Impatiens longiaristata: Comparison
View Latest Version
Please note this is a comparison between Version 2 by Vivi Li and Version 1 by Shuai Peng.

Impatiens longiaristata (Balsaminaceae), a new species from western Sichuan Province in China, is described and illustrated here based on morphological and molecular data. It is similar to I. longiloba and I. siculifer, but differs in its lower sepal with a long arista at the apex of the mouth, spur curved downward or circinate, and lower petal that is oblong-elliptic and two times longer than the upper petal. Molecular analysis confirmed its placement in sect. Racemosae. 

  • lectotype
  • new taxa
  • phylogeny
  • protologue
  • Sichuan
  • taxonomy

1. Introduction

Impatiens L. (Balsaminaceae) is one of the most species-rich genera of angiosperms with more than 1000 species [1,2][1][2]. It is mainly distributed in tropical and subtropical Africa, Madagascar, southern India and Sri Lanka, eastern Himalayas and Southeast Asia [3,4][3][4]. In contrast to the wide distribution of the genus, many Impatiens species are endemic to specific mountains or valleys. Most of the species are forest plants, usually growing in moist semi-shaded places, rarely in semi-arid places [2,5][2][5]. Flowers of Impatiens are zygomorphic and have a wide variety of morphology and colors [4,5][4][5]. The diversity of species has resulted in an extremely complex interspecific relationship in this genus. Since Hooker and Thomson [6] provided the first infrageneric classification for Impatiens based only on morphological data, several infrageneric classifications of the genus have been proposed in the last century [7,8,9][7][8][9]. However, all of these classifications were based on a few macromorphological characters only. Fortunately, phylogenetic studies using nucleotide sequences have made great contributions to our understanding of the evolutionary relationships of Impatiens in the last two decades [4,5,10,11,12,13][4][5][10][11][12][13]. Of these studies, the most notable is that in which Yu et al. [5] proposed a new classification based on phylogenetic and morphological evidence in 2016. They divided this genus into two subgenera: I. subgen. Impatiens and I. subgen. Clavicarpa S. X. Yu ex S. X. Yu & Wei Wang. I. subgen. Impatiens was further divided into seven sections, of which I. sect. Racemosae Hook. f. et Thomson was characterized by its inflorescences racemose, many-flowered; lateral sepals 2, rarely 4 with inner 2 reduced; capsule linear; and seed ovoid.
China is a hotspot for the distribution of Impatiens and has numerous balsam species, most of which are distributed in the southwest of the country. The Flora of China lists 227 species, of which 187 are endemic [14]. According to Du et al. [15], a total of 69 new taxa of Impatiens have been described in China between 2000 and 2019, and 13 new taxa [16,17,18,19,20,21,22,23,24,25,26,27,28][16][17][18][19][20][21][22][23][24][25][26][27][28] and three new records [28,29,30][28][29][30] have been published in the last two years, bringing the total species reported for China to nearly 290.

2. Results and Taxonomic Treatment

2.1. New Taxon

Impatiens longiaristata S. Peng, G. W. Hu & Q. F. Wang sp. nov. (Figure 1A–I, the LSID for the name is: 77219511-1).
Plants 10 01812 g001 550
Figure 1. Impatiens longiaristata S. Peng, G. W. Hu & Q. F. Wang. (A) Habit, (B) Leaf, (C) Petiole, (D) Flower buds, (E) Inflorescence, (F) Flower anatomy, (G) Front view of flowers, (H,I) Lateral views of flowers (photographed by Shuai Peng).
Diagnosis: Impatiens longiaristata is similar to I. longiloba and I. siculifer, but can be distinguished by its lower sepal with a long arista (1 cm) appearance from the bud stage, spur curved downward or circinate, and lower petal that is oblong-elliptic, tip rounded, and two times longer than the upper petal.
Type: CHINA. Sichuan province, Shimian County, under a broad-leaved forest, 28°58′13″ N, 102°13′49″ E, elevation 2680 m, 1st September 2019, Shuai Peng, Jia-Xin Yang & Jun-Jie Wang PS-0096 (holotype: HIB 0189503!; isotype: HIB 0189504!, 0189505!, 0189506!).

