Monday, 4 June 2012

Largest leaved Old World bamboo

Ochlandra ebracteata Raizada & Chatterjee is the largest leaved Old World bamboo

Neurolepis elata (Kunth) Pilger [=N. nobilis (Munro) Pilger] and N. glomerata Swallen, found in the New World possess the largest leaf blades in the grass family. During our bamboo explorations in the forests of Kerala we came across a few clumps of the reed bamboo Ochlandra Thwaites with unusually large leaves. This prompted us to draw a comparison of the leaves of Ochlandra with those of Neurolepis Meissner. 

We estimated the leaf area from the linear measurements of leaves (= leaf blades) using the equation A = 0.905 LB, where L = length of leaf and B = breadth of a point midway along the length. Linear measurements were gathered from two sources, (1) from the online World Grass flora and (2) from field i.e the Ochlandra growing regions of Kerala.  From the former the length and breadth of leaf blades of all bamboo species having 20 cm or more in length were collected. For the latter field surveys were conducted for the collection of larger leaves and their measurements were noted discarding the length of acumen. The leaf area of each species was estimated using the higher values of L and B in the case of measurements obtained from online World Grass flora (as the aim was to find leaves with maximum areas) and from actual length and breadth of larger leaves in the case of natural stands. From the above data we prepared a list of species in descending order of their leaf areas.

The largest leaf blade collected by us in Kerala is that of Ochlandra ebracteata Raizada & Chatterjee which measured 63.1cm in length and 14.5 cm in breadth with a total area of 828.02 cm2. Thus O. ebracteata represents the species with the sixth largest leaf among world bamboos and the largest in the Old World though it accounts only 1/16th of the leaf size in Neurolepis elata. O. wightii (Munro) Fischer occupied the second position followed by O. travancorica (Bedd.) Benth. ex Gamble.

Koshy, K.C., K. P. Dintu and B. Gopakumar. 2010. The enigma of leaf size and plant size in bamboos. Current Science 99(8):1025-1027.


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