TICtalk • 2012

A New Affects Taxonomic Classification in the

submitted by John Russell

The discovery of a new conifer species and configuration; however this classification its subsequent phylogenetic description has did not catch on (Little et al. 2004, Mill and Essentially that had significant and controversial impacts Farjon 2006). Recently, new molecular Callitropsis as on classification within the Cupressaceae evidence from Gadek et al. (2000) indicated the name we including yellow (formerly known that nootkatensis was closely should now use, so as Chamaecyparis nootkatensis). In this article related more to the genus (http:// following Little (2006) I will outline the cause of this disagreement en.wikipedia.org/wiki/Cupressus ) than the new scientific and how it is influencing the taxonomic to Chamaecyparis. There was also growing name for yellow classification of the new world evidence that showed the species was unique cypress is Callitropsis including yellow cypress, for which I will within the Chamaecyparis including duration nootkatensis. refer to by various genera as it was then of maturation, seed wing anatomy, commonly accepted. wood anatomy and secondary chemistry, fertilization and low cross-compatibility In the fall of 1999 a new conifer species was of microsatellite primers among others found in a moist forest on limestone karst (citations in Little et al. 2004). Chamaecyparis ridges in northern Vietnam. This species had nootkatensis also hybridizes with a number a morphological resemblance to others in the of Cupressus species (e.g. ); Cupressoideae subfamily of the Cupressaceae however there are no documented hybrids especially Chamaecyparis and Cupressus. with other Chamaecyparis species. We However after a thorough morphological have been hybridizing Chamaecyparis description, the conifer was distinct enough nootkatensis with both Chamaecyparis and to warrant a new genus and species, and was Cupressus species over the years at Cowichan given the new scientific name Lake Research Station and in New Zealand and (xantho=yellow, cyparis=cypress) vietnamensis have had success only with the latter genus. Farjon & Hiep (Farjon et al. 2002) with the common name of Vietnamese golden This leads us to the dilemma of naming cypress. The most distinct morphological Chamaecyparis nootkatensis. Compelling feature of this species is the occurrence of evidence has shown that this species is a juvenile, intermediate and mature foliage in sister taxa with Xanthocyparis vietnamensis the upper crown (Farjon et al. 2002). Upon (Farjon et al. 2002, Little et al. 2004, Mill closer examination including molecular data, and Farjon 2006, Little 2006) coupled with a number of authors placed Chamaecyparis the above evidence that it is unique within nootkatensis as a sister taxa. Morphological Chamaecyparis. Farjon et al. (2002) correctly similarities included seed cones with 4 (to placed both species in a new genus since they 6) bract-scale complexes (Farjon et al. 2002), were clearly distinct from those in Cupressus apically distributed ultimate branchlets and Chamaecyparis. However it seems that and externally dimorphic mature leaves taxonomic precedent favours Callitropsis (Farjon et al. 2002, Little et al. 2004). It was under the rules of the International Code of proposed initially by Farjon et al. (2002) that Botanical Nomenclature (http://en.wikipedia. Chamaecyparis nootkatensis be renamed as org/wiki/International_Code_of_Botanical_ Xanthocyparis nootkatensis. This genus name Nomenclature ), as the earlier-published was later disputed by Little et al. (2004) in name has priority over Xanthocyparis if that which they proposed the name Callitropsis for genus includes Chamaecyparis nootkatensis both species – more on this later. (Little et al. 2004). Chamaecyparis nootkatensis has had an A proposal was put forth by Farjon and interesting taxonomic past being first placed others at the 2011 International Botanical in Cupressus in 1824, and later transferred Congress to use Xanthocyparis but it did to Chamaecyparis in 1842 (Little et al. 2004). not make it to the committee that decides To complicate matters further, Orsted on taxonomic conflicts. Essentially that created the monotypic genus Callitropsis in leaves Callitropsis as the genus name we 1865 for Chamaecyparis nootkatensis because should now use, so following Little (2006) of the somewhat unusual ovulate cone the new scientific name for yellow cypress

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is Callitropsis nootkatensis (D. Don in Literature Citation Lambert) along with its sister taxa Callitropsis vietnamensis (Farjon&Hiep). Gadek, P.A., Alpers, D.L., Heslewood, M.M. The Cupressaceae taxonomic controversy and Quinn, C.J. 2000. Relationships doesn’t end here. Little (2006) states that within Cupressaceae sensu lato: a “classifications within the Cupressoideae combined morphological and molecular have been contradictory as a result of approach. Amer. J. Bot. 87:1044-1057. Given that it is now taxonomically incomplete intuitive analyses closely aligned with combined with an emphasis on characteristics Farjon, A., Hiep, N.T., Harder, D.K., Loc, cypress species and of ovulate cones to the exclusion of P.K. and Averyanov, L. 2002. The new that the description vegetative, anatomical, and chemical genus and species in Cupressaceae as a false cedar using characteristics”. Little alsopresented (Coniferales) from northern Vietnam, a hyphen1 is rather exhaustive evidence supporting that the Xanthocyparis vietnamensis. Novon. 12: outdated, and yellow New World species of Cupressus are more 179-189. is an apt description for its heartwood closely related to Callitropsis than they are Little, D.P. 2006. Evolution and colour, then yellow to the Old World Cupressus species. Little circumscription of the true cypresses cypress seems proposes to restrict Cupressus to the Old (Cupressaceae: Cupresssus). Systematic appropriate. World species and to expand Callitropsis Botany. 31:461-480. to include New World species currently classified asCupressus . Species from Juniperus Little, D.P., Schwarzbach, A.E., Adams, and Chamaecyparis would still be recognized R.P. and Hsieh, C.F. 2004. The separately. Although compelling, this circumscription and phylogenetic reclassification is currently not universally relationships of Callitropsis and the accepted mainly because the relationship newly described genus Xanthocyparis between Callitropsis nootkatensis, Callitropsis (Cupressaceae). Amer. J. Bot. 91: 1872- vietnamensis and the New World species 1881. of Cupressus has not been resolved. Little Mill, R.R. and Farjon, A. 2006. Proposal to (2006) states that this may change in the conserve the name Xanthocyparis against future based on research currently underway Callitropsis Öerst. (Cuppressaceae). involving additional character data. Taxon. 55: 229-231. On a less significant note, the common name of Callitropsis nootkatensis is also being debated. The species has been known under a number of common names including yellow-cedar, Nootka cypress Alaska-cedar and yellow cypress. Given that it is now closely aligned with cypress species and that the description as a false cedar using a hyphen1 is rather outdated, and yellow is an apt description for its heartwood colour, then yellow cypress seems appropriate. This common name has been used in British Columbia for quite some time along with yellow-cedar. 1. True cedars ( spp.) are in the Pinaceae and convention dictates that any common name referring to a false species Figure 1. Drawing by Jodie Krakowski. should have a hyphen or be one word (e.g. Douglas-fir, western redcedar).

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