Based on both morphological and molecular evidence, it is confirmed that Alseodaphnopsis maguanensis is conspecific with A. hokouensis. Hence, Alseodaphnopsis maguanensis is treated as a synonym of A. hokouensis here. The conservation status of Alseodaphnopsis hokouensis is also re-evaluated according to the IUCN Red List Categories and Criteria in this study.

Alseodaphnopsis, Lauraceae, morphology, phylogeny, synonym, taxonomy

As one of the largest basal angiosperm families, Lauraceae includes more than 50 genera and 2500 ~ 3000 species distributed in tropical and subtropical regions worldwide (Chanderbali et al. 2001). The delimitation, delineation and identification of Lauraceae species, especially for tropical species, are always complicated due to limited variation in floral and other morphological characters and insufficient specimen collection (van der Werff and Richter 1996; Rohwer 2000; Li and Li 2004; Yang and Liu 2015).

Alseodaphnopsis hokouensis (H. W. Li) H. W. Li & J. Li was first published as an Alseodaphne Nees species (Lee et al. 1979) and then it was transferred to Alseodaphnopsis H. W. Li & J. Li, a recently described genus of the Lauraceae (Mo et al. 2017). Since it was first collected in 1953, only three herbarium records (including two type specimens) of Alseodaphnopsis hokouensis can be found and no fruiting specimen has been collected.

During recent field surveys in SE Yunnan (SW China), some flowering and fruiting individuals of Alseodaphnopsis hokouensis were found and they resembled a recently-published Alseodaphnopsis species, A. maguanensis L. Li & J. Li (Li et al. 2020). Based on both morphological and molecular evidence, we confirm that Alseodaphnopsis maguanensis is conspecific with A. hokouensis. Therefore, we treat Alseodaphnopsis maguanensis as a synonym of A. hokouensis here. Based on the field survey data, we also re-evaluate the conservation status of Alseodaphnopsis hokouensis in this study.

During our field surveys in SE Yunnan, two populations of Alseodaphnopsis hokouensis were found in Huayudong and Qincaitang, Nanxi Town, Hekou County (Fig. 1), each with about 10 mature individuals. No individual was found at the type locality of Alseodaphnopsis hokouensis, Masike, Nanxi Town, Hekou County. Two populations of Alseodaphnopsis maguanensis, each with about 20 mature individuals, were also investigated in Gulinqing Provincial Natural Reserve (Maguan County) according to the work of Li et al. (2020).

Figure 1. 

The recorded localities of Alseodaphnopsis hokouensis and A. maguanensis in SE Yunnan, SW China.

The MP and BI analyses of the ITS + LEAFY intron II combined dataset generated congruent topologies. The Bayesian consensus tree with MP bootstrap (BS) and Bayesian posterior probability (PP) values is shown in Fig. 2. As in the work of Li et al. (2020), all Alseodaphnopsis specimens sampled in the present study formed a well-defined clade (BS 88%, PP 1.00). Within the Alseodaphnopsis clade, there are two well-supported subclades which consist of four and five species, respectively. All individuals of Alseodaphnopsis hokouensis and A. maguanensis formed a strongly-supported clade (BS 100%, PP 1.00), closely related to A. rugosa. Within this clade, the individuals of these two species are mixed with each other and their relationships are poorly resolved.

Figure 2. 

Bayesian consensus tree of ITS + LEAFY intron II combined dataset. MP bootstrap (BS ≥ 50%) and Bayesian posterior probability (PP ≥ 0.95) values are shown above branches. Act. = Actinodaphne, Al. = Alseodaphne, Als.= Alseodaphnopsis, Deh. = Dehaasia, Lin. = Lindera, Lit. = Litsea, Mac. = Machilus, Neo. = Neolitsea, Not. = Nothaphoebe, Pho. = Phoebe.

The morphological characters of Alseodaphnopsis hokouensis, A. maguanensis and closely related A. rugosa were compared in detail, based on the data from type specimens and protologues (Li et al. 2008; Li et al. 2020). Morphological comparisons showed that Alseodaphnopsis maguanensis is almost the same as A. hokouensis, except that the leaves of the former are oblong-obovate or oblong-oblanceolate and those of the latter are elliptic to oblong (Table 2). After carefully checking the specimens collected from field surveys, we found that the leaves of both species can vary from elliptic, oblong to oblong-obovate or oblong-oblanceolate (Fig. 3). They are usually oblong-obovate or oblong-oblanceolate and occasionally elliptic to oblong. According to the newly-obtained fruiting specimens of Alseodaphnopsis hokouensis, the fruit characters of Alseodaphnopsis hokouensis are also consistent with those of A. maguanensis (Fig. 3). Additionally, the phenologies and habitats of these two species are quite similar and their distribution areas are adjacent as well (Fig. 1).

Figure 3. 

Alseodaphnopsis hokouensis A flowering branchlet B fruiting branchlet C different shapes of leaf blades. Photographed by Lang Li.

To sum up, the results of both morphological comparison and phylogenetic analysis showed that Alseodaphnopsis maguanensis is conspecific with A. hokouensis. Therefore, we propose that Alseodaphnopsis maguanensis should be treated as a synonym of A. hokouensis. The insufficient specimen collection of Alseodaphnopsis hokouensis, especially the lack of fruiting specimens, hinders a comprehensive understanding of the species. The same situation is found in many other rare and endemic Lauraceae species in SE Yunnan, such as species of Alseodaphne, Beilschmiedia Nees, Caryodaphnopsis Airy Shaw, Cryptocarya R. Br., Endiandra R. Br., Machilus Rumph. ex Nees, Phoebe Nees and Syndiclis Hook. f., etc. (Li et al. 2008). Thus, more field surveys and specimen collections are suggested in SE Yunnan in order to improve the understanding of these rare and endemic Lauraceae species.

