Phoebe jinpingensis Bing Liu, Y.Yang, W.Y.Jin & Zhi Yang, 2021

Yang, Zhi, Jin, Wei-Yin, Liu, Bing, Ferguson, David Kay & Yang, Yong, 2021, Big fruits with tiny tepals: An unusual new species of Lauraceae from southwestern China, PhytoKeys 179, pp. 129-143 : 129

Phoebe jinpingensis Bing Liu, Y.Yang, W.Y.Jin & Zhi Yang sp. nov.

Figs 1 , 2 , 3

Type.

China. Yunnan Province: Jinping County, Mengla, Tuomazhai , 22°37'N, 103°01'E, elev. 956 m, 8 Apr 2014, B.Liu, Y.Yang, Q.W.Lin, L.Jiang & X.J.Li 2050 (holotype: PE!; isotypes: PE!) .

Diagnosis.

This species is similar to P. macrocarpa C.Y.Wu ( Wu and Wang 1957) and P. megacalyx H.W.Li ( Lee et al. 1979) in the large fruits over 3 cm in diam., but differs from the latter two species by the subglabrous leaves being more or less oblong-elliptic and the larger fruits having smaller tepals.

Description.

Trees (Fig. 1A ), up to 15 m tall, to 40 cm in DBH (diameter at breast height). Bark yellowish gray. Branchlets purplish, slender, longitudinally ridged, subglabrous. Leaves alternate, usually clustered at the apex of branchlets, thinly coriaceous to chartaceous, subglabrous, oblong to oblanceolate (Fig. 1B ), 15-25 × 5-8 cm, apex acute to slightly acuminate, base acute, midvein impressed adaxially, and prominently elevated abaxially, lateral (secondary) veins 7-10 pairs, immersed adaxially and elevated abaxially, transverse minor (tertiary) veinlets connecting lateral veins visible; petioles 1.2-4 cm, subglabrous. Panicles slender, 4-9 cm long, subglabrous. Flowers yellowish (Fig. 1C ). Tepals subequal, 2-2.4 mm long. Fertile stamens in three whorls; filaments of the first and second whorls 1-2 mm; anthers 4-locular, locules arranged in trapezoid shape; each filament of the 3rd staminal whorl possessing two yellow cordate glands at its base. Staminodes sagittate. Fruits ellipsoid to obovoid, avocado-shaped, 5-8 cm long, and 3.5-5.2 cm in diam. (Fig. 1D-F ); tepals persistent, equal, triangular to ovate, tiny, 2-2.5 mm long, clasping the fruit base (Fig. 1F ), concealed and inconspicuous when fruit becoming swollen (Fig. 1E ). Fruit peduncles not thickened.

Distribution.

So far, this species has only been found in southeastern Yunnan, China (Fig. 4 ).

Habitat.

This species occurs in montane evergreen forests at an altitudinal range of 900-980 m. It blooms in April, and the fruits mature from September to December.

Etymology.

The specific epithet ' Phoebe jinpingensis ' refers to the type locality "Jinping County".

Additional specimens examined.

China. Yunnan Province: Jinping County, Mengla, Tuomazhai, 8 Apr 2014, fruit, B.Liu, Y.Yang, Q.W.Lin, L.Jiang & X.J.Li 2052 (PE!); Jinping County, Mengla, Tuomazhai, 9 Oct 2011, fruit, B.Liu 1477 (PE!); Jinping County , Mengla, Tuomazhai, 14 Sep 2014, fruit, B.Liu, Y.Song, H.Lai & X.Yao 2417 (PE!) .

Conservation.

There is only one population with 10 mature individuals occupying ca. 400 m2. Fewer than 10 juvenile individuals were found. All the individuals have not been protected in any nature reserve, and a rubber plantation exists nearby the population. Based on IUCN Red List Categories and Criteria ( IUCN 2012), the new species is categorized as "Critically Endangered" (CR Blab (v); D).

