Taxonomic revision of Physalis species (Solanaceae) in Korea

Article information

Abstract

INTRODUCTION

Physalis L. (땅꽈리속), comprising approximately 90 species, is one of the relatively large genera of Solanaceae (Pretz and Deanna, 2020). The genus is native to the new world, and its species diversity is mainly concentrated in the United States, Mexico, and India (Pretz and Deanna, 2020; Martínez et al., 2023). Physalis species commonly have axillary inflorescences with solitary flowers, and the most notable hallmark of this genus is its calyx, which expands and envelopes the edible berry (Ganapathi et al., 1991; Pretz and Deanna, 2020). Physalis species have ambiguous morphological boundaries among and even within species, often leading to debates about their classification (Sullivan, 2004; Raju et al., 2007; Pretz and Deanna, 2020). However, their life forms and the morphological features of the leaves, flowers, fruits, and hairs have traditionally been the main characteristics used for identification (Sullivan, 2004; Martínez et al., 2023).

In Korea, Physalis species are considered alien plants that were introduced starting in the early 1900s; they are currently observed growing as weeds along paths and roadsides (Kim and Kil, 2017). Physalis plants in Korea were first recorded by Nakai (1911), and various Physalis species have since been reported under Korean names such as “-kkoa-ri” and “-ttangkkoa-ri” (Park 1949) (Table 1). According to the recent literature, the Physalis species distributed in the Republic of Korea include P. alkekengi L. [or var. franchetii (Mast.) Makino], P. angulata L., P. minima L., P. lagascae Roem. & Schult., and P. longifolia Nutt., with suggestions regarding the potential distribution of P. pubescens L. (Lee, 1996a, 1996b; Park, 1999; Lee, 2006; Kim et al., 2018). Among these, P. alkekengi and certain varieties of this species are currently classified under the genus Alkekengi Mill (꽈리속) based on morphological, molecular, and nomenclatural studies (Pretz and Deanna, 2020; Martínez et al., 2023; POWO, 2024). Alkekengi features an inflated calyx enclosing the fruit at fruiting, similar to Physalis. However, it is distinguished by the fruit turning orange or red upon ripening and the calyx lobes being reflexed during flowering, which do not adhere to the white corolla (Pretz and Deanna, 2020; Martínez et al., 2023).

Table 1.

Compilation of Physalis species and their Korean names as recorded in the literature from the past to the present in the Republic of Korea, and their re-identification results from the present study

Various Physalis species have been reported in the Republic of Korea, with Korean names (Table 1). However, it is necessary to re-examine the actual existence of the species domestically and to reassess their morphological characteristics. Physalis angulata, commonly known as “Ttang-kkoa-ri,” is generally described as having ovate leaves with slightly toothed leaves, a corolla with spots, and a fruit calyx with five to ten ridges (Lee, 1996b; Park, 1999, 2009; Kim et al., 2018). However, these characteristics are not limited to P. angulata and can also be observed in other Physalis species, making the explanation unclear. Additionally, when examining photographs or illustrations identified as P. angulata, the morphology of the leaves, flowers, and fruits often does not match the key characteristics of P. angulata, or they exhibit features that resemble other Physalis species. Therefore, it is necessary to identify the characteristics of similar Physalis species accurately, including P. angulata, and to re-identify the species known as P. angulata in the Republic of Korea through field surveys and specimen observations. Moreover, the descriptions and photographic materials of P. wrightii reported by Park (1999) exhibit characteristics similar to those of P. angulata, re-identification through observations of voucher specimens is also necessary. Meanwhile, most descriptions lack detailed information pertaining to the key distinguishing features used for identifying Physalis species, such as the leaves, flowers, fruits, and hairs. This deficiency in detailed descriptions appears to complicate the identification of Physalis species (Lee, 1996b; Park, 1999; Lee, 2006; Park, 2009; Kim et al., 2018). Furthermore, there have been cases where multiple Korean names were used for one species or the same Korean name was applied to several species, representing another factor possibly adding confusion to the proper identification of Physalis species (Park, 1949; Yim and Jeon, 1980; Kim et al., 2018) (Table 1).

The aim of the present study was to identify Physalis species distributed in the Republic of Korea and their morphological characteristics for identification through a literature review, field surveys, and examinations of specimens and illustrations. Based on the research findings, revised descriptions and a taxonomic key are provided.