Taxonomic treatment

 Alseodaphnopsis hokouensis (H. W. Li) H. W. Li & J. Li

Alseodaphne hokouensis H. W. Li, Act Phytotax. Sin. 17 (2): 71. 1979. Basionym. Type: CHINA. Yunnan Province: Hekou County, 10 May 1953, K. H. Tsai 1039 (holotype: KUN [KUN0047456!]; isotype: KUN [KUN0108581!]).

= Alseodaphnopsis maguanensis L. Li & J. Li, PhytoKeys 138: 27–39. 2020. syn. nov. Type: CHINA. Yunnan Province: Maguan County, 14 May 2016, Lang Li et al. GLQ26 (holotype: HITBC!).

Revised description

Trees evergreen, up to 20 m tall. Branchlets terete, 3–6 mm in diameter, greyish, striate, glabrous, with lenticels and leaf scars. Terminal buds subglobose, ca. 2 mm in diameter; bud scales broadly ovate, acute at apex, glabrous. Leaves clustered at apex of branchlet, alternate or subverticillate; petiole robust, 2–3 mm thick, 1.5–3 cm long, concave-convex; leaf blade green adaxially, glaucous abaxially when young, but green or pale green when mature, oblong-obovate or oblong-oblanceolate, sometimes elliptic to oblong, 10.5–32 × 3.5–9 cm, subleathery to leathery, glabrous on both surfaces, mid-rib elevated abaxially, impressed adaxially, lateral veins 8–13 pairs, slightly elevated on both surfaces, oblique, evanescent and interconnected near leaf margin, transverse veins and veinlets densely reticulate, conspicuous on both surfaces when dry, base cuneate to broadly cuneate, apex shortly acuminate, sometimes abruptly shortly acuminate. Panicles subterminal, clustered at apex of branchlet, 10.5–20 cm, many-flowered; peduncle branched at middle or above, peduncle and rachis glabrous; bracts and bracteoles linear, ca. 1.5 mm, acute, ciliate, caducous. Pedicels slender, 3–8 mm, slightly dilated on top, glabrous. Flowers small, ca. 2.5 mm. Perianth tube short; perianth lobes 6, broadly ovate, slightly acute, glabrous outside, pubescent inside, subequal, outer ones ca. 2 × 1.5 mm, inner ones ca. 2.5 × 2 mm, deciduous. Fertile stamens 9, minute, 1.5–2 mm in 1^st and 2^nd whorls, 1.7–2.2 mm in 3^rd whorl; filaments villous, 0.7–1 mm in 1^st and 2^nd whorls, 1–1.2 mm in 3^rd whorl, those of 3^rd whorl each with 2 shortly stalked orbicular-cordate glands at base, others glandless; anthers of 1^st and 2^nd whorls ovate, almost as long as filaments, with introrse cells, those of 3^rd whorl elliptic, slightly shorter than filaments, with extrorse cells. Staminodes conspicuous, ca. 1.5 mm, sagittate, stalked. Ovary ovoid, 1.2–1.5 mm, glabrous, attenuate into a 0.5–0.8 mm long style; stigma discoid, inconspicuous. Infructescence subterminal, 10–18 cm, robust, glabrous, with one or two well-developed fruits. Fruit oblate, 4–5 × 5–6 cm, immature fruit green, brown when mature, fruit stalk robust, 3–4 mm in diameter, apex dilated, 5–10 mm in diameter, sometimes nearly cylindrical, fleshy and warty when fresh.

Phenology

Flowering from May to June and fruiting from July to September.

Distribution and habitat

Hekou County and Maguan County, Yunnan Province, China. Tropical limestone forests in valleys, usually near streams, at an elevation of 150–850 m.

Conservation status

Currently, Alseodaphnopsis hokouensis is known from Hekou Country and Maguan Country (Yunnan Province, China) with four populations (Fig. 1). Two populations found in Maguan Country are all located in Gulinqing Provincial Nature Reserve, each with about 20 mature individuals (Fig. 4). The other two populations found in Hekou Country, each with about 10 mature individuals, are not located in any nature reserve and those individuals mostly occur on the roadsides or in strongly-disturbed forests near the villages (Fig. 4). No individual was found at the type locality, Masike, Nanxi Town, Hekou County. According to the IUCN Red List Categories and Criteria version 15.1 (July 2022), the conservation status of Alseodaphnopsis hokouensis is re-evaluated as Critically Endangered (CR, C2a(i)).

Figure 4. 

Different habitats of Alseodaphnopsis hokouensis A in the forest of the Nature Reserve B on the roadside C in the strongly disturbed forest near the village.

Additional specimens examined

China. Yunnan Province: Hekou County, 17 June 2020, Lang Li et al. 2020064 (HITBC); 18 June 2020, Lang Li et al. 2020071 & 2020072 (HITBC); 25 August 2020, Lang Li and Guan-long Cao, 2020135, 2020136, 2020137 & 2020138 (HITBC). 13 May 2022, Lang Li and Dian-yang Zou, 2022027 (HITBC). Maguan County, 19 June 2020, Lang Li et al. 2020082, 2020083 & 2020086 (HITBC); 20 June 2020, Lang Li et al. 2020091, 2020092, 2020093, 2020094, 2020095 & 2020096 (HITBC); 24 August 2020, Lang Li and Guan-long Cao, 2020127 & 2020128 (HITBC); 2 August 2022, Lang Li et al. 2022034, 2022035 & 2022036 (HITBC).

The authors are grateful to Xi-bing Guo and Jin-guo Zhang for their kind help during the field surveys and to Jens G. Rohwer for his valuable comments on the manuscript.