Before it had a name: Diagnostic characteristics, geographic distribution, and the conservation of Cupressus tonkinensis (Cupressaceae)

Abstract

In northern Việt Nam the felling of Cupressus for wood and incense has resulted in the decimation of wild cypress populations. Ever since specimens of Cupressus from Việt Nam were first sent to Paris in 1905, they have been inappropriately referred to a variety of names including Cupressus funebris, Cu. torulosa, and synonyms of Callitropsis lusitanica. This taxonomic disarray was somewhat ameliorated in 1994 when a new species-Cu. tonkinensis-was proposed. Unfortunately, the morphological differences between Cu. tonkinensis and similar species were not clearly articulated. As a result, Cu. tonkinensis has generally been ignored or treated as a synonym of Cu. torulosa. These two species can be distinguished by the presence of dimorphic leaves in Cu. tonkinensis and their absence in Cu. torulosa as well as several continuous morphological characteristics including the frequency of resin glands (greater in Cu. tonkinensis) on ultimate segments, and the size of the ovulate cone (smaller in Cu. tonkinensis). The natural habitat occupied by Cu. tonkinensis in a principal coordinates plot of nine monthly climate variables and 40 soil variables is remote from other species. Cupressus tonkinensis habitat is statistically distinct from Cu. chengiana, Cu. gigantea, and Cu. torulosa, but statistically indistinguishable from the habitats of Cu. funebris.Abstract.