Trunk Length and Frond Size in a Population of Nephelea tryoniana from El Salvador

stipes relative to lamina length than tall tree ferns of the same species. This study was done to determine how total frond length, lamina length and stipe length vary within a population. In April 1979, measurements were made of 146 fronds on 45 individuals of Nephelea tryoniana Gastony from a dense cloud forest at 2250 m in Bosque Montecristo, a wildlife preserve in northwest El Salvador. The forest is described more completely in Seiler (1981). The trunk length of each tree was measured, as well as the stipe and lamina length of all undamaged fronds. Usually three fronds per tree were measured, but occasionally four or five or as few as two per tree were measured. The majority of the fronds were sterile, but the presence of fertile fronds should have no effect on the results, for fertile and sterile leaves are practically monomorphic in Nephelea (Gastony, 1973). RESULTS The length of the fronds of a tree is fairly constant. The standard deviation within a tree averaged 4.55% (s=2.96, n=45). Analysis of 139 fronds on 43 trees indicates frond length is weakly related to trunk length (r=0.39, P<0.01). Two of the 45 trees were not included in the statistical analysis for reasons that will be