A new species of Amentotaxus (Taxaceae) from China, Vietnam, and Laos

Abstract

A new species Amentotaxus hekouensis L.M. Gao is described as new to science from Hekou, Yunnan of China, Lao Cai of Vietnam and Xiang Khouang of Laos. The new species is similar to A. argotaenia (Hance) Pilg. in linear or linear-lanceolate leaves, stomatal bands white and microsporophylls 6–8, each with 4–6 pollen sacs, but differs from the latter by its larger leaf size with 8–12.5 cm × 0.9–1.4 cm (vs. 2–11 cm × 0.5–1.1 cm in A. argotaenia), long acuminate leaf apex (vs. rounded to sharply triangular in A. argotaenia), stomatal bands with 25–30 rows (vs. 15–25 rows in A. argotaenia), stomatal bands equal to or slightly narrower than marginal bands (vs. narrower than marginal bands in A. argotaenia); pollen-cone racemes borne 1–2 (vs. 2–4 (10) in A. argotaenia), cones in 12–16 pairs (vs. ca. 12 pairs in A. argotaenia). Its distinctive nature has also been confirmed through DNA barcoding analysis of this genus. The new species is provisionally assessed as endangered (EN) due to its restricted distribution, small population size and the prevalence of habitat destruction within its range.