SAVILLO, ISIDRO. Assistant Professor III, Iloilo State College of Fisheries, Barotac Nuevo, Iloilo, Philippines 5000. - Growth of Lichens on Palm Trees.
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