centrifugal growth, circular dents, Cocos nucifera, Corypha elata, crustose or powdery lichens, scars