Impatiens wutaishanensis (Balsaminaceae), a new species from Southeast Yunnan, China Author Liao, Rong-Li School of Life Sciences, Yunnan University, Kunming 650091, Yunnan, China & Yunnan Key Laboratory for Integrative Conservation of Plant Species with Extremely Small Populations / Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, Yunnan, China & University of Chinese Academy of Sciences, Beijing 100049, China Author Cai, Lei https://orcid.org/0000-0002-9251-2745 School of Life Sciences, Yunnan University, Kunming 650091, Yunnan, China Author Yu, Zhi-Yong Management Bureau of Jinping Fenshuiling National Nature Reserve, Jingping 661500, Yunnan, China Author Wang, Yue-Hua School of Life Sciences, Yunnan University, Kunming 650091, Yunnan, China wangyh58212@126.com Author Sun, Wei-Bang Yunnan Key Laboratory for Integrative Conservation of Plant Species with Extremely Small Populations / Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, Yunnan, China wbsun@mail.kib.ac.cn text PhytoKeys 2021 2021-04-16 176 43 53 http://dx.doi.org/10.3897/phytokeys.176.58825 journal article http://dx.doi.org/10.3897/phytokeys.176.58825 1314-2003-176-43 BDBA991D66035F7E81F2FFD7FDA59DC2 Impatiens wutaishanensis R.L. Liao & Lei Cai sp. nov. Figs 1 , 2 Type . China , Yunnan Province , Jinping County , Maandi , alt. 1650 m a.s.l. , 22°46'19.97"N , 103°28'29.78"E , 10 September 2016 , Lei Cai & Z.Y. Yu CL16050 ( holotype :1498854, KUN!; isotypes:1498855, KUN!) . Diagnosis. This species is similar to Impatiens parvisepala S.X. Yu & Y.T. Hou (2011: 57) ( Hou et al. 2011 ) in its racemose inflorescences, its alternate and aggregated or subverticillate at stem apex arrangement leaf, and its yellow flowers, but it can be distinguished by its conspicuous 0.5-2.4 cm long petiole (vs. sub-sessile or sessile), its shorter 10-35 cm high plants (vs. 35-60 cm high), its 3.5-12 x 1.5-4 cm elliptic to lanceolate-oblong leaf blades with cuneate bases (vs. 12-20 x 3.5-6 cm obovate or obovate-lanceolate blade with attenuate bases), its slightly incurved or narrowing to incurved spur (vs. nearly straight spur), and its racemose inflorescences with up to 22 flowers (vs. 6-8 flowers per inflorescence). Figure 1. Impatiens wutaishanensis R.L. Liao & Lei Cai A habit B whole plant C inflorescence D capsule E flower in front view F flower in lateral view G different parts of the flower. Figure 2. Impatiens wutaishanensis R.L. Liao & Lei Cai (drawn by R.M. Zhang) A habit B root C inner lateral sepal D outer lateral sepal E dorsal petal F lateral united petals ( F1 : upper petal F2 : lower petal) G lower sepal H ovary and stamens I flower in front view J flower in lateral view K partial view of leaf margin. Description. Perennial herb, 10-35 cm tall, glabrous. Root-system shallow, with runners and adventitious roots. Stem fleshy, erect, simple, lower nodes swollen. Leaves simple, alternate, aggregated or subverticillate at stem apex; petiole 0.5-2.4 cm long, leaf blade 3.5-12 x 1.5-4 cm, elliptic, lanceolate, or lanceolate-oblong, base cuneate, margin roughly crenate, mucronulate, apex acuminate, adaxial surface dark green, abaxial surface pale green, lateral veins 4-8 pairs. Racemes in the upper leaf axils, 1-4, 4.2-28 cm long, erect, each with up to 22 flowers. Pedicels 0.6-2.5 cm long, bracteate at base. Bracts ca. 8 mm long, lanceolate to subulate, apex acute, base obtuse, margin entire. Flowers yellow. Lateral sepals 4, light green, the outer pair ca. 5-8 x 3-4 mm, ovate or obovate; the inner pair ca. 8-13 x 1-3 mm, sickle-shaped, obliquely lanceolate, apex acuminate or caudate. Lower sepal 1.5-2.2 x 1.2-2 cm excluding the spur, yellow to yellowish green with reddish patches, obliquely infundibuliform, base gradually constricted into a spur, spur 1.2-3 cm long, slightly incurved or narrowing to incurved, apex rostellate. Dorsal petal 1.3-2.3 x 0.7-1.6 cm, yellow with nearly transparent base, obovate