During his work and travels, he collected enormous amounts of herbarium material.
Wagner had previously used the size of stomata in herbarium material to tentatively classify the species as a tetraploid.
The Flora work entailed his own basic research, which involved a critical examination of herbarium material and literature and some experimental crops and field studies.
Much additional herbarium material was accumulated during this time, representing both new species and better specimens of known taxa, which highlighted issues with previous interpretations.
In older, dried specimens (such as herbarium material), the droplets may coalesce and hinder the identification of species.
Mackrill established a garden and trial ground for crops in Somerset East, occasionally sending herbarium material to the British Museum.
It was first described in 1977 from dried herbarium material and named in honor of the Dutch botanist Hendrik de Wit.
Ernst studied herbarium material in 1961, and Casper used his description when publishing his monograph of the genus in 1966.
Danser divided the genus Nepenthes into six clades based on observations of herbarium material.
The herbarium material examined by Cheek and Jebb exhibited spurs that were basally 5-branched, with each branch being secondarily ramified.