﻿Endiandramacrocarpa (Lauraceae), a new tree species from south-western China

﻿Abstract Endiandramacrocarpa, a new species of Endiandra (Lauraceae) from Yunnan Province of south-western China, is here described and illustrated, based on morphological evidence. Compared to other Endiandra species occurring in south China and the adjacent regions in Indochina, this species is mainly characterised by its much larger ellipsoidal fruits (up to 11 × 6 cm), as well as glabrous branchlets and puberulent inflorescences.


Introduction
The genus Endiandra R. Br. of the Lauraceae family is widely distributed from south China, Indochina, Malesia and Australia to the Pacific Islands (Rohwer 1993;Arifiani 2001;van der Werff 2001). It has approximately 100 species and its diversity is strongly centred in south-eastern Malesia and Australia (Hyland 1989;Arifiani 2001;Cussan et al. 2007). Endiandra was first described by Brown (1810), based on the type species from Australia, Endiandra glauca. The species of the genus can be characterised by alternate, penninerved leaves; axillary or terminal panicles; bisexual flowers with three 2-celled fertile stamens and unprotected fruits on pedicels (Kostermans 1957;Rohwer 1993;van der Werff 2001;Cussan et al. 2007;Li et al. 2008).
According to previous studies of wood and bark anatomy, floral morphology, taxonomy and molecular phylogeny, Endiandra belongs to the basal lineages of the family, in the tribe Cryptocaryeae or the Cryptocarya group and is closely related to Beilschmiedia Nees (Richter 1981;Rohwer 1993;van der Werff and Richter 1996;Rohwer 2000;Chanderbali et al. 2001;Rohwer and Rudolph 2005;Rohwer et al. 2014;Li et al. 2020;Song et al. 2020). Vegetatively, Endiandra is very similar to Beilschmiedia, only flower characters can differentiate the two genera (van der Werff 2001; Arifiani et al. 2012). Typical flowers of Endiandra only have three fertile stamens in the third whorl, whereas Beilschmiedia has nine fertile stamens (Arifiani 2001;van der Werff 2001;Arifiani et al. 2012).
Without any comprehensive revision, Endiandra has so far only been treated in floras or local revisions (e.g. Hyland (1989); Kochummen (1989); Arifiani (2001); Cussan et al. (2007); Li et al. (2008)). In China, there are only three recognised Endiandra species (two endemic) and they are distributed in Yunnan, Guangxi, Hainan and Taiwan (Li et al. 1979;Li et al. 1982;Liang et al. 1985;Li et al. 2008;Yang and Da 2008;Yu et al. 2009). During recent field surveys in south-eastern Yunnan Province, we collected an unknown Lauraceae species with very large fruits. Further morphological study suggests that this species belongs to Endiandra and differs from its other species distributed in south China and the adjacent regions. As a result, we here describe this species as new to science.

Taxonomic treatment
Phenology. Flowering from April to May and fruiting from July to October. Distribution and habitat. Currently known only from the type locality in Maguan County, Yunnan Province, south-western China (Fig. 3). Tropical montane forest in valley, on clay loam soil mixed limestone; ca. 800 m a.s.l.
Etymology. The specific epithet "macrocarpa" of the new species refers to its very large fruits compared to the other species within the genus Endiandra.
Preliminary conservation status. Currently, E. macrocarpa is only known from the type locality in Maguan County, Yunnan Province, south-western China with only one mature individual. It is located in tropical montane forest near the village, which is strongly disturbed by human activities. So far, no other occurrence of this species in south-eastern Yunnan and the adjacent regions has been found or reported. Further in-depth field surveys are suggested in order to find more individuals and locations of

Discussion
South-eastern Yunnan is biogeographically located in a transitional zone from tropical Southeast Asia to subtropical East Asia (Zhu and Yan 2009). The flora of this region is suggested to be a marginal part of the tropical Asian flora, but contains more subtropical and temperate elements than other floras of the adjacent regions, for example, southern Yunnan, south-western Guangxi and northern Vietnam (Zhu and Yan 2009;Zhu 2013). As one of the world's biodiversity hotspots, south-eastern Yunnan is of extreme interest to botanists not only for its richness of primitive angiosperm taxa, such as species of Lauraceae and Magnoliaceae, but also for being a centre of plant endemism in China (Myers et al. 2000 (Liu et al. 2013aYang et al. 2021).
Far away from its diversity centre in the south-eastern part of Malesia and Australia, Endiandra species are very rare in China. Besides the newly-discovered E. macrocarpa, only three recognised Endiandra species (two endemic) are distributed in Yunnan, Guangxi, Hainan and Taiwan (Li et al. 2008 , Fig. 3). Considering the possible endemism of the new species, we firstly compared E. macrocarpa with the other three Endiandra species occurring in China, which possess much smaller fruits (detailed in Table 1). Fruits of E. coriacea Merr. are ovoid, up to 2 × 1 cm. Fruits of E. hainanensis Merr. et F.P. Metcalf ex Allen are narrowly ellipsoid, up to 3.8 × 1.4 cm. Fruits of E. dolichocarpa S. Lee et Y. T. Wei are cylindrical and larger, up to 8 × 2.3 cm, but still much smaller than the fruits of E. macrocarpa. Additionally, E. macrocarpa has glabrous branchlets and puberulent inflorescences, while twigs are puberulent in E. coriacea and panicles are glabrous in E. hainanensis (Li et al. 2008). We also compared E. macrocarpa with three other Endiandra species occurring in the adjacent regions of south-eastern Yunnan in Indochina, for example, Vietnam, Laos and Thailand (detailed in Table 1). Endiandra firma Nees differs from E. macrocarpa by its smaller fruits with rounded tips (Hooker 1875). Endiandra macrophylla (Blume) Boerl. differs from E. macrocarpa by its smaller fruits and much larger leaves (Arifiani 2001). Endiandra rubescens Blume ex Miq. differs from E. macrocarpa by its smaller fruits and pubescent branchlets (Arifiani 2001). Species with giant fruits are uncommon in Endiandra. Endiandra insignis (F.M.Byailey) F.M.Byailey and E. sulavesiana Kosterm., endemic to Australia and Sulawesi, respectively, are the two Endiandra species that possess fruits with comparable size to those of E. macrocarpa (Kostermans 1955;Cussan et al. 2007). However, other fruit characters of these two species are quite different. Endiandra insignis has globular, ribbed fruits (6-8 × 6.5-10.1 cm) and E. sulavesiana has long cylindrical, ribbed fruits (up to 13 × 2.5 cm), while E. macrocarpa has ellipsoidal, smooth fruits (up to 11 × 6 cm). As a result, morphological evidence supports the recognition of E. macrocarpa as a distinct species in the genus Endiandra.