to ovate, apex acuminate, with an inconspicuous dorsal crest, base truncate or cuneate. Lateral united petals ca. 1.6-3 cm long, yellow with nearly transparent base and reddish patches; the upper petals ca. 1.5-2.3 x 0.7-1 cm, oblong; the lower petal ca.1.2-1.8 x 0.6-0.8 cm, reniform. Stamens 5, filaments linear, ca. 3 mm long, anthers obtuse. Ovary fusiform, slightly curved. Placentation axile with four locules. Capsule (immature) clavate, 2-2.5 cm long. Pollen morphology. Pollen grains triangular-round with three equal sides in polar view, and the equatorial view is elliptic, long-elliptic, PxE=16.56+/- 1.78 (14.51-21.73) x 30.00 +/- 0.98 (28.35-32.11) μm . 3-colpate, linear, the entire surface is covered with reticulate ornamentation, granules in lumina (Fig. 3 ). Figure 3. Micromorphology of Impatiens wutaishanensis R.L. Liao & Lei Cai under cryo-SEM A-D pollen A polar view B equatorial view C partial view D total view E-F leaf surface E adaxial epidermis F abaxial epidermis. Scale bar: 2 μm ( A, B ); 1 μm ( C ); 20 μm ( D-F ). Leaf surface micromorphology. The anticlinal walls of the epidermal cells on the adaxial surfaces are straight, while those of the abaxial surface are sinuate. The stomata only appeared on the abaxial surface of the leaf, the shape was anomocytic and the outline of the guard cells was suborbiculate (Fig. 3 ). Phenology. This new species was observed flowering from August to November, and fruiting from September to December. Distribution. This species is currently known from only two small subpopulations less than 10 km away (Shidong and Biaoshuiyan) in Jinping County of Southeast Yunnan, China (Fig. 4 ). The distribution area is very close to the border between China and Vietnam. We assume that this species should be distributed in Vietnam due to its similar habitat and proximity to the type locality, which will be verified by future investigation. Figure 4. Distribution of Impatiens wutaishanensis R.L. Liao & Lei Cai and I. parvisepala S.X. Yu & Y.T. Hou. Ecology. This new species has a runner with adventitious root produced from the nodes and was collected growing in the understory of forest at an elevation of 1300-1650 m. In the subpopulation in Shidong, the plants found coexist with the cultivated Amomum tsaoko Crevost & Lemarie ( Zingiberaceae ). In the subpopulation in Biaoshuiyan, the plants were found beside the artificial trail in a scenic area. The main accompanying species were Begonia Linn. sp. ( Begoniaceae ), Didymocarpus purpureobracteatus W.W. Smith ( Gesneriaceae ), Epigeneium amplum (Lindl.) Summerh. ( Orchidaceae ), Hedychium villosum Wall. ( Zingiberaceae ), Polygala fallax Hemsl. ( Polygalaceae ) and Vaccinium Linn. sp. ( Ericaceae ). Conservation status. This species is currently known only from Jinping County, Yunnan, China with one type locality and a subpopulation. The Extent of Occurrence (EOO) is less than 100 km2 and the known Area of Occupancy (AOO) is less than 15 km2. The conservation status can be evaluated as Vulnerable (VU) D2 based on IUCN Red List Categories and Criteria ( IUCN 2019 ). About 350 and 200 individuals were known in the two subpopulations of Biaoshuiyan and Shidong, respectively, and both are exposed to human disturbance. Therefore, we assess this species as a Plant Species with Extremely Small Populations (PSESP) ( Yang et al. 2020 ). Etymology. The specific epithet ' Impatiens wutaishanensis ' refers to the type locality where the new species was found, located in the Wutaishan area of Jinping Fenshuiling National Nature Reserve, Jinping County, Southeast Yunnan, China. The Chinese name is given as "五台山凤仙花" . Additional specimens examined. Paratypes . China . Yunnan Province : Jinping County , Maandi Town , Shidong. 