Amentotaxus hatuyenensis / Hà Tuyên catkin-yew

Amentotaxus hatuyenensis first described in 1996 by Tiên Hiêp Nguyên in Flore du Cambodge du Laos et du Vietnam, 28th edition, is commonly know as Hà Tuyên catkin-yew; as well as Dẻ tùng sọc nâu rộng, Sam bông sọc nâu rộng in the Vietnamese language. The species name refers to Hà Tuyên, a province in northern Vietnam, which contained the type locality. Hà Tuyên province was subdivided in 1992, and the known distribution of this species is now in Hà Giang province.

Description. Hà Tuyên catkin-yew is an evergreen coniferous species of shrubby tree that grows to mature heights of 65 feet (20 m) tall with a trunk up to 10 inches (25 cm) in diameter, measured at breast height. Descriptions are virtually the same as for A. yunnanensis, with the following differences.

• Branches are thin and erect, forming a wide, ovate crown.
• Leaves are similar, but spread from the shoot at a more obtuse angle, 70 to 90° rather than 50 to 70°.
• Pollen cones are borne in 10 to 15 pairs on circa 4 inch (10 cm) long racemes, instead of in 12 to 20 pairs on 4 to 6 inch (10 - 15 cm) long racemes.

Distribution. This species is native to northern Vietnam's Hà Giang province, where it grows on steep limestone karst mountains at elevations of 3.300 to 5,000 feet (1,000 - 1,500 m) above sea level, with frequent fog and annual precipitation of about 70 inches (1,800 mm), and year-round temperatures of 60 to 65°F (15 - 18°C). It grows with conifers including Amentotaxus yunnanensis, Cephalotaxus mannii, Cupressus vietnamensis, Pinus fenzeliana, Tsuga chinensis, Nageia fleuryi, Podocarpus neriifolius, and Podocarpus pilgeri, as well as with various angiosperm trees and a rich epiphytic flora.

Hardy to USDA Zone 9, cold hardiness limit between 20° and 30°F (-6.6° and -1.1°C).

A. hatuyenensis faces a high risk of extinction in the wild due to habitat loss (Hiep 2004). It is known from only a few locations but overall its status and distribution appear to still be poorly known.

Attribution from: Aljos Farjon; A Handbook of the World's Conifers; ©2010, Brill Academic Publishers, Leiden, The Netherlands.