Research Article |
Corresponding author: Xin-Xiang Bai ( 254715174@qq.com ) Academic editor: Laurence J. Dorr
© 2022 Liu-Yi Ren, Yi Chen, Tao-Hua Yuan, Rong-Xin Huang, Mei-Jun Li, Xin-Xiang Bai.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Ren L-Y, Chen Y, Yuan T-H, Huang R-X, Li M-J, Bai X-X (2022) Impatiens bijieensis (Balsaminaceae), a new species from karst plateau in Guizhou, China. PhytoKeys 192: 1-10. https://doi.org/10.3897/phytokeys.192.77517
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Impatiens bijieensis X.X. Bai & L.Y. Ren, sp. nov. from northwest Guizhou Province, China, is described and illustrated. This new species is distributed discontinuously in Jiulongshan, Dafang County and Dajiucaiping, Hezhang County, both of which are in the Wumeng Mountain area, a karst plateau landform. The new species is morphologically similar to I. pterosepala Hook.f., I. lasiophyton Hook.f. and I. leptocaulon Hook.f. in height and flower shape and it especially resembles I. lasiophyton in pilosity. However, it differs in its deep purplish-red flower, 2-lobed lower sepal apex and cylindrical capsule. A detailed description, colour photographs and a provisional IUCN Red List assessment are provided along with discussions of its geographical distribution, ecology and morphological relationships with other similar species.
Balsaminaceae, China, Impatiens, morphology, new species
The genus Impatiens
Impatiens are morphologically characterised by their petals always united in pairs into lateral, united petals; fruit a fleshy, explosive capsule; seeds often dispersed elastically from valves when ripe (
The material for this study was mainly collected from the survey of wild ornamental plant resources in Guizhou Province, China. The morphological description of the new species was based on careful examination of fresh material in the field and herbarium specimens. Comparisons with other species were made to virtual herbarium specimens (GZAC, HC, HIB, IBK, IBSC and PE), photographs and literature (
China. Guizhou: Hezhang County, Xingfa Town, Dajiucaiping, 2763 m alt., 29°59'53"N, 104°45'29"E, 20 Aug 2021, X.X. Bai & L.Y. Ren DJCP 20210820 (holotype: GZAC!; isotype: PE!).
Impatiens bijieensis X.X. Bai & L.Y. Ren, sp. nov. is similar to I. pterosepala, I. lasiophyton and I. leptocaulon in plant height, leaf blade shape and flower shape, especially resembling I. lasiophyton in its pilosity and obtuse anther apices, but distinguished by its deep purplish-red flower, linear-lanceolate bract, apex 2-lobed lower sepal and cylindrical capsule.
Perennial herb, 30–60 cm high, densely pilose. Root-system developed, with adventitious roots on lower stem nodes. Stem fleshy, erect, branched. Leaves simple, alternate, aggregated at stem apex; petiole 0.3–0.8 cm long; leaf blade elliptic, ovate or ovate-lanceolate, 3.5–5 cm × 1.3–1.8 cm, base cuneate, with a pair of conical glands, margin serrulate, apex acuminate, adaxial surface densely pilose, green; abaxial surface pilose along veins, pale green, lateral veins 6–8 pairs. Inflorescences axillary, 2- or 3-flowered. Peduncles 1.5–1.8 cm long, pedicels 0.4–0.8 cm long, slender, bracteate above middle; bract 1, persistent, linear-lanceolate, 0.3–0.5 cm long, abaxial mid-vein thickened, margin membranous, ciliate.
Flowers deep purplish-red, 2.3–2.5 cm long. Lateral sepals 2, ovate, ca. 0.5 cm × 0.2 cm, margin ciliate, mid-vein carinate, apex acuminate or caudate. Lower sepal navicular, ca. 0.5 cm deep (excluding spur), mouth vertical, ca. 0.8 cm wide, narrowed into an incurved, long spur, ca. 2 cm, apex 2-lobed. Dorsal petal reniform, ca. 0.8 cm × 1.5 cm, base truncate or suborbicular, apex concave, abaxial mid-vein carinate, apex acuminate. Lateral united petals sessile, ca. 1.7 cm long, deep purplish-red with whitish-pink base and reddish patches near auricle, 2-lobed; basal lobes ca. 0.4 cm × 0.2 cm, oblong to obovate-oblong; distal lobes ca. 1 cm × 0.6 cm, dolabriform. Stamens 5, filaments linear, anther apices obtuse; ovary 5-carpellate, narrowly fusiform, 0.4–0.5 cm, erect. Capsule fusiform, 1.3–1.8 cm long, apex acuminate, 5-valved, fleshy. Seed ellipsoid, surface with irregular protrusions.
The specific epithet ‘bijieensis’ refers to the type locality where the new species was found, located in Bijie City, northwest Guizhou Province, China. The Chinese name is given as “毕节凤仙花”.
Flowers and fruits from August to October.
Impatiens bijieensis has been observed in Bijie City, Guizhou Province with subpopulations in Hezhang County and Dafang County. We found at Dajiucaiping, Hezhang that the plants grow along the creek on the slopes of gentle hilltops or on the side slope of the ridge, while some were found below the cliffs where water was dripping from streams. At Jiulongshan, Dafang, the population was distributed in evergreen broad-leaved forest margins.
Impatiens bijieensis was collected at elevations of 1915–2800 m. Species of Rubus coreanus Miq. (Rosaceae), Elatostema involucratum Franch. et Sav. (Urticaceae) and Allium wallichii Kunth (Liliaceae) were found to grow in the vicinity of this species.