MATERIALS AND METHODS

To identify Physalis species accurately, protologues as well as studies and illustrations related to the genus were examined (Rydberg, 1896; Waterfall, 1958, 1967; Yim and Jeon, 1980; Ganapathi et al., 1991; Lee, 1996a, 1996b; Park, 1999; Sullivan, 2004; Lee, 2006; Park, 2009; Kim et al., 2018; Martínez et al., 2023; Sullivan, 2024). Based on this review, voucher specimens deposited in herbaria (ASU, B, BRIT, CM, COLO, DES, FHI, FLAS, G, GMUF, KAG, KH, LE, LINN, LSU, MA, MISS, MO, MSU, MT, NCU, NGCPR, OBI, P, PRC, RB, SBBG, TAC, TAAM, USF, VT, WU) were observed, along with photographs, to discern the morphological species characteristics (Appendix 1). For species confirmation and to prepare descriptions and a taxonomic key for Korean Physalis species, we observed the external morphologies of specimens stored at the Herbarium of the Korea National Arboretum (KH) and collected through field surveys conducted between 2019 and 2023. Measurements of specimens were conducted using a digital Vernier caliper (500-196-30 Absolute Digimatic Vernier Caliper; Mitutoyo, Tokyo, Japan). All voucher specimens used for these observations and measurements are housed at KH.

RESULTS AND DISCUSSION

1. Physalis angulata L., Sp. Pl.: 183, 1753; Boberella angulata (L.) E. H. L. Krause, J. W. Sturm, Deutschl. Fl. Abbild., ed. 2. 10: 61, 1903.—TYPE: PERU. Lima, 1778-1816, H. Ruiz & J. Pavon 9/2 (lectotype: MA, 815265, designated by Pretz and Deanna, 2020, Photo!).

Physalis angulata var. pendula (Rydb.) Waterf., Rhodora 60: 163, 1958.—TYPE: without locality, F.L. Harvey 65 (lectotype: MICH, 1229501, designated by Waterfall, 1958, not seen).

Korean name: 노란꽃땅꽈리 (No-ran-kkot-ttang-kkwa-ri).

English name: Cutleaf groundcherry (GBIF.org, 2024).

Herbs annual, up to 70 cm tall; glabrescent or sparsely puberulent. Roots taproot, rhizome absent. Stems erect, dichotomously branched. Leaves alternate or obscurely germinate, petiolate; leaf blade ovate to lanceolate, apex acute or acuminate, base rounded to attenuate, margin irregularly dentate to serrate with deeply toothed, rarely entire, 2.6–11.2 cm long, 1.3–6.2 cm wide. Inflorescences cyme, axillary, solitary, peduncle 1.5–2.1 cm long. Flowers calyx campanulate, 5-lobed, lobe apex acute, 3–6 mm long, glabrous to sparsely puberulent, ciliate, inflated at fruiting; corolla campanulate, rotate with short tube, 5-angled limbs, diameter 6–10 mm, yellow, with five pale brown spots or absent; stamens 5, epipetalous, anthers blue or yellow-tinged, inflexible after dehiscence; pistil ovary superior, locules 2, style elongate, slender, stigma capitate, 2-lobed. Fruits berry in inflated and laxly enclosed calyx; fruiting peduncle 1.5–2.3 cm long; inflated calyx 2.1–3.3 cm long, 1.7–2.5 cm wide, 10-ridged usually with dark purple veins; berry spherical, 7–13 mm in diameter. Seeds reniform, ca. 2 mm in diameter, flattened, foveolate, yellow.

Flowering and fruiting: August–November.

Origin: Americas (POWO, 2024).

Distribution in South Korea: Seoul, Incheon, Gyeonggi-do (Ansan-si, Dongducheon-si, Gwangju-si, Pyeongtaek-si, Yeoncheon-si), Chungcheongbuk-do (Cheongju-si), Chungcheongnamdo (Geumsan-gun, Taean-gun, Yesan-gun), Jeollabuk-do (Gochang-gun, Jinan-gun), Jeollanam-do (Damyang-gun, Muan-gun, Naju-si, Yeongam-gun), Gyeongsangnam-do (Changwon-si, Sacheon-si), Jeju-do (Jeju-si, Seogwipo-si).

Habitat: Roadsides, open fields, cultivated land.