22°46'19.97"N , 103°28'29.78"E , 1650 m a.s.l. , 5 August 2015 , Lei Cai et al., CL155 (KUN!); The same locality, 2 August 2020 , R.L. Liao & X.Y. Li , LRL202008003 (KUN!) ; Yunnan Province : Jinping County , Maandi Town , Biaoshuiyan , 22°43'56.61"N , 103°30'36.58"E , 1311 m a.s.l. , 2 August 2020 , R.L. Liao & X.Y. Li , LRL202008001 (KUN!) Discussion. The new species is most similar to Impatiens parvisepala in its racemose inflorescence, its yellow flowers with four lateral sepals. However, I. wutaishanensis is usually a shorter plant and its petiolate leaf blades are smaller and elliptic, lanceolate, or lanceolate-oblong. Its nectar spur is slightly incurved or narrowing to an incurved spur, and each inflorescence may have up to 22 flowers (Figs 1 , 2 ). In contrast, the plants of I. parvisepala are taller, the sessile or subsessile leaf blades are larger and obovate or obovate-lanceolate, the spur is nearly straight and the number of flowers per inflorescence is 6-8 ( Hou et al. 2011 ; Son et al. 2015 ). The distribution of these two species is geographically isolated from each other: Impatiens wutaishanensis , is confined to Southeast Yunnan Province with two subpopulations, where the I. parvisepala is recorded in western Guangxi and northern Vietnam (Fig. 4 ). In order to illustrate the morphological circumscription of the new species, we compare the new species with four species with similar morphological characters in Table 1 : Impatiens apalophylla Hook. f. (1908:243), I. clavigera Hook. f. (1908:2863), I. parvisepala and I. tianlinensis S.X. Yu & L.J. Zhang (2015: 253) ( Zeng et al. 2015 ). Table 1. Comparison of morphological characters in Impatiens wutaishanensis (n=30 for the measurements), I. parvisepala (data from Hou et al. 2011 and Son et al. 2015 ), I. apalophylla (data from Hooker 1908a and Chen et al. 2007 ), I. clavigera (data from Hooker 1909b, Hou et al. 2011 and Tan et al. 2015 ,) and I. tianlinensis (data from Zeng et al. 2015 ).

Character	I. wutaishanensis	I. parvisepala	I. apalophylla	I. clavigera	I. tianlinensis
Plant height	10-35 (16.71 +/- 5.30) cm	35-60 cm	30-60 cm	50-60 cm	50-80 cm
Length of petiole	0.5-2.4 (1.02 +/- 0.44) cm	sub-sessile or sessile	2-4 cm	1-2 cm	(0.5-) 1-2 cm
Shape of leaf blade	elliptic, lanceolate, or lanceolate-oblong	obovate or obovate-lanceolate	oblong-ovate or oblong-oblanceolate	obovate or oblanceolate	obovate to oblanceolate
Size of leaf	3.5-12 (7.53 +/- 1.86) x 1.5-4 (2.90 +/- 0.79) cm	12-20 x 3.5-6 cm	10-22 x 4-8 cm	8-15 (-18) x 3.5-5 cm	10-15 (-18) x 5-8 cm
Length of peduncle	4-28 (13.00 +/- 6.71) cm	15-17 cm	7-15 cm	8-10 cm	10-15 cm,
No. of flowers in an inflorescence	up to 22 flowers	6-8 flowers	4-10 flowers	5-9 flowers	3-5 (-7) flowers
Shape and length of spur	slightly incurved or incurved, gradually constricted, 1.2-3 (2.06 +/- 0.45) cm long	nearly straight, gradually constricted, 2-2.5 cm long	incurved, abruptly elongated, 2-2.5 cm long	incurved, abruptly narrowed, 5-6 mm long	involuted, abruptly constricted, 1-1.5 cm long
Bracts	lanceolate to subulate, persistent	lanceolate or subulate, persistent	invisible	ovate, caducous	ovate, deciduous
Lower sepal	obliquely infundibuliform, with reddish patches, 1.2-2.8 (1.94 +/- 0.38) x 0.8-2.2 (1.38 +/- 0.37) cm	obliquely infundibuliform, with reddish patches, 1.8-2 x 2.5-3 cm	narrowly funnel-shaped, with reddish patches, 3 cm	narrowly funnel-shaped, absent patch, 2 x 3 cm	slightly narrowly funnel-shaped, with reddish patches, 2.5-3.5 cm
Dorsal petal	ovate, 1.3-2.3 (1.80 +/- 0.28) x 0.7-1.6 (1.15 +/- 0.26) cm	obovate, 1.8-2.2 x 1.5-2 cm	ellipticum, 1-4 cm	obovate, ca. 2 cm	ovate, 10-12 x 7-9 mm
Lateral united petals	1.6-3 cm long, with reddish patches	2.8-3 cm long, with reddish patches	2-3 cm long, with apparent reddish patches	2-6 cm long, absent patch	2-2.5 cm long, with reddish patches
Pollen grains	30.00 +/- 0.98 (28.35-32.11) x 16.56 +/- 1.78 (14.51-21.73) μm	28.84 (27.98-30.17) x 20.57 (19.70-21.63) μm	31.85 (30.96-32.73) x 5.57 (5.13-6.75) μm	Missing data	30.13 (29.62-30.47) x 12.95 (12.68-13.54) μm