Callicarpa yongshunensis Wen B. Xu, Xiao D. Li & Yan Ling Liu, sp nov.

Xu, Wen-Bin, Li, Xiao-Dong, Wang, Shu-Hui, Liu, Ang & Liu, Yan-Ling, 2024, Callicarpa yongshunensis (Lamiaceae): A new species from Hunan, China, PhytoKeys 241, pp. 131-141 : 131

Callicarpa yongshunensis Wen B. Xu, Xiao D. Li & Yan Ling Liu, sp nov.

Figs 1 , 2

Type.

China. Hunan Province, Yongshun County, Shanmuhe Forestry Farm , growing under the forest by the edge of a valley, 29.16517°N, 109.84132°E, 676 m alt., 16 March 2023 (fr.), W.B. Xu & X.W. Li 230155 (holotype: HIB, barcode no. 0250267, isotype: HIB, barcode no. 0250265) .

Diagnosis.

C. yongshunensis is morphologically similar to C. luteopunctata H.T. Chang, C. giraldii Hesse ex Rehd. and C. longifolia Lamk. (Table 2 ), but differs from C. luteopunctata in and C. giraldii in being a procumbent shrub (vs. erect shrubs) with evergreen leaf (vs. deciduous leaf) and white fruit (vs. red or purple fruit). Similarly, unlike C. longifolia , it has procumbent shrubs (vs. erect shrubs), no transverse scar in the nodes (vs. nodes with a transverse scar) and glabrous mature fruits covered with yellow glands (vs. mature fruit covered with stellate pubescence).

Description.

Procumbent shrub without an obvious main stem, up to 1.3 m high, branches slender, often base close to the ground and apex rising, sometimes roots growing from nodes when the nodes reaching the ground, nodes without transverse scar. Branchlets slightly 4-angled, densely covered with yellowish-brown stellate indumentum and yellow glands. Leaf with petiole 1.5-2.5 cm long, blade ovate-elliptic to oblong-elliptic, 7.5-16 × 3.5-5.5 cm, base narrowly cuneate and decurrent, margin serrate, apex acuminate, both surfaces subglabrous (with occasional hairs) and densely covered with small yellowish glands. Cymes 2-3 cm in diameter, 4-5-bifurcated, densely covered with stellate hairs and yellow glands; peduncle 4-7 mm. Calyx cup-shaped, 0.6-0.7 mm long, glabrous, sparsely yellow glandular, margin obscurely dentate and apex subtruncate. Corolla light red to light purple, 1.1-1.4 mm long, petals 4, elliptical, glabrous, slightly covered yellow glands outside. Stamens strongly exserted, usually twice as long as corolla. Style nearly as long as stamens, stigma bifid. Fruit white, 1.7-2.2 mm in diam., glabrous with sparsely yellow glands.

Distribution and habitat.

Currently, C. yongshunensis has been found in Yongshun and Shimen Counties in Hunan Province, China. It occurs in forests with weak light, at an elevation of 600-680 m. The companion species mainly include Litsea elongata (Wall. ex Nees) Benth. et Hook. f., Camellia costei Levl., Camellia oleifera Abel., Dichroa febrifuga Lour., Maesa japonica (Thunb.) Moritzi. ex Zoll. and Monachosorum henryi Christ.

Phenology.

Flowers in cultivated plants at the Wuhan Botanical Garden appeared between May and July, while fruits were observed in both wild and cultivated plants at the Botanical Garden from October to March of the following year.

Etymology.

The type specimen of this species was collected from Yongshun County, Hunan Province. Thus, we chose the specific epithet " Callicarpa yongshunensis " for this species. Its Chinese name is “永顺紫珠”.

Conservation assessment.

The on-going field investigation only identified few populations within narrow altitude ranges. More fieldwork is still warranted to better understand this taxon. According to the guidelines of IUCN Red List Categories and Criteria ( IUCN Standards and Petitions Committee 2022), C. yongshunensis is assessed as data deficient (DD).

Additional specimens examined.

C. yongshunensis (Paratypes): China. Hunan Province: Shimen County, Hupingshan National Nature Reserve, Xiahuanglian River , growing by the stream in the valley, 603 m alt., 20 December 2023 (fr.), Zhenfa Chen 231202 (HIB, barcode nos. 0250264 & 0250266, CSFI, barcode no. 080033) . Hubei Province: Cultivated in Wuhan Botanical Garden, Chinese Academy of Sciences , 15 m alt., 20 June 2022 (fl.), W. B. Xu 20230302 (HIB, barcode no. 0233004) .

C. luteopunctata : China. Sichuan Province: E. H. Wilson 5100 (IBSC); Emei Mountain, 10 July 1937, Chong-Shu Qian 6024 (PE); Leshan City , Mount Emei , 7 July 1941, Wen-Pei Fang 17200 (PE); Leshan City , Mount Emei , shishungou, 4 November 1952, Ji-Hua Xiong , Xiu-Shi Zhang & Xing-Lin Jiang 33464 (PE); Emei Mountain , near Hongchunping , 1000 m alt., 20 August 1957, Guang-Hui Yang 56774 (PE); Xuyong County, Shuiwei Town , Guandou Village , evergreen broad-leaved forest, 105°38'16"E, 28°16'39"N, 790 m alt., 8 June 2013, Xin-Fen Gao, Yun-Dong Gao & Wen-Bin Ju HGX11767 (CDBI); ibid., growing by the stream, under the forest, 105°23'44"E, 28°09'20" N, 14 September 2013, Wen-Bin Ju & Heng-Ning Deng HGX13448 (CDBI) . Yunnan Province: Yongshan County, growing in a ravine, 1400 m alt., 13 July 1932, H. T. Tsai 51132 (LBG); Jinping County , Mengla, Tuomazhai, 900 m alt., 28 June 2009 , Yunnan expedition team YN-ET40 0 (PE).

