The few hundred known remaining trees are generally in sites where it is too hard to cut them and remove the timber. ![]() The species itself requires urgent conservation action in the ordinary sense because it has been locally overexploited for its very fine, fragrant timber. Even if each species were placed in its own genus, the name Xanthocyparis is not technically available, and Golden Vietnamese cypress would either need a new generic name or Xanthocyparis would have to be protected from the rules of nomenclature by formally conserving it nomenclaturally. Alternatively, since DNA studies show that they are most closely linked to the New World cypresses, if the latter were treated as a separate genus from the Old World cypresses, Alaska and Golden Vietnamese cypress would be placed in the New World genus even though they have two cotyledons like the Old World species. While they are placed in Cupressus here, in line with several aspects of their morphology and biochemistry, their ability to cross with other species of Cupressus, and some DNA studies, other work suggests a more complicated picture in which each could represent a separate genus. The relationships of Vietnamese and Alaska yellow cedars are somewhat uncertain. ![]() ![]() Unfortunately, because Alaska yellow cedar, is the type and only species of a much earlier described genus, Callitropsis Oersted, Xanthocyparis is nomenclaturally superfluous and cannot be used for these two species if they are placed in a genus separate from Cupressus. Unlike the two famous conifer genera first described in the middle and late 20 th century, Metasequoia from China and Wollemia from Australia, the proposed Xanthocyparis was founded not just on a newly described species but also on another one that has been known for almost 200 years, Alaska yellow (Cupressus nootkatensis). Golden Vietnamese cypress caused a considerable stir when it was formally described in 2002 because it was assigned to a new genus. Seeds one to three per scale, 4.5-6 mm long, light brown or reddish brown, the wings about as broad as the body. Seed cones nearly spherical, 9-12 mm in diameter, greenish brown at maturity, shiny or somewhat dulled by wax, with two (or three) pairs of seed scales, each with a prominent, pale, triangular point on the face. Pollen cones 2.5-3.5 mm long, 2-2.5 mm wide, with five or six pairs of pollen scales, each with two (or three) pollen sacs. Tips of scale leaves elongate, narrowly and sharply triangular, loosely pointed forward or somewhat spreading, those of the facial leaves overlapping the base of the pair above them. Adult scale leaves on branchlets 1.5-3 mm long (to 5 mm on main shoots), light green at first, darkening to brownish green with age, occasionally with conspicuous, whitish, small stomatal patches, strongly differentiated into lateral and facial pairs, both types keeled, obscurely glandular. Branchlets bearing adult foliage flattened, 0.8-2(-3) mm wide, mostly arranged in flattened, frondlike sprays by branching from lateral leaf pairs, horizontal or drooping with upturned tips. Juvenile leaves 1.5-2 cm long, sticking straight out from the branchlets in alternating whorls of four separated by 4-5 mm. Branches with juvenile and transitional foliage present on adult trees. ![]() Crown conical at first, becoming dome-shaped and irregular with age, with long, slender, upwardly angled to horizontal branches. Bark reddish brown to purplish when fresh, weathering brown to grayish brown, becoming shallowly furrowed and peeling in long, narrow strips. Tree to 15 m tall, with trunk to 0.5 m in diameter. Synonyms: Callitropsis vietnamensis (Farjon & T.H.Nguyên) D.P.Little, Xanthocyparis vietnamensis Farjon & T.H.NguyênĬommon names: Golden Vietnamese cypress, Vietnamese yellow cedar (English), Bách vàng (Vietnamese) Scientific name: Cupressus vietnamensis (Farjon & T.H.Nguyên) Silba 2005
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