Silba, J. (2005). A monograph of the genus Cupressus in the twenty-fisrt century. J. Int. Conifer Preserv. Soc. 12(2): 100.

27.                                                               100 Cupressus vietnamensis (Farjon et Hiep) Silba, Combination nova. Basionym : Xanthocyparis vietnamensis Farjon et Hiep in Farjon et             al., Novon 12: 180 (2002). Synonymy: Callitropsis vietnamensis (Farjon et Hiep) D. P. Little,           in Amer. J. Bot. 91 (11 ) : 1 879 (2004).   A small tree, resembling Cupressus nootkatensis in general aspects of its foliage and cones.Or small to medium sized tree with a dense semi-rounded crown, the trees reaching 10-15 m. tall. Bark purplish to red-brown exfoliating in thin flakes, later becoming gray-brown. Main branches relatively long in length, more or less spreading horizontally. Seasonal branchlets spreading in overlapping sprays, slightly drooping, with polymorphic foliage present (scale-like and needle-like foliage occuring on the same branches). Juvenile leaves in whorls of four, decurrent, 4-5 mm.long, linear, margins entire, stomata in two whitish bands on the abaxial side only. Adult foliage occuring on flattened branchlets and disposed in a flattened plane. Adult leaves decussate, imbricate, dimorphic, ovate-rhombic, bluntly acute:, grassy-green to yellowish-green color,1.5 to 3 mm. long and 1-1.3 mm. wide, glands inconspicuous and in a depression, the stomata mostly on the adaxial side. Pollen cones terminal and solitary, 2.5 to 5 mm. long, with 10-16 microsporophylls with erose-denticulate margins. Female cones sparse, sometimes 2-3 grouped together, green, maturing dark or dull brown, subglobose, 9-11 mm. long by 10-12 mm. wide when opened with 4-6 valvate or subpeltate scales, the scales relatively thin, with a prominent erect or decurved umbo 1-2.5 mm. long. Seeds 1 to 3 per fertile bract or more, ovoid or irregular, 4.5-6 mm. long by 4-5 mm. wide, light brown to red-brown, seed wings 0.5- 1 mm. wide and light colored. Seedlings with 2 cotyledons. Distribution: This species is limited in its range to moist karst forest in northern Vietnam, near 23°North (Little, 2004). Type : Vietnam, Ha Giang Province, Quan Ba, Bat Dai Son, Bat Dai Son Provincial Protected Area, D.K. Harder et al. DKH 6091 (holo- type : HN; isotypes : K, LE, MO.). Paratypes: hoc. loc., D.K. Harder et al. DKH 6090 (MO); Can Ty, Sing Xuoi Ho, N. T. Hiep et al. NTH 3594 (MO, K)