Cephalotaxus hainanensis

H.L. Li 1953

Common names

Hainan plum-yew, 海南粗榧 hǎi nán cū fěi [Chinese].

Taxonomic notes

Type: China, Hainan, Wuzhishan City, Fanyang Township (Fan Yah), elev. 3500 ft, 1932–1933, N. K. Chun and C. L. Tso 44183, holotype US. Syn. Cephalotaxus sinensis subsp. hainanensis (H.L.Li) Silba 2007. During the long history of confusion about species delimitation in this genus (see Cephalotaxus), various authors recognized a close similarity to C. mannii and some treated the taxa as synonymous. Genome sequencing has now revealed this to be a Hainan endemic, sister to C. mannii in a clade with C. lanceolata (Wang et al. 2022).

Description

Trees to 20 m tall and 70 cm dbh, with a rounded or narrow crown of spreading and ascending branches. Bark thin, exfoliating in flakes and strips, brown weathering gray. Twigs up to 15 cm long, slender, grooved between decurrent leaf bases, green maturing orange-brown. Leaves in two pectinate rows, spreading horizontally, diverging at 45-80° to twig axis, subopposite, 20-40 × 2.5-4 mm, slightly falcate, flat, nearly sessile, linear, broadly obtuse with a mucronate apex; upper (adaxial) midrib thin, prominent, continuous, 0.3 mm wide; lower midrib conspicuous but more flattened; color dark green or olive-green on upper side, bearing two pale stomatal bands on lower side, stomatal bands each with ca. 20 intermittent lines bordered by slightly revolute leaf margins. Pollen cones axillary, in rows of capitula on the underside of lateral foliage twigs, each capitulum on a 3-5 mm long scaly peduncle subtended by ovate, incurved bracts with more or less hyaline margins, bearing 6-8 small, globose, sessile, pale yellow cones up to 4 mm diameter. Microsporophylls 6-12 per cone, each with 3-4 globose, cream-colored pollen sacs. Seeds cones solitary at base of lateral foliage twigs on 4-10 mm long peduncles; fertilized ovules surrounded by an ellipsoid green aril enclosing the seed; at maturity 20-30 × 10-15 mm, soft, red with longitudinal striations. Seed (ob)ovoid, sometimes laterally compressed, 18-28 × 8-14 mm, apex mucronate or cuspidate (Farjon 2010).

Distribution and Ecology

China: Endemic to central Hainan Island, where there are only 5 georeferenced records (as of mid-2024). Habitat is mixed warm temperate/subtropical mountain rainforests at elevations of up to 1700 m. In these forests the species attains tree habit and size, 10-20 m tall (Farjon 2010). The area has a tropical marine monsoon climate with distinct dry and wet seasons, an average annual rainfall of 1759 mm, and an average annual temperature of 22.5-26.0°C. Forest composition includes at least 105 tree species belonging to 78 genera and 44 families, of which the only conifers are Torreya grandis and an unspecified species of Podocarpus (Wang et al. 2023). Hardy to Zone 9 (cold hardiness limit between -6.6°C and -1.1°C) (Tripp 1995, Bannister and Neuner 2001).

Distribution data (C. hainanensis shown in red), based on GBIF occurrence download https://doi.org/10.15468/dl.bz6u39 (2024.08.24). Open left pane for legend; click on any icon for a link to source information. See map notes (left pane) for details on map preparation.

Cephalotaxus hainanensis is listed as "Endangered" due to a small area of occupancy a small area of occupancy (100-500 km²) and a continuing decline in the extent and quality of the habitat due to the expansion of tourist developments on the island. The population is estimated to number 126,000 individuals in 4 or 5 locations. In the past, it was harvested for timber and the bark was also stripped, but it is not known to what degree those threats impacted the population. The species occurs in some protected areas (e.g. the Wuzhi Shan, Bawang Ling, and Diao Luo Shan nature reserves), and the Chinese Government has imposed a ban on all logging (Yang and Liao 2013). This assessment dates to 2010 and development since then has likely caused further losses.

Remarkable Specimens

No data as of 2024.08.25, but based on reported sizes, this achieves larger sizes than any other species of Cephalotaxus except C. harringtonia.

Ethnobotany

The species was formerly harvested for timber, but logging is now banned. Bark and foliage stripping still occurs to collect the valuable medicinal extracts, cephalotaxine and harringtonine (Yang and Liao 2013). These alkaloids (which occur in a number of species of Cephalotaxus) were found in the early 1970s to be effective against certain types of cancer, and are now employed in treatment of several types of leukemia (Srivastava and Raghuwanshi 2021).

Observations

Wang et al. (2023) performed their research in the Hainan Tropical Rainforest National Park, which seems like a suitable place to search for it. The species is also reported to occur in the Wuzhi Shan, Bawang Ling, and Diao Luo Shan nature reserves (Yang and Liao 2013).

Remarks

The epithet refers to Hainan Island in China.

Citations

Li, H. L. 1953. New species and varieties in Cephalotaxus. Lloydia 16(3):162-164.

Srivastava, Akanksha, and Richa Raghuwanshi. 2021. Landscape of Natural Product Diversity in Land-Plants as Source for Anticancer Molecules. Pp. 233-254 in Evolutionary Diversity as a Source for Anticancer Molecules, edited by Akhileshwar Kumar Srivastava, Vinod Kumar Kannaujiya, Rajesh Kumar Singh, and Divya Singh. Academic Press. https://doi.org/10.1016/B978-0-12-821710-8.00010-2.

Wang, Jie, Chao-Nan Fu, Zhi-Qiong Mo, Michael Möller, Jun-Bo Yang, Zhi-Rong Zhang, De-Zhu Li, and Lian-Ming Gao. 2022. Testing the Complete Plastome for Species Discrimination, Cryptic Species Discovery and Phylogenetic Resolution in Cephalotaxus (Cephalotaxaceae). Frontiers in Plant Science 13: 768810. https://doi.org/10.3389/fpls.2022.768810, accessed 2024.08.26.

Wang, Ru, Shouqian Nong, Wencheng Peng, Biao Wu, Jia Yang, and Liguo Liao. 2023. Tree species composition and interspecific associations of rare and endangered plant Cephalotaxus hainanensis community. Ecology and Environment 32(10):1741.

Yang, Y. and W. Liao. 2013. Cephalotaxus hainanensis. The IUCN Red List of Threatened Species 2013: e.T34065A2842288. https://dx.doi.org/10.2305/IUCN.UK.2013-1.RLTS.T34065A2842288.en, accessed 2024.08.24.

See also

The species account at Threatened Conifers of the World.

Qio, F., Y-D He, Y-H Zhang et al. 2023. Elucidation of the 1-phenethylisoquinoline pathway from an endemic conifer Cephalotaxus hainanensis. Proceedings of the National Academy of Sciences 120(1):e2209339120.