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Quantitative and qualitative variations in hexane and acetone extractables from 10 euphorbs were studied and compared with guayule. There were significant differences in quality as well as the quantity of oligomers in various euphorbs. Hexane extractables were in relatively lower proportions than the acetone extractables. A regression analysis of the acetone- and hexane-extractable fractions revealed that there was a good correlation. Average molecular weight ((M) over bar w) of polyisoprenes was determined by gel permeation chromatography. in all the taxa investigated, (M) over bar w was far less than that observed in guayule. There appeared to be no correlation between hexane extractables and average molecular weight. GPC chromatograms of the euphorbs showed a unimodal distribution, while most of the cultivars of guayule had a bimodal distribution. The molecular weight distribution (Mwd) range was very narrow in most of the species investigated. High resin content and lack of minimum threshold temperature appear to hinder synthesis of cis-polyisoprenes. Apparently, latex flow seems high but the latex has very low (M) over bar w. Poor biomass and high moisture content further restrict their usefulness.