Parnassia yunnanensis had been previously described based on mixed specimens containing materials partially belonging to P. cacuminum, which makes the application of P. yunnanensis ambiguous. Therefore, we lectotypified P. yunnanensis and meanwhile synonymized P. lanceolata var. oblongipetala under it. P. yunnanensis var. longistipitata was found more similar to P. cacuminum rather than P. yunnanensis, thus a new combination, P. cacuminum var. longistipitatacomb. nov. was proposed. Furthermore, other three names (P. vevusta, P. degeensis and P. kangdingensis) were reduced to synonyms of P. cacuminum too.

Taxonomy, lectotypification, Parnassia , morphology

Parnassia L. is a genus containing approximately 70 species (Ku and Hultgård 2001) which are predominantly distributed in arctic and temperate zones of the northern hemisphere and are mostly diverse in China and the Himalayas (Simmons 2004).

Parnassia yunnanensis Franch. (1896: 266) was described from Heqing, Yunnan province in China in 1896 which based on two collections (Delavay 710 and Delavay s.n.). Four duplicates of Delavay 710 were successfully traced from P and K (herbaria acronyms following Thiers 2016). However, one of these duplicates deposited in P (barcode number P00709380, Figure 1a) is a mixed specimen: an individual indicated by a circle bears obovate petals (magnified as Figure 1b, d), while the rest possess lanceolate petals (Figure 1c, e, magnified from the individual indicated by a square). Obviously, they are different taxa, the individual with obovate petals should be P. cacuminum Hand.-Mazz. (1931: 433). Franchet used ‘oblonga’ to describe the shape of petals in the protologue of P. yunnanensis, that made this name ambiguous, some new names were published to be closely related to P. yunnanensis but were actually close to or conspecific with itself or P. cacuminum.

Figure 1. 

A mixed type specimen of Parnassia yunnanensis. The sheet of Delavay 710 with barcode P 00709380 (a), the individual indicated with a circle and magnified should be determined as P. cacuminum (b, d), an individual represents the rest, indicated with a square and magnified (c, e), P. cacuminum (f) and P. yunnanensis (g) in the wild.

Pan described P. longipetaloides J.T. Pan (1985: 222) based on Jinshajing Exped. 6105 in KUN collected from Eryuan, Yunnan in 1963 and this name was placed in synonymy of P. yunnanensis in Flora Yunnanica (Chuang 2006). According to T.T. Yu 7429A collected from Muli, Sichuan province in 1937, P. lanceolata T.C. Ku (1987: 34) was described by Ku and soon after, she proposed a new variety, P. lanceolata var. oblongipetala T.C. Ku (1991: 82) based on an isotype of P. longipetaloides, Jinshajing Exped. 6105 stored in PE. Wu et al. (2008) reduced P. lanceolata to a synonym of P. yunnanensis, but they did not mention var. oblongipetala.

Parnassia yunnanensis var. longistipitata Z.P. Jien (1963: 255) was proposed in 1963. This variety has white petals which are significantly different from P. yunnanensis but closer to P. cacuminum. Parnassia venusta Z.P. Jien (1963: 257), P. degeensisT.C. Ku (1987: 30) and P. kangdingensis T.C. Ku (1987: 35) are three taxa that are morphologically close to P. cacuminum, but the authors compared them to some other taxa in the protologues when published them. Further studies in collections and field expeditions have been carried out to synonymise them in this paper.

This paper is based on the critical review of the protologues and examination of specimens in herbaria BJFC, CDBI, K, KUN, P, PE, HNWP, SM, SZ and online on Jstor Global Plants (https://plants.jstor.org/ accessed on 12 December 2016). The measurements provided herein were mostly taken from dried herbarium specimens, and certain features such as colours were supplemented with the information from field observation. By applying Art 9.1 and 9.2 of the ICN (McNeill et al. 2012) strictly, the lectotype was selected. Specimens examined were listed alphabetically.

Since the syntypes of P. yunnanensis belong to more than one taxon, a lectotype needs to be designated for it. Wu et al. (2008) cited the type of P. yunnanensis in their taxonomic work as “China. Yunnan, Hokin, Delavay 710 (holotype K!); Sichuan, near Tatchienlu, Pratt 542 (syntype, BM!)”. As Franchet did not mention Pratt 542 in the protologue when he described this new name, Pratt 542 should not be regarded as a syntype of P. yunnanensis. In addition, they did not use the phrase “designated here” or the term “lectotype” in the statement. According to Art. 7.10 and 9.23 of the ICN, their typification of P. yunnanensis was not effective. Franchet worked at P (Stafleu and Cowan 1976), so we select a well-presented specimen with barcode P00709378 that contains most individuals as the lectotype.