Taxonomic note: P. angulata is the most similar to P. lagascae among domestic Physalis species, as both typically lack spots on the corolla and have ten prominent ridges on the inflated calyx during fruiting (Figs. 1E, F). However, the two species can be distinguished based on differences in the distribution of plant hairs and the morphological characteristics of the leaves, flowers, and fruits. Unlike P. lagascae, P. angulata is almost glabrous on the plant and calyx surfaces (Figs. 1B, D), and the leaf margin is irregularly serrate or dentate with deeply toothed (Fig. 1C). The fruiting peduncle is longer, and the inflated and laxly enclosed calyx is larger, usually with dark purple veins (Fig. 1F).

Fig. 1.

Photographs of Physalis angulata (Jeju-si): A. Plant. B. Stem. C. Leaf. D, E. Flower (D. Calyx. E. Corolla). F, G. Fruit. (F. Calyx. G. Berry).

Here, we recommend using the Korean name “No-ran-kkott-tang-kkwa-ri” for P. angulata (Table 1). This recommendation is based on our findings that the Physalis species commonly referred to as “Ttang-kkwa-ri” in Korea is most likely not P. angulata, but rather P. pubescens.

Physalis angulata was first recorded in Korea by Park (1949) and has since been referred to as “Ttang-kkwa-ri” in various publications (Lee, 1996a, 1996b; Lee, 2006; Park, 2009; Kim et al., 2018). Most references describe P. angulata as having ovate leaves, hairy calyces, and fruits with five to ten ridges (Lee, 1996a, 1996b; Lee, 2006; Park, 2009; Kim et al., 2018). However, these characteristics are more closely aligned with P. pubescens. Additionally, while P. angulata was believed to be primarily distributed in the southern regions of the Republic of Korea, upon a re-identification of specimens, including those of P. angulata and species considered synonymous with it (P. fauriei H. Lév. & Vaniot, P. minima, and P. repens Nakai) (Lee, 1996a, 1996b; POWO, 2024), revealed that the species which has been primarily collected in Jeju-do and the southern regions is actually P. pubescens. In contrast, P. angulata specimens were mainly collected in metropolitan areas, and those from Jeju-do were all collected in the late 1990s.

Considering the findings from the research, the species commonly known as “Ttang-kkwa-ri” is speculated actually to be P. pubescens, mistakenly identified as P. angulata previously, leading to confusion regarding the morphological characteristics of the two species (Table 1). Additionally, due to these misidentifications, Park (1999) appears to have misidentified P. angulata collected from Suin Industrial Road as P. wrightii A. Gray [= P. acutifolia (Miers) Sandwith] (Table 1). Whereas P. angulata and P. acutifolia have similar forms, P. acutifolia is cultivated primarily in gardens and is characterized by longer pedicels, wider-spreading corolla limbs, and smaller, inflated calyces bulgingly enclosed. P. acutifolia has not been confirmed in any domestic distribution to date and is considered not to have been introduced in the Republic of Korea.

Physalis angulata is currently distributed in the western and southern regions of the Republic of Korea, and these plants are usually found along roadsides, in open areas, and in cultivated lands. This species is estimated to have been introduced to the Republic of Korea in the early 1900s, and according to the classification of alien plant types in the National Arboretum’s Invasive Alien Plants in South Korea (Jeong et al., 2017), P. angulata is classified as a naturalized alien plant.

Meanwhile, in the past, a taxon with features similar to those of P. angulata but with narrower leaves and longer peduncles of 1.5–4 cm has been recognized as P. angulata var. pendula (Rydb.) Waterf. (Waterfall, 1958). However, Sullivan (2004), based on an analysis of more than 1,000 specimens, considered P. angulata var. pendula to show intergradation with P. angulata, with no significant differences in their geographical or habitual features. Therefore, P. angulata var. pendula is currently not recognized as a variant of P. angulata (Sullivan, 2004; POWO, 2024).

Physalis angulata var. pendula was found in the Republic of Korea in 2022 in open areas and along roadsides in Gochang-gun, where it co-occurred with P. angulata. However, it has not been found in other regions to date, and morphologically, it shows no significant differences from P. angulata, other than having narrower leaves and longer peduncles (Figs. 2B, C, E, F). Further research is required to determine whether P. angulata var. pendula should be recognized as a variety. In the present study, in line with Sullivan (2004), it was not considered a variant.

Fig. 2.

Photographs of Physalis angulata (left) and P. angulata var. pendula (right): A–C. P. angulata (A. Plant. B. Leaf. C. Peduncle). D–F. P. angulata var. pendula (D. Plant. E. Leaf. F. Peduncle).