Phylogeny

We finally obtained 30 sequences of nrITS, 27 sequences of LEAFY and 30 sequences of mat K (Table 2 ). The aligned nrITS sequences had 745 nucleotides including 149 variable sites among which 98 sites are parsimony-informative. The aligned LEAF sequences consisted of 896 nucleotides including 158 variable sites and 57 parsimony-informative. The aligned mat K sequences contained 763 nucleotides with 22 variable sites and 13 parsimony-informative sites. The concatenated matrix was 2404 nucleotides in length and included 329 variable sites and 168 parsimony-informative sites. The best-fit nucleotide substitution models for the three markers for both BI and ML analyses are listed in Table 3 .

Our phylogenetic study gave rise to BI and ML trees showing similar topology (Figs 5 , 6 ). The genus Phoebe constituted a clade with moderate to high support (BS: 75, PP: 0.91), the two clades within the genus were robustly supported (BS: 100 and PP: 1). Clade I consisted of P. puwenensis W.C.Cheng ( Cheng et al. 1963), P. macrocarpa , P. megacalyx , and P. jinpingensis . The four samples of our new species fell within a robust clade (BS: 100, PP: 1). Clade II includes P. angustifolia Meisn. ( Meissner 1864), P. cavaleriei (H. Lév.) Y.Yang & Bing Liu ( Yang and Liu 2015), P. chekiangensis C.B.Shang ( Shang 1974), P. formosana (Hayata) Hayata ( Hayata 1915), P. lanceolata (Wall. ex Nees) Nees ( Nees von Esenbeck 1836), P. nanmu (Oliv.) Gamble ( Sargent 1914), P. neurantha (Hemsl.) Gamble ( Sargent 1914), P. sheareri (Hemsl.) Gamble ( Sargent 1914), and P. tavoyana (Meisn.) Hook.f. ( Hooker 1886).

Machilus was monophyletic (BS: 100 and PP: 1). Alseodaphne huanglianshanensis H.W.Li & Y.M.Shui ( Li and Shui 2004) and Dehaasia incrassata (Jack) Kosterm. ( Kostermans 1952) were close to Machilus (BS: 59%, PP: 0.91), but relationships among them were not resolved. Alseodaphnopsis , a recently established genus, constituted a monophyletic group which received high support (BS: 84%, PP: 1). Relationships among Alseodaphnopsis , Phoebe , and Machilus - Dehaasia - Alseodaphne were ambiguous.

Figures

Figure 1. Morphology of Phoebe jinpingensis sp. nov. A habit of the tree B flowering branches C portion of a branch bearing inflorescences D fruiting branches E two fruits displaying swollen base and inconspicuous tepals F a fruit displaying the tiny tepals at the base.

Figure 2. Anatomy of a flower of Phoebe jinpingensis sp. nov. showing morphology of stamens, staminodes, and pistil A stamens of the first staminal whorl, adaxial side B stamen of the first staminal whorl, abaxial side C stamen of the second staminal whorl, adaxial side D stamen of the second staminal whorl, abaxial side E stamen of the third staminal whorl, adaxial side F stamen of the third staminal whorl, abaxial side G staminode of the fourth staminal whorl, adaxial side H staminode of the fourth staminal whorl, abaxial side I pistil.

Figure 3. Line-drawing showing details of Phoebe jinpingensis sp. nov. A a flowering branch B fruits C fertile stamens of the first staminal whorl, abaxial side D fertile stamens of the first staminal whorl, adaxial side E fertile stamen of the third staminal whorl with the two glands at the base of the filaments, adaxial side F fertile stamen of the third staminal whorl with the two glands at the base of the filaments, abaxial side G staminode of the fourth staminal whorl showing pubescence, abaxial side H staminode of the fourth staminal whorl showing pubescence, adaxial side I pistil, with obovoid pubescent ovary and linear style.

Figure 4. A map showing the distribution of Phoebe jinpingensis sp. nov.

Figure 5. Maximum Likelihood tree based on nrITS, LEAFY and plastid mat K indicating the phylogenetic position of Phoebe jinpingensis sp. nov. Bootstrap support values (> 50 %) are shown above the branches.

Figure 6. Bayesian tree based on nrITS, LEAFY and plastid mat K showing phylogenetic position of Phoebe jinpingensis sp. nov. Bayesian posterior probabilities (> 0.50) are indicated above the branches.