Hierarchical cluster analysis (HCA) of metabolic fingerprinters of <i>D</i>. <i>officinale</i> and <i>D</i>. <i>huoshanense</i>.

<p>“Fe” indicates <i>D</i>. <i>officinale</i>, and “M” indicates <i>D</i>. <i>huoshanense</i>. The numbers 1, 2, and 3 indicate the corresponding growth years of <i>Dendrobium</i>. The letters a, b,…, f indicate repeats of the same sample.