2. Physalis lagascae Roem. & Schult., Syst. Veg., ed. 15(bis). 4: 679, 1819.—TYPE: SPAIN. Madrid, s.d., s.coll. s.n. (lectotype: MA, 237731, designated by Kale and Shinde, 2023, Photo!).

Physalis fauriei H. Lév. & Vaniot, Monde Pl. 10: 37, 1908.—TYPE: KOREA. “Quelpaert, Hongno,” Oct 1906, U. Fauriei 774 only (syntype: LE, 01008508, Photo!); “Quelpaert, Hongno,” Oct 1906, U. Fauriei 774 only (syntype: RBGE, E 00284489, Photo!).

Physalis repens Nakai, Bot. Mag. (Tokyo) 29: 3, 1915, syn. nov.—TYPE: KOREA. “Quelpaert, in agris Hongno,” 25 Sep 1908, E. Taquet 1150 (isotype: LE, 01008503, Photo!; E 00284490, E 00284490 Photo!).

Korean name: 노랑꽃누운땅꽈리 (No-ran-kkot-nu-unttang-kkwa-ri).

English name: Pygmy groundcherry (GBIF.org, 2024).

Herbs annual, up to 30 cm tall, sparsely villous with long and curved hair. Roots taproot, rhizome absent. Stems erect, dichotomously branched. Leaves alternate or obscurely germinate, petiolate; leaf blade elliptic-ovate to lanceolate, apex acute to attenuate, base cuneate to rounded, oblique, margin irregularly dentate, entire, sinuate, 1.7–3.2 cm long, 1–2.3 cm wide. Inflorescences cyme, axillary, solitary, peduncle 1–4 mm long. Flowers calyx campanulate, 5-lobed, lobe apex attenuate, 2–3 mm long, almost glabrous, villous on the veins, ciliate, inflated at fruiting; corolla campanulate, rotate with short tube, 5-angled limbs, diameter 5–8 mm, yellow with five pale brown or absent, rarely five purple spots; stamens 5, epipetalous, anthers yellow, rarely tinged, inflexible after dehiscence; pistil ovary superior, locules 2, style elongate, slender, stigma capitate, 2-lobed. Fruits berry in inflated and bulgingly enclosed calyx; fruiting peduncle 2–8 mm long; inflated calyx 1–2 cm long, 1–1.5 cm wide, 10-ridged with green or pale purple veins; berry spherical, 5–9 mm diameter. Seeds reniform, ca. 2 mm in diameter, flattened, foveolate, yellow.

Flowering and fruiting: August–November.

Origin: Central and South Americas (POWO, 2024).

Distribution in South Korea: Gangwon-do (Yeongwolgun), Chungcheongbuk-do (Danyang-gun, Okcheon-si), Jeju-do (Seogwipo-si).

Habitat: Cultivated land.

Taxonomic note: The species was initially described as Physalis parviflora Lag (1816). However, it was later found to be a homonym of P. parviflora Zuccagni (1806) (Kale and Shinde, 2023). Consequently, Roemer and Schultes published a replacement name, P. lagascae Roem. & Schult. (1819) (Kale and Shinde, 2023).

Physalis lagascae resembles P. angulata but differs in that it has long curved hairs on the stem and veins of the calyx (Figs. 3B, D) and occasional dark spots on the corolla, shorter fruiting peduncles, and an inflated calyx that is bulgingly enclosed with green or pale purple veins (Fig. 3F). In the Republic of Korea, P. lagascae can also be confused with P. pubescens owing to its small stature and hairiness (Figs. 3A, B, D). However, this species can be distinguished based on the previously mentioned characteristics of the hairs, peduncle, and calyx. Additionally, it can be differentiated easily based on the ten prominent ridges on the inflated calyx (Fig. 3F).

Fig. 3.

Photographs of Physalis lagascae (Okcheon-gun): A. Plant. B. Stem. C. Leaf. D, E. Flower (D. Calyx. E. Corolla). F, G. Fruit. (F. Calyx. G. Berry).

