The decline in the world supplies of hydrocarbons has lead to the search for alternate sources of fuel and chemicals. Plant species are potential sources of hydrocarbons. Large-scale screening of plants growing in the Western Ghats, Tamil Nadu, India was conducted to assess the hydrocarbon production and the type of isoprene compound(s) present. Three species contained more than 3% hydrocarbon. Sarcostemma brevistigma had the highest concentration of hydrocarbon with 3.6%. Seven species contained more than 2% of hydrocarbons among the plant species screened. The hydrocarbon fraction of Ficus elastica (leaf) had a gross heat value of 9834 cal=g (41:17 MJ=kg), which is close to the caloric value of fuel oil. Six hydrocarbon fractions contained gross heat values of more than 9000 cal=g (37:68 MJ=kg). Of the 13 species hydrocarbon fraction analysed, seven species contained cis-polyisoprene compounds, while two species contained trans-polyisoprenes. Cis and trans polyisoprenes are potential alternative energy sources for fuel and=or as industrial raw materials. Published by

We i~ the leaf shape, venalion pattern, Ifichomes, stomata, and branching of the inflorescence axes in 15 varieties of guayule (Parthenium argentaturo Gray) growing in India. Working from our study objective, we were unable to identify any specific correlation between these macro-and micro-morphological characteristics and rubber content.