Incorporating ecological context: a revised protocol for the preservation of Nepenthes pitcher plant specimens (Nepenthaceae)

Pitcher plants of the family Nepenthaceae are vines or subscandent shrubs which produce modified leaf organs that in most species serve to attract, trap, retain and digest animals for nutritional benefit. The sole genus within the family, Nepenthes, is abundant and diverse in Malesia. Previous taxonomic treatments of Nepenthes have relied almost entirely on the morphological features of the plants, with characteristics of the pitchers, inflorescences, leaf blades and indumentum being the most informative. Recent ecological research demonstrates that unique morphological characteristics and trap geometries provide useful taxonomic information, but this is often lost or obscured when specimens are prepared for herbaria by pressing them. In this paper, we demonstrate the value of ecological information in distinguishing between controversial montane Bornean taxa and provide a revised protocol for the collection and preparation of Nepenthes specimens, which is designed to maximise the amount of ecological information retained in herbarium material.