This species is currently known only from Bijie City, Guizhou Province, China with two subpopulations. 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 the IUCN Red List Categories and Criteria (
China. Guizhou: Bijie City: Dafang County, Jiulongshan, 27°19'37"N, 105°52'50"E, 1915 m alt., 8 Sep 2021, X.X. Bai et al., JLS 20210908 (GZAC!).
Impatiens bijieensis is similar to I. pterosepala in floral morphology; both have dolabriform distal lobes of lateral united petals and ovate lateral sepals. The former differs from the latter in being pilose (vs. glabrate), having 2–3-flowered (vs. 1-flowered) inflorescences, deep purplish-red (vs. pale purple or purple-red) flower colour, serrulate (vs. crenate) leaf blade margin, conical (vs. globose) glands at leaf bases, mid-veins of dorsal petals carinate (vs. thickened, entire or undulate), margin of lateral sepals ciliate (vs. sometimes denticulate at one side), abaxial mid-veins of lateral sepals carinate (vs. narrowly carinate), anther apices obtuse (vs. acute) and capsules cylindrical (vs. linear).
Impatiens bijieensis is similar to I. lasiophyton mostly in its pilosity and elliptic, ovate or ovate-lanceolate leaf blades, but it can be easily distinguished from the latter by its deep purplish-red (vs. yellow or white) flowers, thickened abaxial mid-vein and ciliate margin, membranous bract (vs. hirsute bract and inconspicuous mid-vein), navicular and apically 2-lobed lower sepal (vs. broadly funnelform and unlobed), apex concave, abaxial mid-vein carinate dorsal petal (vs. apex obtuse, abaxial mid-vein thickened, cristate apically), margin of lateral sepal ciliate (vs. lateral sepal hirsute), and cylindrical (vs. linear) capsules.
Impatiens bijieensis is also similar to I. leptocaulon in the length of its petiole, serrulate leaf blade margin and navicular lower sepal, but differs from its adaxial surface densely pilose and abaxial surface pilose along veins (vs. glabrous), ciliate margined lateral sepals and carinate mid-vein (vs. hyaline margined, denticulate on one side). In order to illustrate the morphological circumscription of this new species, we compare the new species with three species with similar morphological characters in Table
Comparison of morphological characters in Impatiens bijieensis, I. pterosepala (data from
Character | I. bijieensis | I. pterosepala | I. lasiophyton | I. leptocaulon |
---|---|---|---|---|
Length of petiole | 0.3–0.8 cm | 1.5–2.0 cm | 1–3 cm | 0.5–1.5 cm |
Leaf blade | with a pair of conical glands at base, base cuneate, margin serrulate, adaxial surface densely pilose, abaxial surface pilose along veins | with 2 globose basal glands, base cuneate, margin crenate, both surfaces glabrous | base acute, margin coarsely crenate or crenate-serrate, both surfaces hirsute | with few basal glands, base narrowly cuneate, margin serrulate, both surfaces glabrous |
Bract | bracteate above middle, linear-lanceolate | bract above middle; lanceolate | bracteate below flower; lanceolate | bracteate above middle; lanceolate |
Flower | deep purplish-red | pale purple or purple-red | yellow or white | purple-red |
Lateral sepal | 2, ovate, margin ciliate, mid-vein carinate, apex acuminate or caudate | 2, ovate, margin sometimes denticulate at one side, abaxial mid-vein narrowly carinate, apex acuminate | 2 (or 4), subovate, hirsute, apex cuspidate | 2, subovate, long cuspidate, inequilateral, hyaline margined, denticulate on one side |
Lower sepal | navicular, narrowed into an incurved, long spur, spur apex 2-lobed | narrowly funnelform, narrowed into an incurved, slender spur | broadly funnelform, gradually narrowed into an incurved spur | navicular, narrowed into an incurved, long spur |
Dorsal petal | reniform, base truncate or suborbicular, apex concave, abaxial mid-vein carinate | orbicular, base cordate, apex slightly emarginate, shortly rostellate, abaxial mid-vein thickened, entire or undulate | orbicular, base cordate, apex obtuse, abaxial mid-vein thickened, cristate apically | orbicular, base unknown, apex rostellate, abaxial mid-vein carinate |
Basal lobes | oblong to obovate-oblong | oblong | small or rudimentary | orbicular, small |
Distal lobes | dolabriform | broadly dolabriform, larger | broadly dolabriform or sublunar | obovate-oblong |
Anther apex | obtuse | acute | obtuse | obtuse |
Capsule | cylindrical | linear | linear | linear |
Elevation | 1915–2800 m | 1500–1700 m | 1700–2700 m | 1200–2000 m |
Impatiens bijieensis (A–C) A flower in face view B flower in lateral view C flower dissected (Photos by X.X. Bai, in Hezhang County, 20 August 2021). Impatiens lasiophyton (D–F) D flower in face view E flower in lateral view F flower dissected (Photos by X.X. Bai, in Duyun City, 8 July 2021). Impatiens leptocaulon (G–I) G flower in face view H flower in lateral view I flower dissected (Photos by X.X. Bai, in Guiyang City, 22 June 2019).
The morphological characters, including perennial habit, racemose inflorescence, 5-carpellate ovary, cylindrical capsule and ellipsoidal seeds, indicate that Impatiens bijieensis is a member of the I. subg. Impatiens. It is known that Impatiens mainly grow in places with high relative temperature and low elevations, yet this new species is found in a karst plateau area that is characterised by its cold climate and high altitude. These ecological characters distinguish it from morphologically-similar species. Additionally, because of the development of tourism, its habitat is currently threatened by human activities.
This research was supported by National Natural Science Foundation of China (31960328) and Survey of Wild Ornamental Plant Resources in Guizhou Province (701256192201).