In this study, some type specimens of P. fauriei (Hippolyte and Vaniot, 1908) and P. repens (Nakai, 1915) are considered synonyms of P. lagascae (Table 1). The protologue of P. fauriei describes the plant as being found on Jejudo, with hairless leaves, small flowers, and short hairs distributed along the main veins and abaxial surface of the calyx (Hippolyte and Vaniot, 1908). This description only partially matches some of the characteristics of P. lagascae, such as small flowers and hairs on the calyx veins. The type specimens include those with record numbers 773 and 774, of which only the specimens of record number 774 exhibited short peduncles, small flowers, and long hairs along the main veins of the calyx, allowing it to be identified as P. lagascae.

In the protologue of P. repens, the species is described as having a glabrous stem, short peduncle, calyx with hairs along the veins, small corolla, and small fruits with five ridges (Nakai, 1915). An examination of the type specimen of P. repens revealed that while the base of the stem lacked hairs, sparse hairs were present on the upper stem and branches. The fruits were small, but the number of ridges could not be determined due to the specimen being pressed. Nonetheless, the plant was identified as P. lagascae due to the presence of long white hairs along the veins of the calyx, an indistinctly spotted corolla, and a short peduncle.

Physalis lagascae is a recently reported species (Kim et al., 2018); however, through specimen re-identification, it is presumed to have already been distributed in Korea in the early 1900s (Table 1). This species was historically found only on Jejudo, but recent field surveys have shown that it is now distributed in a few inland areas (Kim et al., 2018). Physalis lagascae is primarily found in cultivated lands and appears to have been unintentionally introduced during farming activities, temporarily growing and disappearing. This species is not widely distributed domestically or frequently observed in the field. As such, it is considered not fully naturalized in the Republic of Korea and a casual alien plant (Jeong et al., 2017).

3. Physalis longifolia Nutt., Trans. Am. Philos. Soc., n.s., 5: 193, 1837; Physalis lanceolata var. longifolia (Nutt.) Trel., Rep. (Annual) Arkansas Geol. Surv. 4: 207, 1891.—TYPE: USA. Arkansas, 1825, T. Nuttall s.n. (lectotype: G, G00200412, designated by Pretz and Deanna, 2020, Photo!); USA. Colorado, 20 Jul 2010, K. Mauz 2010–23 (epitype: COLO, 00978577, designated by Pretz and Deanna, 2020, Photo!).

Korean name: 긴잎땅꽈리(Gin-ip-ttang-kkwa-ri).

English name: Common groundcherry (GBIF.org, 2024).

Herbs perennial, up to 50 cm tall, glabrescent or sparsely puberulent. Roots rhizomatous. Stems erect, dichotomously branched. Leaves alternate or obscurely germinate, petiolate; leaf blade ovate to lanceolate or broadly lanceolate, apex acute, base cuneate to rounded, oblique, margin irregularly dentate, crenate, entire, 6.3–7.8 cm long, 2.1–3.6 cm wide. Inflorescences cyme, axillary, solitary, peduncle 1–1.3 cm long. Flowers calyx campanulate, 5-lobed, lobe apex attenuate, 1.1–1.4 cm long, pubescence almost on the base and veins, ciliate, inflated at fruiting; corolla campanulate, rotate with short tube, 5-angled limbs, diameter 1.5–2.5 cm, yellow with five dark brown to purple spots; stamens 5, epipetalous, anthers yellow or blue-tinged, inflexible after dehiscence; pistil ovary superior, locules 2, style elongate, slender, stigma capitate, 2-lobed. Fruits berry in inflated and laxly enclosed calyx; fruiting peduncle 1.5–1.8 cm long; inflated calyx 2.2–2.6 cm long, 1.7–2.2 cm wide, 10-ridged with green or purple veins; berry spherical, 5–8 mm diameter. Seeds reniform, ca. 2 mm in diameter, flattened, foveolate, brown.

Flowering and fruiting: August–November.

Origin: North America (POWO, 2024).

Distribution in South Korea: Gyeonggi-do (Yongin-si), Gangwon-do (Yeongwol-gun).

Habitat: Roadsides.

Taxonomic note: Physalis longifolia resembles P. angulata based on its hairless stem (Fig. 4B), toothed leaves (Fig. 4C), and the development of a 10-ridged calyx at fruiting (Fig. 4F). However, the two species differ in terms of their life forms, roots, and flowers. Physalis longifolia is the only perennial Physalis species found in the Republic of Korea and can reproduce via rhizomes (Fig. 4G). The calyx is covered with hair at the base, margin, and veins (Fig. 4D), whereas the corolla diameter is wider and has five dark spots (Fig. 4E).

