Table 5 ANOVA results from for leaf area calculated in the allelopathy experiments. Asterisks represent level of significance: (***) for P value < 0.001, (**) P value < 0.01, (*) P value < 0.05, (.) P value < 0.1.

From: Interspecific competition with the American Xanthium orientale L. as a possible cause of the decline of the Old-World X. strumarium L.