The effect of preservation methods on plant morphology

Application of conventional (plant pressing followed by air drying) and Schweinfurth drying techniques to different plant taxa is shown to result in both significant contraction and, occasionally, significant expansion of plant organs. The results are taxon dependent. The Schweinfurth drying process usually results in greater shrinkage than conventional drying. Herbarium specimens are shown to exhibit significant differences in the dimensions of plant organs as compared to fresh material. Organ accessibility and availability can also have an impact on the dimensions recorded and, as with the drying process, an impact on the correct recognition of taxa. The lack of discussion of these important differences, their impact on other taxonomic processes and suggestions for further investigation, for example the use of spirit preserved material and rehydration of herbarium material, are highlighted.