Impatiens sigmoidea Hook.f., Nouv. Arch. Mus. Paris. Nat.

Huang, Rong-Xin, Chen, Yi, He, Bai-Qiu, Li, Mei-Jun, Dong, Wen-Ke & Bai, Xin-Xiang, 2023, The rediscovery of Impatiens sigmoidea Hook. f. (Balsaminaceae) in Guizhou, China after more than 100 years, Phytotaxa 597 (1), pp. 1-7 : 2-4

Impatiens sigmoidea Hook.f., Nouv. Arch. Mus. Paris. Nat. sér. 4, 10: 267. 1908.

( Figs. 1 , 3 , 4 , 5A–C )

Type:— CHINA. Guizhou: Guiyang City, Kao-po [Gaopo Town], 11 September 1899, E. M. Bodinier & J. Laborde 2688 (lectotype here designated: E00313668; isolectotype: P00780758) ( Fig. 1 ). Remaining syntype: CHINA. Guizhou: Pin-fa [ Yunwu Town ], 21 August 1902, J. P. Cavalerie 287 (E00313667).

Notes:—According to the protologue of Impatiens sigmoidea ( Hooker 1908a) , three collections, viz. E. M. Bodinier 2688, J. Laborde & R. P. Bodinier 2689 and J. P. Cavalerie 287, were cited and no holotype was designated. Thus, these three collections are all syntypes. Two herbarium specimens E. M. Bodinier & J. Laborde 2688 are extant at E (E00313668) and P (P00780758). The specimen E00313668 agrees better with the information given in the literature and contains the pencil drawing of flower parts and the dissected flower parts pasted on the sheet. It also contains the mentioning of collecting locality (Kao-po). Therefore, the specimen E00313668 is designated here as the lectotype. However, E. M. Bodinier & J. Laborde 2689 is actually the type collection of I. labordei ( Hooker 1908a: 250) ( Figs. 1 & 2 ), and should not belong to I. sigmoidea .

Revised description:—Annual herb, 30–60 cm tall. Stem erect, simple, middle and upper part white or pink pilose. Leaves alternate, petioles 1.5–3 cm long, with 2 basal glands. Lamina 3–15× 1.5–5 cm, lanceolate or ovate-lanceolate, apex acuminate, margin serrulate, teeth mucronate, adaxial surface green, abaxial surface pale green, lateral veins 5–8 pairs, midvein white. Inflorescences in upper leaf axils, 1- or 2-flowered, peduncles 4–5 cm long, pedicels 8–15 mm long, bracteate above middle, persistent, ovate-lanceolate, apex acuminate, margin denticulate, 6–10 mm long. Flower white to greenish white, 2.5–3 cm deep. Lateral sepals 2, ovate, S-shaped curving, 6–9 mm long, 4–6 mm wide, apex acuminate, inequilateral, entire or denticulate on one side, abaxial midvein thickened. Lower sepal funnelform, mouth vertical, apex abruptly acuminate, base abruptly constricted into a middle inflexed, coarse spur, 1.5–2 cm long. Dorsal petal oblong, cucullate, apex mucronate, abaxial midvein thickened, carinate. Lateral united petals 2-lobed, 1.2–2 cm long, base with reddish dots, basal lobes ovate, small, 4–6 mm long, distal lobes dolabriform, 1.2–2 cm long, 8–15 mm wide, apex sharp and acuminate, abaxially with conspicuous auricle inflexed, apex obtuse. Filaments short, broad; anthers 2-locular, apically obtuse; ovary fusiform, erect, acuminate. Capsule clavate, 8–15 mm long, apically cuspidal; seeds few, 3–5 mm long, smooth.

Phenology:—Flowering and fruiting occur from May to October.

Distribution and habitat:— Impatiens sigmoidea is known in Huaxi District, Guiyang City, and Longli and Guiding counties of Qiannan Buyi and Miao Autonomous Prefecture. The species grows on gentle slopes next to streams or under broadleaved evergreen forests.

Additional specimens examined:— CHINA. Guizhou: Guiyang City, Huaxi District , Gaopo Town , 26°18′54.48″N, 106°47′58.8″E, elev. 1288m, 15 May 2018, X. X. Bai GP 2018051501 (GZAC); Qiannan Buyi and Miao Autonomous Prefecture , Longli County, Houzigou, 26°24′13.68″N, 106°59′42.91″E, elev. 1262m, 9 April 2022, X. X. Bai HZG 20220409 (GZAC) .

Proposed IUCN conservation status: —About 2100 mature individuals were known in the two subpopulations of Longli County and Huaxi District. And the ecological environment is well protected. According to the IUCN Red List Categories and Criteria ( IUCN 2019), it is assessed as Least Concern (LC).

Discussions on type localities:—The French missionaries E. M. Bodinier and L. Martin collected plant specimens in Guizhou between 1898 and 1901, such as Gaopo Mountain in Qingyan Town, Zhaosi (Tchao-se). The French Catholic priest J. P. Cavalerie collected plant specimens in Guiyang in 1894 and Yunwu Town (South of Guiding County, formerly known as [Pin-Fa]) from 1901 to 1909 ( Xiong & Cao 2017). Many plant specimens collected by the missionaries were shipped abroad and studied by many taxonomists in various countries.

After further literature review on place names, other plant specimens collected by E. M. Bodinier et al., and preliminary inference of their activity tracks during this period, it can be concluded that the type localities of I. sigmoidea shoule be Gaopo Town (=Kao-po), Huaxi District and Yunwu Town (=Pin-fa), Guiding County. One distribution of this species recorded in Flora of China as “Pingba” should be a misreport of Pin-fa. “Pingba” was formerly known as Anping (Gan-pin), and renamed as Pingba Country in1914, and now is the Pingba District of Anshun City.

Figures

FIGURE 1. A Lectotype of Impatiens sigmoidea (E. M. Bodinier & J. Laborde 2688, E00313668) B Isolectotype (P00780758).

FIGURE 2. A Syntype of Impatiens sigmoidea (J. P. Cavalerie 287, E00313667) B Isotype of I. labordei (E. M. Bodinier & J. Laborde 2689, E00313666) C Holotype of I. labordei (E. M. Bodinier & J. Laborde 2689, P00780709).

FIGURE 3. Impatiens sigmoidea. A–B Habit C Flower in face view D Flower in lateral view E Flowering branch F Base of stem and roots G Leaves H Inflorescences I–J Flower K Dissected flower L Bracts M Dorsal petals. Photographs by XIN-XIANG BAI.

FIGURE 4. Impatiens sigmoidea. A Flowering branch B Base of stem and roots C Flower in face view D Flower in lateral view E Dissected flower F Anthers with pedicel and bract. Drawn by YI CHEN.

FIGURE 5. Morphological comparison between Impatiens sigmoidea and I. lasiophyton. A–C I. sigmoidea. A–B Habit C Dissected flower. D–F I. lasiophyton. D Flower in face view E Flower in lateral F Dissected flower. Photographs by XIN-XIANG BAI.