﻿Five new synonyms for Impatiensprocumbens (Balsaminaceae) in China

﻿Abstract In the revision on the genus Impatiens L. in China, we found that there were synonyms amongst some species. Impatiensprocumbens Franch. morphologically resembled I.reptans Hook.f., I.crassiloba Hook.f., I.ganpiuana Hook.f., I.atherosepala Hook.f. and I.rhombifolia Y.Q.Lu & Y.L.Chen. After a thorough morphological study, based on original literature, type specimens and field surveys, it was found that the above six species of Impatiens had no substantial differences in morphological characters and there was continuity in geographical distribution. Therefore, we determined that I.reptans, I.crassiloba, I.ganpiuana, I.atherosepala and I.rhombifolia are the synonyms of I.procumbens. At the same time, we present the color photographs, supplementary descriptions of morphology, and geographical distribution. The lectotype of I.procumbens and I.reptans are also designated here.


Introduction
In China, 352 species of Impatiens have been recorded, including 273 species endemic to China, which are concentrated throughout the Qinling Mountains, southern Tibet, the Hengduan Mountains, Yunnan-Guizhou-Guangxi karst region, the middle and lower reaches of the Yangtze River and other regions (Yuan et al. 2022). It is well known that Impatiens species are notoriously difficult to identify, because of their abundant character variations and morphological similarities, which makes the boundary between species very blurred (Grey-Wilson 1980;Cong 2007;Tian et al. 2007). From the perspective of research history, there were many factors in the early published species, such as the distance between collectors and researchers, the collection of specimens with the same number in different herbaria, the change of place names etc., all of which have led to taxonomic problems, for example, the same species with different names, the absence of characters, and incorrect records. Additionally, these classification problems have not been resolved so far, which is not conducive to the research of Impatiens, but also causes some obstacles in the research for identification of the genus Impatiens in China. I. procumbens was published by Franchet (1886) on the basis of specimens collected from Dali, Yunnan Province. I. reptans, I. crassiloba, I. ganpiuana, and I. atherosepala were described by J. D. Hooker, based on specimens collected from Guizhou Province by E. M. Bodinier and J. P. Cavalerie (Hooker 1908a, b). I. rhombifolia was published by Chen and Lu (1990), based on specimens collected from Mount Emei, Sichuan Province. Yu (2008) mentioned that I. reptans, I. ganpiuana, I. procumbens and I. rhombifolia were very similar in morphology and may be described repeatedly. Through extensive field investigations and textual research of specimens, it was found that there were no essential differences amongst the above six species. In addition, the guidelines and recommendations of Article 9 of the ICN (Turland et al. 2018) have been followed while designating the lectotype.

Materials and methods
For morphological comparisons, we reviewed the original literature and related records, including the original literature description of each species, information of type specimens, synonyms and geographical distribution. The main sources of original literature are from Tropicos (http://www.tropicos.org), IPNI (http://www.ipni. org) and other websites. Otherwise, we also critically checked type specimens or high-resolution images of specimens involved in this study in BM, E, K, P, NY, WU, PE, IBSC, IBK, KUN, HGAS, GZAC, GZTM, SWFC and conducted fieldwork of type localities in Sichuan, Guizhou and Yunnan Provinces. We have obtained more than 10 field collections. Herbarium specimens were chosen carefully. We dissected the flowers of the plant in the field or in the habitat itself after collection of the plants. And various morphological characters, such as leaf size and shape, inflorescence type, flower color, etc., were carefully observed, measured and quality photographs were taken.

Results and discussion
After consulting the type specimens ( Fig. 1) of Impatiens procumbens from Dali, Yunnan, I. reptans from Guiyang, Guizhou (Fig. 2) and I. rhombifolia from Emei, Sichuan (Fig. 4B), as well as the specimens in domestic and foreign herbaria and relevant  literature records, it was found that there were no obvious differences in morphology amongst them (Table 1).
In the process of textual research on the type specimen of Impatiens reptans (Figs 2, 5A) , we found that J. D. Hooker did not designate a holotype in keeping with the practice of the time, the specimen P00780766 ( Fig. 2A) 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. Therefore, it is designated here as the lectotype. We also found that the labelling information of the isolectotype (E00313595) was marked "An idem au no. 1782?". At the same time, the vernacular name "Impatiens ganpiuana Hf Vav" (Fig. 2B) was found on the label at the lower right corner. These two uncertainties point to the need for further textual research of I. ganpiuana. Meanwhile, the collection information marked on the type specimens of I. crassiloba (Fig. 4A) and I. ganpiuana (Fig. 4C) were the same, namely E. M. Bodinier 1782, the collection time of the latter being 9 August, 1897. Although there was no collection time on the specimen of the former, it could be inferred that the collection time may be from the same period according to the marked information that the specimens were received on 26 April 1898. Compared with the character description of the protologue, the differences mainly lay in the shape of the lower sepal and anther (Table 1), but by examining type specimens (Figs 4C, 5B), the shape of the lower sepal of I. ganpiuana should be cymbiform, so there was no obvious difference, except for the different anther. At the same time, we found that Impatiens atherosepala is relatively close to the above plants of genus Impatiens, the type locality actually being Pingfa, Guiding County, which the "Flora of China" (Chen et al. 2007) misquoted as Pingba. From the type specimen (Figs 4D, 5D), it can be seen that the typical features are leaves lanceolate, margin with spinescent-serrate, 1-flowered inflorescence and lateral sepals ovate, with long aristate. The population we found in Pingfa, Guiding County ( Fig. 6A-D) conformed to the description of these characters. Through extensive field investigations (Figs 6, 7), it was found that the leaf shape of genus Impatiens varied greatly and as a   taxonomic character, it was not reliable. Meanwhile, the lateral sepals of I. procumbens, I. reptans, I. crassiloba, I. ganpiuana, I. atherosepala and I. rhombifolia had a tendency to extend and grow.
In addition, it can be seen from the type localities and other distribution points that the geographical distribution of these species is continuous and there is no obvious geographical isolation (Fig. 3).
It can be seen that there is no obvious difference in the morphology of the above six species and the geographical distribution is widespread. Since Impatiens procumbens is the earliest name published, we concluded that I. reptans, I. crassiloba, I. ganpiuana, I. atherosepala and I. rhombifolia are the synonyms of I. procumbens. Franchet (1886) did not specify the type specimen when publishing the I. procumbens. Four specimens (collection no. 1949, collected by M. I'Abb é Delavy) made of flowering plants collected on 16 November 1885 are now in P (P04543629, P04543628, P04543627, P04543626), of which specimen P04543626 (Fig. 1A) is more consistent with the information described in the protologue, as well as containing complete plant organs and collection information. Therefore, P04543626 is designated as the lectotype here and P04543627, P04543628 and P04543629 are the isolectotypes.