Fig. 4.

Photographs of Physalis longifolia (Yeongwol-gun): A. Plant. B. Stem. C. Leaf. D, E. Flower (D. Calyx. E. Corolla). F. Fruit (calyx). G. Rhizomes.

Physalis longifolia is estimated to have been introduced to the Republic of Korea in the early 2000s and was first reported under the Korean name “Gin-ip-ttang-kkwa-ri” by Lee (2006) (Table 1). This name seems to refer to its leaf characteristics, and the species epithet “longifolia” means long leaves. At the time of its discovery, P. longifolia was distributed in Yongin-si (Lee, 2006), but its subsequent presence appears to be unclear. However, during a field survey in 2022, another habitat of this species was discovered in Yeongwol-gun. Considering the environment in which it was found, the species was inadvertently introduced during road construction activities, with approximately 30 individuals observed growing. Physalis longifolia is not only sparsely distributed domestically but also appears to be in the process of adapting to the environment in its natural habitats in the Republic of Korea. Accordingly, it is considered a casual alien plant (Jeong et al., 2017).

4. Physalis philadelphica Lam., Encycl. 2: 101, 1786.—TYPE: s.d. (lectotype: P, 00357705, designated by Waterfall, 1967, Photo!).

Physalis angulata var. philadelphica (Lam.) A. Gray, Manual, ed. 2: 340, 1856.

Korean name: 둥근땅꽈리(Dung-geun-ttang-kkwa-ri; 신칭).

English name: Husk tomato (GBIF.org, 2024).

Herbs annual, up to 50 cm tall, glabrescent or sparsely puberulent. Roots taproot, rhizome absent. Stems erect, dichotomously branched. Leaves alternate or obscurely germinate, petiolate; leaf blade ovate to lanceolate, apex acute, base cuneate to rounded, oblique, margin irregularly dentate, entire, 1.7–7.2 cm long, 1.1–2.7 cm wide. Inflorescences cyme, axillary, solitary, peduncle 4–6 mm long. Flowers calyx campanulate, 5-lobed, lobe apex acute, 4–9 mm long, almost glabrous, villous on the veins, ciliate, inflated at fruiting; corolla campanulate, rotate with short tube, 5-angled limbs, diameter 1.5–2.7 cm, yellow with five purple spots; stamens 5, epipetalous, anthers blue or yellow-tinged, convolute after dehiscence; pistil, ovary superior, locules 2, style elongate, slender, stigma clavate, 2-lobed. Fruits berry in inflated and bulgingly enclosed calyx forming a nearly globular shape; fruiting peduncle 4–8 mm long; inflated calyx 2–3.5 cm long, 1.5–2.4 cm wide, 10-ridged with green or purple veins; berry spherical, 1–2 cm diameter. Seeds reniform, ca. 2 mm in diameter, flattened, foveolate, yellow.

Flowering and fruiting: August–November.

Origin: North and Central Americas (POWO, 2024).

Distribution in South Korea: Gyeonggi-do (Namyangju-si), Gangwon-do (Yeongwol-gun), Gyeongsangnam-do (Geoje-si).

Habitat: Roadsides.

Taxonomic note: Physalis philadelphica resembles P. angulata and P. longiflora by its glabrous stem (Fig. 5B), its toothed leaf margins (Fig. 5C), and its inflated calyx has ten ridges (Fig. 5F). However, P. philadelphica can be distinguished easily based on its floral and fruit characteristics. This species features a short peduncle, flowers with a broad corolla, stamens with anthers that are convolute at dehiscence, and a pistil with a clavate stigma (Fig. 5E). The inflated calyx is bulgingly enclosed and nearly globularshaped (Fig. 5F). Considering the round shape of the fruit (Fig. 5F), we propose the Korean name “Dung-geun-ttangkkwa-ri” for this species.

Fig. 5.

Photographs of Physalis philadelphica (Yeongwol-gun): A. Plant. B. Stem. C. Leaf. D, E. Flower (D. Calyx. E. Corolla). F, G. Fruit. (F. Calyx. G. Berry).

Physalis philadelphica, known as tomatillo or Mexican tomato, is commonly used as an ingredient in foods such as salsa in its native region (Sullivan, 2004; Martínez et al., 2023; GBIF.org, 2024). This species is also cultivated and marketed as a crop in the Republic of Korea.