3. Discussion and Conclusions

Impatiens longiaristata is morphologically and phylogenetically allied to I. longiloba and I. siculifer. The information available about the distribution of the latter two species suggests that I. longiloba is endemic to the type locality in Thailand and that I. siculifer is distributed in southwest China [9,10][9][10] and Vietnam [46][31]. Morphologically, all three have a similar type of inflorescences (racemose), the color of flowers (yellow with red spots), and the shape of lower sepals (funnelform). However, I. longiaristata can be easily distinguished from these two allied species by its long arista of the lower sepal, the shape of the spurs, and the lateral united petals (Figure 1). The lower sepal has an arista ca. 1 cm long at the apex of the mouth in I. longiaristata, while it is shortly rostellate or aristate (no more than 5 mm) in I. siculifer and apiculate in I. longiloba. The spur is curved downward or circinate in I. longiaristata, while it is curved upward in I. siculifer and slightly curved at the tip in I. longiloba. The lateral united petals of I. longiaristata are ca. 3 cm long, the upper petal is triangular and semi-circular, and the lower petal is oblong-elliptic, tip rounded, ca. 1.8 cm long, and two times longer than the upper petal, whereas in I. siculifer the lateral united petals are ca. 1.8 cm long, the upper petal is subtriangular, and the lower petal is lorate with an acuminate tip, and in I. longiloba the lateral united petals are ca. 2.5 cm long and the lower petal is lorate, elongate, and four times longer than the upper petal. The lateral veins of leaves are 5–7 pairs in I. longiaristata, but they are 10–12 pairs in I. longiloba and 5–11 pairs in I. siculifer. The lateral sepals are two pairs in I. longiaristata and I. longiloba, but just a pair in I. siculifer. The detailed morphological comparisons between new species and allied species are shown in Table 1. The results of the BI and ML analyses showed that these three species were in a well-supported clade (PP = 0.99 and BP = 85), in which I. longiaristata and I. longiloba formed a highly supported clade (PP = 1.00 and BP = 100) with I. siculifer forming a sister clade. It was also noted that I. longiaristata was morphologically closer to I. longiloba than to I. siculifer (Table 1).
Table 1. Morphological comparisons of Impatiens longiaristata, I. longiloba, and I. siculifer.
Characters I. longiaristata I. longiloba I. siculifer
Lamina shape obovate, elliptic, or elliptic-lanceolate oblong-elliptic ovate-lanceolate or elliptic-lanceolate
Lamina size 8–13 × 3–6.5 cm 3–11 × 1.2–5 cm 5–13 × 2.5–5 cm
Lateral veins 5–7 pairs 10–12 pairs 5–11 pairs
Length of peduncle 6.2–8.3 cm 3–5 cm 5.5–7 cm
Number of flowers 3–5 2–4 5–8
Bracts caducous caducous persistent
Number of lateral sepals 4 (2 pairs) 4 (2 pairs) 2 (1 pair)
Arista of lower sepal aristate at apex of mouth, arista ca. 1 cm long in bud and mature flower shortly apiculate shortly rostellate or aristate at apex of mouth
Shape of spur curved downward or circinate slightly curved at tip curved upward
Length of lateral united petals ca. 3 cm long ca. 2.5 cm long ca. 1.8 cm long
Shape of lower petal oblong-elliptic, tip rounded, 2 times longer than the upper petal lorate, 4 times longer than the upper petal lorate, tip acuminate
Based on detailed morphological studies and phylogenetic analysis, Impatiens longiaristata is a new taxon in science. Detailed descriptions, color plates, phylogenetic analysis, and comparisons with species of similar taxa are provided. The lectotypes of I. aquatilis and I. clavicuspis are also designated.