C. giraldii : China. Hunan Province: Yuanling County, Jiaomuxi, found at the mountain top, 1000 m alt., 23 June 1988, Wuling team 533 (IBSC); Zhijiang County , muyexi, in ravine, 90 m alt., 3 October 1988, Wuling team 1773 (IBSC); Xinning County , Ziyun Mountain , 1150 m alt., 20 October 1962, Lin-Han Liu 15240 (IBSC); Changsha, Lushan, wetland, 400-500 m alt., 2 July 1929, Shu-Zhi Xin S.H. 23 (IBSC); Chengbu County , Dalao Mountain , occurring under dense forest at the mountaintop, 1500 m alt., 12 July 1959, Pei-Xiang Tan 63685 (IBSC); Sangzhi County , Shadiping, Luojiatai, valley dense forest with a slope of 20°, 1500 m alt., 22, June 1958, Lin-Han Liu 9056 (PE) . Hubei Province: Yingshan County, growing near Miaoergang , subtropical coniferous broad-leaved mixed forest, roadside, 116°02'31.47"E, 30°58'41.70"N, 991 m alt., 10 August 2018, Xin-Xin Zhu et al. ZXX18584 (KUN) . Jiangxi Province: Jiujiang County, mingshan, obtained under the broad-leaved forest in the valley, by the stream, 200 m alt., 3 June 1993, Ce-Ming Tan 93192 (PE) . Guangdong Province: Ruyuan County, Wuzhi Mountain, Shikeng , 750 m alt., 8 August 1983, Nian-He Xia & Nian Liu 148 (IBSC) .

C. longifolia ; China. Guangdong Province: Zhaoqing, Dinghu Mountain , near Qingyunshi , 22 July 1979, Hua-Gu Ye 45 (IBSC); Yangshan County, Wuyuan , Yunyong Mountain , in the shade of the valley slopes, 1000 m alt., 6 June 1956, Liang Deng 1313 (PE) . Hainan Province: Sanya, Ganshiling Reservoir , 17 October 1987, Ze-Xian Li 2611 (IBSC); Wanning County, xinglong, 14 May 1995, Fu-Wu Xing et al. 6717 (IBSC) . Yunnan Province: Xishuangbanna Prefecture, Jinghong City , Mengyang Town , Guanping , by the edge of the forest, 900 m alt., 10 August 1977, Guo-Da Tao 17611 (HITBC); Cangyuan County, Nanla, Mangka, growing in dense forests within valleys, 1050 m alt., 6 July 1974, Yan-Hui Li 12620 (HITBC) .

Molecular phylogeny

Similar topology of the Bayesian and ML trees, both displaying monophyly of the Callicarpa was observed (Fig. 3 ). Overall, three well-supported primary clades were identified with a posterior probability and bootstrap percentages = 1. Notably, C. yongshunensis clustered with C. luteopunctata and both morphological (Fig. 4 ) and molecular phylogeny evidence revealed that these two species are closely related. The resulting phylogenetic tree could separate C. yongshunensis from C. giraldii and C. longifolia , while C. giraldii clustered with C. hainanensis and C. brevipes ; in addition, C. longifolia clustered with C. nudiflora . The results further confirmed previous conclusions that the phylogenetic relationship does not always reflect morphological similarity ( Chang 1951). For example, C. brevipes (section Callicarpa Verticirima ), C. giraldii (section Callicarpa Eucallicarpa ) and C. hainanensis (section Callicarpa Verticirima ) constituted a subclade with over 0.90 support, while C. luteopunctata (section Callicarpa Eucallicarpa ) and C. stoloniformis (section Callicarpa Verticirima ) were tightly clustered with C. longipes (section Callicarpa Eucallicarpa ) in the phylogenetic tree.

Figures

Figure 1. Images of Callicarpa yongshunensis Wen B. Xu, Xiao D. Li & Yan Ling Liu A inflorescence in ventral view B inflorescence in lateral view C fruit branch in lateral view D infructescence in ventral view E individual in the fruiting period of wild populations F roots developed from the node area of fruit branches G glands on the abaxial surface of the leaf H leaf, adaxial surface I leaf, abaxial surface J typical species natural habitat. Photos by Wen-Bin XU and Shu-Hui WANG.

Figure 2. The microstructure of flowers and fruits of Callicarpa yongshunensis A flower B longitudinally dehiscing anther C calyx and attached glands D petals and attached glands E young fruit and attached glands F bifid stigma G petiole nodes without transverse scar. Photos by Shu-Hui WANG.

Figure 3. Phylogenetic relationships amongst Callicarpa yongshunensis and other selected species. The numbers near the nodes are Bayesian posterior probabilities and Maximum Likelihood bootstrap percentages, respectively.

Figure 4. Morphological comparison between C. luteopunctata (A-D) and C. yongshunensis (E-H) A, E life form showing erect shrub and procumbent shrub B, F fruit branch C, G fruit colour D, H leaf behaviour in winter showing deciduous and evergreen phenotypes (Date: 27 February 2024). Photos by Wen-Bin XU.