Ku stated in the protologue of P. lanceolata var. oblongipetala that it differs from the typical variety in having oblong petals, obtuse at the apex, and P. lanceolata differs from P. longipetaloides in having 3-lobed staminodes while the latter have obscure 4–6 dentate ones. By taxonomic revision of this variety, we determined that the type specimen of this name was indistinguishable from that of P. yunnanensis in terms of taxonomically important morphological characters (shapes of petals and staminodes, Figures 1g, 2a–d) and their general distribution ranges (both type specimens were collected from Mt. Maer between Hoqing and Eryuan). Thus we treated this variety as a new synonym of P. yunnanensis.

Parnassia venusta was described based on T.T. Yu 22666 collected from Gongshan, Yunnan by Jien. As concluded from the protologue, he thought that this species differs from P. cacuminum in two characters: leaves reniform, petals lanceolate-obovate, slightly fimbriated at the base (Figure 2i) while P. cacuminum has cordata leaves, petals late obovate, erose or slightly fimbriated at the base (Figures 1f, 2e, f). The difference in the shape of the leaves was observed and we found it do not held good; reniform to cordate leaves always occur within a population even within a single individual. Parnassia cacuminum has obovate petals, but it is variant, 4–9 mm in length by 2–5 mm in width are observed in the sample specimens, and no dividing line can be found amongst lanceolate-obovate, obovate and late obovate. Hence, we treated P. venusta as a new synonym of P. cacuminum.

In 1987, Ku proposed two new species, P. degeensis and P. kangdingensis from Dege and Kangding respectively. P. degeensis was described based on Y.W. Tsui 4997, which has only one sheet containing one individual with two flowers. Ku described the staminodes of this name as undulate or 5–7 dentates at the apex and compared it with P. farreri W.E. Evans (1921: 174), which differed significantly in the shape of petals. We examined the holotype of P. degeensis (Figure 2k); the petals were obovate with distinct veins, staminodes 3 lobed at the apex and that agreed well with P. cacuminum. Ku stressed in the protologue of P. kangdingensis that this new taxon was closely related to P. lanceolata. However, from the description, it could be concluded that this name was quite different from P. lanceolata (obovata white petal vs. lanceolata green petal) but close to P. cacuminum by the numerical characters which Ku used to distinguish them, such as heights of individuals and length of petals. As we examined the type specimens and observed the populations in Kangding (Figure 2g, h), variations of height from 2–9 cm and length of petals from 3–6 mm were found within a population. Therefore, we propose to recognise P. degeensis and P. kangdingensis as synonyms of P. cacuminum.

Figure 2. 

Morphology of the petals and staminodes in Parnassia. P. lanceolata var. oblongipetala (a, bJinshajinag Exped. 6105, the holotype), P. yunnanensis (c, dT.T. Yu 7429), P. cacuminum (eT.T. Yu 12254fY.M. Shu et al. sz286), P. kangdingensis (g, hY.M. Shu et al. sw365), P. venusta (iY.M. Shu et al. sw365), P. cacuminum var. longistipitata (jY.M. Shu et al. sw459), P. degeensis (kY.W. Tsui 4997, the holotype). Scale bar = 1 mm.

Not far from the location where P. kangdingensis was described in Kangding, a new variety, P. yunnanensis var. longistipitata was proposed. This variety has cordate leaves, elliptic to obovate white petals and flat, linear staminodes with entire or obscure 3 dentate apexes (Figure 2j). All these characters made it different from P. yunnanensis but close to P. cacuminum. The only difference between it and P. cacuminum is the linear shaped staminodes. The field observation found that these linear shaped staminodes were easily distinguished from those of P. cacuminum and they were stable within populations. Thus, it was proposed to recognise this taxon as a variety of P. cacuminum.

We are indebted to the curator and staff members of BJFC, CDBI, K, KUN, P, PE, HNWP, SM, SZ and WU herbaria for either providing images of specimens on their website or allowing us to examine collections in their care for this study. Lijuan Liu is thanked for providing magnified photos of type specimens. This study was funded by the Science and Technology Basic Work (grant no. 2013FY112100) and the National Natural Science Foundation of China (grant no. 31110103911).