References

  1. Fischer, E. Balsaminaceae. In The Families and Genera of Vascular Plants VI; Kubitzki, K., Ed.; Springer Verlag: Berlin, Germany, 2004; pp. 20–25.
  2. Grey-Wilson, C. Impatiens of Africa; CRC Press: Boca Raton, FL, USA, 1980; pp. 1–248.
  3. Song, Y.; Yuan, Y.M.; Kupfer, P. Chromosomal evolution in Balsaminaceae, with cytological observations on 45 species from Southeast Asia. Caryologia 2003, 56, 463–481.
  4. Yuan, Y.M.; Song, Y.; Geuten, K.; Rahelivololona, E.; Wohlhauser, S.; Fischer, E.; Smets, E.; Küpfer, P. Phylogeny and biogeography of Balsaminaceae inferred from ITS sequence data. Taxon 2004, 53, 391–403.
  5. Yu, S.X.; Janssens, S.B.; Zhu, X.Y.; Lidén, M.; Gao, T.G.; Wang, W. Phylogeny of Impatiens (Balsaminaceae): Integrating molecular and morphological evidence into a new classification. Cladistics 2016, 32, 179–197.
  6. Hook, J.D.; Thomsom, T. Balsaminaceae. Praecursoresad Floram Indicam. Bot. J. Linn. Soc. 1859, 4, 106–157.
  7. Warburg, O.; Reiche, K. Balsaminaceae. In Die natürlichen Pflanzenfamilien III Teil. 5. Abteilung; Engler, H.G.A., Prantl, K.A.E., Eds.; Wilhelm Engelmann: Leipzig, Germany, 1895; pp. 383–392.
  8. Hook, J.D. An epitome of British Indian Species of Impatines. Rec. Bot. Surv. India 1904, 4, 1–58.
  9. Perrier de la Bâthie, H. Les Impatiens de Madagascar. Arch. Bot. Mémoire 1934, 7, 1–124.
  10. Janssens, S.B.; Geuten, K.; Yuan, Y.M.; Song, Y.; Küpfer, P.; Smets, E. Phylogenetics of Impatiens and Hydrocera (Balsaminaceae) using chloroplast atpB-rbcL spacer sequences. Syst. Bot. 2006, 31, 171–180.
  11. Janssens, S.B.; Geuten, K.; Viaene, T.; Yuan, Y.M.; Song, Y.; Smets, E. Phylogenetic utility of the AP3/DEF K-domain and its molecular evolution in Impatiens (Balsaminaceae). Mol. Phylogenetics Evol. 2007, 43, 1055–7903.
  12. Shajitha, P.P.; Dhanesh, N.R.; Ebin, P.J.; Laly, J.; Aneesha, D.; Reshma, J.; Augustine, J.; Linu, M. A combined chloroplast atpB–rbcL and trnL-F phylogeny unveils the ancestry of balsams (Impatiens spp.) in the Western Ghats of India. 3 Biotech. 2016, 6, 258.
  13. Rahelivololona, E.M.; Fischer, E.; Janssens, S.B.; Razafimandimbison, S.G. Phylogeny, infrageneric classification and species delimitation in the Malagasy Impatiens (Balsaminaceae). PhytoKeys 2018, 110, 51–67.
  14. Chen, Y.L.; Akiyama, S.; Ohba, H. Balsaminaceae. In Flora of China; Wu, Z.Y., Raven, P.H., Hong, D.Y., Eds.; Science Press: Beijing, China; Missouri Botanical Garden Press: St. Louis, MO, USA, 2007; Volume 12, pp. 43–113.
  15. Du, C.; Liao, S.; Boufford, D.E.; Ma, J.S. Twenty years of Chinese vascular plant novelties, 2000 through 2019. Plant. Divers. 2020, 42, 393–398.
  16. Peng, Y.C.; Peng, S.; Yang, N.; Xu, Z.G.; Cong, Y.Y. Impatiens bomiensis (Balsaminaceae), a new species from Xizang, China. Nord. J. Bot. 2020, 38, e02761.