This species is considered a cultivated plant rather than an alien plant, unlike other Physalis species. However, some individuals are occasionally observed growing in disturbed areas. Observation of specimens deposited in the KH confirmed that this species has been collected from roadsides and paths in Namyangju-si and Geoje-si since the late 1990s. In 2023, two plants were found growing on a roadside in Yeongwol-gun. The plants found in Yeongwol-gun were not intentionally cultivated and had not escaped from cultivation sites. Instead, they seem to have inadvertently germinated from seeds introduced into the area via transportation equipment and construction materials during slope conservation work. The species appears to have an unstable establishment in the wild in the Republic of Korea, with disappearance and reappearance phenomena owing to the unintentional introduction of seeds.

5. Physalis pubescens L., Sp. Pl. 1: 183, 1753; Boberella pubescens (L.) E. H. L. Krause, J. W. Sturm, Deutschl. Fl. Abbild., ed. 2. 10: 61, 1903.—TYPE: LINN 247.11 (lectotype: designated by Waterfall, 1958, Photo!).

Physalis fauriei H. Lév. & Vaniot, Monde Pl. 10: 37, 1908, syn. nov.—TYPE: KOREA. Quelpaert, Hongno, Oct 1906, U. Fauriei 773 only (syntype: LE, 01008505, Photo!); Quelpaert, Hongno, Oct 1906, U. Fauriei 773 only (syntype: E, 00284488, Photo!).

Korean name: 땅꽈리 (Ttang-kkwa-ri).

English name: Downy groundcherry (GBIF.org, 2024).

Herbs annual, up to 30 cm tall, pubescent or villous with short and appressed or erect hairs, rarely glabrescent. Roots taproot, rhizome absent. Stems erect, dichotomously branched. Leaves alternate or obscurely germinate, petiolate; leaf blade ovate to deltoid, apex acute to attenuate, base cuneate to subcordate or oblique, margin irregularly dentate to entire, sinuate, 3.6–7.3 cm long, 2–4.6 cm wide. Inflorescences cyme, axillary, solitary, peduncle 4–9 mm long. Flowers bisexual, actinomorphic, calyx campanulate, 5-lobed, lobe apex attenuate, 3–4 mm long, pubescent, ciliate, inflated at fruiting; corolla campanulate with short tube, 5-angled limbs, diameter 6–11 mm, yellow with five dark purple spots; stamens 5, epipetalous, anther blue or yellow-tinged, inflexible after dehiscence; pistil ovary superior, locules 2, style elongate, slender, stigma capitate, 2-lobed. Fruits berry in inflated and laxly enclosed calyx; fruiting peduncle 1.1–1.8 cm long; inflated calyx 1–2 cm long, 7–15 mm wide, strongly 5-ridged with green or pale purple veins; mature berry spherical, 5–9 mm in diameter, yellow at maturity. Seeds reniform, ca. 2 mm in diameter, flattened, foveolate, brown.

Flowering and fruiting: August–November.

Origin: Americas (POWO, 2024).

Distribution in South Korea: Seoul, Incheon, Gyeonggi-do (Gwangju-si), Chungcheongnam-do (Buyeo-gun, Taean-gun), Jeollabuk-do (Buan-gun, Gimje-si, Jeongeup-si), Jeollanam-do (Goheung-gun, Haenam-gun, Jangheung-gun, Jindo-gun, Mokpo-si, Shinan-gun, Wando-gun, Yeongam-gun, Yeonggwang-gun, Yeosu-si), Jeju-do (Jeju-si, Seogwipo-si), Gyeongsangnam-do (Geoje-si, Namhae-gun, Tongyeong-si), Jeju-do (Jeju-si, Seogwipo-si).

Habitat: Cultivated land.

Taxonomic note: Physalis pubescens has morphological characteristics typical of the genus Physalis (Whitson, 2011; Pretz and Deanna, 2020). Plants are hairy with ovate to elliptical leaves with nearly entire margins (Figs. 6B, C). Its yellow corolla displays five distinct dark spots (Fig. 6E), and the fruiting calyx develops five ridges (Fig. 6F).

Fig. 6.

Photographs of Physalis pubescens (Jeju-si): A. Plant. B. Stem. C. Leaf. D, E. Flower (D. Calyx. E. Corolla). F, G. Fruit. (F. Calyx. G. Berry).

