台灣穗花杉 (tai wan sui hua shan) [Chinese], Taiwan catkin yew.
Trees to 10 m tall and 30 cm dbh, sparsely branched. Bark smooth, brown, exfoliating thin flakes. Twigs opposite, with grooves running from one leaf to the next, green in first year, later yellowing to brown. Leaves coriaceous, lanceolate, falcate, margins revolute; dark green with a midrib above; two broad whitish stomatal bands flanking a midrib below; 5-8.5 cm × 7-8 mm broad; apex acuminate. Pollen cones axillary or subterminal in clusters of 2-5 racemes, each 1.5-3.5 cm long with 7-10 crowded pairs of 2.5 mm long cones. Seed-bearing structures axillary near shoot ends, with 1.5-2 cm long peduncles, ellipsoid, with 8-10 decussate keeled bracts enclosing 20-25 × 9-11 mm aril, green maturing reddish purple, apex mucronate, with a single seed 15×7 mm. 2n=14 (Huang 1994, Farjon 2010).
Compared to A. argotaenia, A. formosana has leaves about the same width, but with stomatal bands about twice as wide and green leaf margins accordingly much narrower. Also, A. formosana has about as many pollen cones but on shorter racemes, so its racemes have less space between cones (Farjon 2010).
Taiwan, in the SE at 1,200-1,300 m elevation, as an understory tree in montane evergreen tropical rainforest and broadleaf subtropical forest, sometimes with Podocarpus nakaii (Huang 1994, Farjon 2010). In the Dawu Taiwan Amentotaxus Nature Reserve it occurs in subtropical broadleaf evergreen forest developed on sandstone and shale. The average annual temperature is 16°C, ranging from 10°C in the coldest month to 20°C in the warmest. Annual rainfall is 2,500-3,000 mm, summer-wet. Winters are also damp, producing a perennially warm and humid climate. Dominant species in this forest include Machilus thunbergii, Castanopsis cuspidata var. carlesii, Trochodendron aralioides, Engelhardtia roxburghiana, Beilschmiedia erythrophloia, Machilus konishi, Alnus formosanai, Syzygium tripinnatum, and Machilus japonica (Taiwan Forestry Bureau 2005).
Hardy to Zone 9 (cold hardiness limit between -6.6°C and -1.1°C) (Bannister and Neuner 2001).
The IUCN reports that as of 2000, this species is only known from four localities in cloud forest in the Hengchan Peninsula: Tawu, Kutzulunshan, Chachayalaishan and Lilungshan. At that time, all individuals were thought to represent a single population containing no more than 250 mature plants. This assessment was updated by Farjon (2010) who noted the extreme practical difficulty involved in locating the plants, suggesting that the real population is larger; and who also notes that it "has recently been found in 'new' localities" and that the principal threat to its continued existence is conversion of its habitat to Cryptomeria japonica plantations. It may thus be reevaluated as "Endangered" per IUCN criteria.
There are very few data. The Taiwan Forestry Bureau (2005) reports trees of up to 36 cm dbh.
(a) Pingtung Xian: Chunji Xiang: Chachayalaishan Nature Preserve Area. Elevation:1000-1100 m. In coniferous forest.
(b) Pingtung Xian: Chunji Xiang: Chachayalaishan, protection area, 29th compartment. Elevation:1000-1200 m. Tree ca. 3m tall, DBH 5 cm; scattered in forest, on muddy slope; only find 10 sapling in this habitat.
(c) Pingtung Xian: Tahanshan, Amentotaxus formosana Preserve Area. Elevation:1300-1500 m. Tree ca. 2-6 m high.
Li Hui-Lin. 1952. A taxonomic review of the genus Amentotaxus. Journal of the Arnold Arboretum 33:192-198. This publication is available online at botanicus.org.
Taiwan Forestry Bureau. 2005. Dawu Taiwan Amentotaxus Nature Reserve. http://conservation.forest.gov.tw/ct.asp?xItem=22263&ctNode=725&mp=11, accessed 2008.03.12.
Last Modified 2014-03-29