  17. Lu, Z.C.; Pan, B.; Huang, F.Z.; Liu, Y. Impatiens gongchengensis (Balsaminaceae), a new species from Guangxi, Southern China. Taiwania 2020, 65, 1–4.
  18. Zou, C.Y.; Liu, Y.; Li, J.; Yu, S.X. Impatiens plicatisepala (Balsaminaceae), a new species from Guangxi, China. Taiwania 2020, 65, 544–547.
  19. Wang, J.S.; Lu, Y.F.; Xu, Y.L.; Jin, S.H.; Jin, X.F. Impatiens wuyiensis (Balsaminaceae), a new species from Fujian of Southeast China, based on morphological and molecular evidences. Bot. Stud. 2020, 61, 29.
  20. Xue, T.T.; Xia, C.Y.; Lidén, M.; Xu, W.B.; Lu, Z.C.; Chen, H.L.; Li, S.W.; Yu, S.X. Ignored Biodiversity in Acid Soil Islands in Karst Areas, South China: Impatiens longlinensis (Balsaminaceae), a New Critically Endangered Species. Syst. Bot. 2020, 45, 891–899.
  21. Gan, Q.L.; Li, X.W. Impatiens dasyvexilla, a New Species of Impatiens (Balsaminaceae) from Hubei, China. Novon 2020, 28, 253–255.
  22. Gan, Q.L.; Li, X.W. Impatiens zhuxiensis (Balsaminaceae), a new species of from Hubei, China. Nord. J. Bot. 2020, 38, e02686.
  23. Gan, Q.L.; Ke, Z.W.; Li, X.W. Impatiens shenglanii (Balsaminaceae), a new species from central China and its phylogenetic position. Ann. Bot. Fenn. 2020, 57, 217–221.
  24. Peng, S.; Cong, Y.Y.; Tian, J.; Zhang, C.F.; Hu, G.W.; Wang, Q.F. Impatiens bullatisepala (Balsaminaceae), a new species from Guizhou, China. Phytotaxa 2021, 500, 217–224.
  25. Song, Y.X.; Peng, S.; Cong, Y.Y.; Zheng, Y.M. Impatiens rapiformis, a new species of Impatiens with root tuber from Yunnan, China. Nord. J. Bot. 2021, 39, e03151.
  26. Song, Y.X.; Cong, Y.Y.; Kuang, R.P.; Peng, Y.C.; Zheng, Y.M. Impatiens sterilis, a rare new species of Impatiens with reduced sterile inflorescences from Yunnan, China. Taiwania 2021, 66, 48–52.
  27. Liao, R.L.; Cai, L.; Yu, Z.Y.; Wang, Y.H.; Sun, W.B. Impatiens wutaishanensis (Balsaminaceae), a new species from Southeast Yunnan, China. PhytoKeys 2021, 176, 43–53.
  28. Zhang, C.F.; Peng, S.; Tian, J.; Hu, G.W.; Wang, Q.F. A new species and a newly recorded species of Impatiens (Balsaminaceae) from Yunnan, China. Plant. Sci. J. 2020, 38, 437–447.
  29. Peng, S.; Hu, G.W.; Cong, Y.Y.; Wang, Q.F. Impatiens dalaiensis, a newly recorded species of Impatiens from Yunnan, China. Plant. Sci. J. 2019, 37, 569–571.
  30. Zhang, Q.Y.; Peng, S.; Peng, Y.C.; Cai, X.Z.; Cong, Y.Y. Impatiens tripetala, a new record species of Impatiens from China. Plant. Sci. J. 2020, 38, 320–322.
  31. Pham, T.T.; Van, T.D.; Nguyen, T.T.; Phung, T.T. Impatiens siculifer (Balsaminaceae): A new record for the flora of Vietnam. Acta Phytotaxon. Geobot. 2019, 70, 63–66.
More
© Text is available under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/)
Video Production Service
Feedback