This species can potentially be confused with the domestic P. lagascae owing to its hairiness and compact size, including its stature, flowers, and fruits (Figs. 6A, C–F, Table 2). However, it can be distinguished based on its shorter hairs that are uniformly distributed on the calyx and by the corolla having five dark purple spots (Figs. 6D, E). Its fruiting peduncle is longer, and the inflated calyx develops five ridges (Fig. 6F).

Table 2.

Comparison of the morphological characteristics of five Physalis species in the Republic of Korea

The present study considers that some type specimens of P. fauriei (Hippolyte and Vaniot, 1908) are synonymous with P. pubescens (Table 1). According to the protologue of P. fauriei, only certain morphological descriptions, such as small flowers and short hairs densely covering the calyx, match the characteristics of P. pubescens. Among the type specimens, only the specimen of record number 773 was identified as P. pubescens due to its short hairs on the stems and calyx, small flowers, and nearly five ridges on the calyx. Based on these results, the type specimens observed at the time of the P. fauriei report included both P. lagascae and P. pubescens. Therefore, the protologue of P. fauriei describes the characteristics of both species together.

Physalis pubescens is a recently recognized species, but literature and specimen observations suggest that it was already introduced and distributed in the southern regions of Korea by the early 1900s (Lee, 1996a; Park, 1999, 2009; Kim et al., 2018). This species has often been misidentified as P. angulata and is referred to by various Korean names (땅꽈리, 좀땅꽈리, 애기 땅꽈리, 누운땅꽈리) (Park, 1949; Yim and Jeon, 1980; Lee, 1996a, 1996b; Park, 1999, 2009; Kim et al., 2018) (Table 1). It is now also observed in the western regions and appears to be the most commonly found naturalized alien plant among Physalis species in the Republic of Korea (Jeong et al., 2017).

CONCLUSION

This study aimed to identify the Physalis species distributed in the Republic of Korea and analyze their morphological characteristics through a literature review, specimen observations, and field surveys. As a result, five species were identified: P. angulata, P. lagascae, P. longifolia, P. philadelphica, and P. pubescens. These species were distinctly differentiated based on their life forms, roots, leaves, flowers, and fruit (Table 2) (Fig. 7).

Fig. 7.

Comparative photographs of the morphological characteristics of five Physalis species in the Republic of Korea: A–D. P. angulata (A. Leaf. B. Calyx. C. Corolla. D. Fruiting calyx). E–H. P. lagascae (E. Leaf. F. Calyx. G. Corolla. H. Fruiting calyx). I–L. P. longifolia (I. Leaf. J. Calyx. K. Corolla. L. Fruiting calyx). M–P. P. philadelphica (M. Leaf. N. Calyx. O. Corolla. P. Fruiting calyx). Q–T. P. pubescens (Q. Leaf. R. Calyx. S. Corolla. T. Fruiting calyx).

The species commonly known as “Ttang-kkwa-ri” and previously identified as P. angulata was actually found to be P. pubescens, while P. wrightii, which was reported as “No-ran-kkot-ttang-kkwa-ri” by Park (1999), was actually confirmed to be P. angulata. Additionally, based on an investigation of the type specimens of P. fauriei and P. repens, which were treated as the same species as P. angulata (Lee, 1996a, 1996b; POWO, 2024), some type specimens of P. fauriei and P. repens were considered synonyms of P. lagascae, while the remaining type specimens of P. fauriei were considered synonyms of P. pubescens.

The distribution of Physalis species in the Republic of Korea shows that P. angulata and P. pubescens are primarily found in the western and southern regions, with P. lagascae located in some areas of Seogwipo-si in Jeju-do and in Okcheongun and Danyang-gun in Chungcheongbuk-do, as well as in Yeongwol-gun in Gangwon-do. Physalis longifolia and P. philadelphica are currently found only in Yeongwol-gun, Gangwon-do (Fig. 8). Considering their introduction periods, domestic distribution, and degree of adaptation (Jeong et al., 2017), P. angulata and P. pubescens are classified as naturalized alien plants, P. lagascae and P. longifolia are considered as casual alien plants. Physalis philadelphica is a species known as a cultivated plant in the Republic of Korea, but it is occasionally found in the wild.

Fig. 8.

Distribution map of Physalis taxa in the Republic of Korea based on voucher specimens from the Herbarium of the Korea National Arboretum (KH).

The findings of the present study could facilitate the accurate identification of Korean Physalis species and can inform future taxonomic research on Physalis.

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