Ipomoea L. is the most species-rich genus within the Convolvulaceae and is broadly distributed worldwide, especially in the tropical and subtropical (Austin and Huáman, 1996; Wilkin, 1999; Miller et al., 2004). It contains about 600–700 species are known (Austin and Huáman, 1996; Wilkin, 1999), or about 800–900 species in the broader generic concept based on recent phylogenetic analysis (Mabberley, 2008; Muñoz-Rodríguez et al., 2019; Eserman et al., 2020; Wood et al., 2020). Widely known as “morning glories” or “bindweeds”, the species of the genus present high economic importance, either as ornamental plants for diverse flowers (such as I. nil, I. purpura, I. quamoclit, and I. tricolor) or food crops, with the sweet potato (I. batatas) being one of the most widely cultivated species for its tubers (Wilkin, 1999; Muñoz-Rodríguez et al., 2018; Wood et al., 2020).

Ipomoea species tend to avoid closed forests but occur along streams, tracks, and roads and often favor rock outcrops where the forest cover is broken. These species are also frequent in secondary scrub and disturbed places around settlements. Ipomoea indica, I. nil, I. hederifolia, I. purpurea, and I. cairica are rarely found faraway from human habitation. Ipomoea alba, I. cairica, I. tricolor, I. indica, and I. quamoclit are sometimes clearly garden escapes (Wood et al., 2020).

Recently, Nine species of the genus Ipomoea have been reported in Korea: I. alba, I. batatas, I. hederacea, I. lacunosa, I. nil, I. purpurea, I. quamoclit, I. rubriflora (this is presumed to be an erroneous record of I. coccinea), and I. triloba (National Institute of Biological Resources, 2019). Among them, two species (I. batatas and I. quamoclit) are cultivation species and the other seven are alien species (Kim, 2018; Kang et al., 2020).

In November 2019, during a plant diversity field survey in Korean Peninsula, a new alien plant, Ipomoea cristulata Hallier f. was found in Namwon-si, Jeollabuk-do. Since then, we have investigated the growth status and changes in habitat. We here formally report the first occurrence of the I. cristulata in Korea (Figs. 1, 2). The Korean name is ‘Na-bi-ip-yu-hongcho’, based on a leaf shaped like a butterfly. We provide its photographs, morphological description, a taxonomic key to related taxa, and habitat details.

Ipomoea cristulata Hallier f., Meded. Rijks-Herb. 46: 20, 1922.—TYPE: MEXICO. E. Bourgeau 1061 (lectotype: G [barcode 00418183]; isolectotypes: K, P, S; designated by Wood et al., 2020: 577).

Quamoclit gracilis Hallier f., Bull. Herb. Boissier 7: 416, 1899; nom. illeg., non Ipomoea gracilis R. Brown (1810)

Korean name: Na-bi-ip-yu-hong-cho (나비잎유홍초).

Plants annual, stems twining, slender, glabrous or pilose at the nodes. Leaves petiolate; petioles 1–10 cm long; blades ovate, 3–5-lobed or less commonly entire, 2–9 × 1.5–7 cm, apex acute to acuminate, rarely obtuse, base cordate to subtruncate with rounded auricles, margins irregularly dentate, abaxially glabrous or pubescent. Inflorescences axillary, 3–7 pedunculate cymes; peduncles 3–13 cm long; bracts linearlanceolate, aristate, 1–3 mm long. Flowers bisexual; pedicels 4–12 mm long, becoming reflexed in fruit; bracteoles lanceolate, 1–2 mm long; sepals unequal, the outer sepals oblong, 3–3.5 × 2–2.5 mm, apex obtuse and rounded to truncate, muricate or smooth, with a subterminal arista 3–5 mm long, glabrous, the inner sepals oblong, 4–6 × 3–3.5 mm, apex truncate, with a subterminal arista 2.5–3.5 mm long; corolla hypocrateriform, 2–2.5 cm long, red or orange-red, glabrous; the limb 1–1.3 cm in diam.; stamens 1.8–2.2 cm long, exserted; anthers ca. 1.5 mm long; ovary ovoid, ca. 1 mm long, 4-locular, glabrous; styles ca. 2 cm long. Fruits capsules, globose, 7–8 mm long, the apiculum ca. 2 mm long. Seeds 4 per capsule, 4–5 mm long, ovoid, black to dark brown, finely tomentose.

Flowering: Sep. to early Nov.

Fruiting: Oct. to Nov.

Distribution and habitat: The native range of Ipomoea cristulata is dry, desert conditions regions of the Central U.S.A to Mexico (Wood et al., 2020). It is a climbing annual and grows primarily in the subtropical biome. In North America, Felger et al. (2012) recorded some 13 species from the Sonora desert region of Mexico-Arizona, listing I. cristulata, I. cardiophylla, I. costellata, and I. ternifolia as typical of this habitat. Brassica tournefortii, a recently introduced alien plant in Korea, inhabits dry desert ecosystems and is native to North Africa, the Caribbean, Central Asia, and neighboring countries in the West Indies. A study on the potential distribution of this plant by climate change scenarios evaluated that the possibility of rapid spread was very low because there were no large grasslands or desert areas in Korea. However, it is possible in the future to spread to islands and coastal regions, cultivated lands, disturbance zones with sand-rich soil, and dry lands at banks with environments similar to the current habitats (Kang et al., 2022). In the United States, I. cristulata is found primarily in the southwest in Arizona, New Mexico, and Texas but also in literature records for Kansas and Iowa in the central-north at higher latitudes. The climatic characteristics of Kansas and Iowa are similar to those of Namwon-si, where I. cristulata was found, with distinct seasonal changes and an average annual temperature of –10°C to 35°C. Macroscale climate factors and complex interactions in the ecosystem support recently introduced alien plants to form soil seed banks in a given region and spread to surrounding areas to be sustainable (Lim et al., 2020; Park and Choi, 2020). Three populations, ca. 100 m² in natural habitat area, are found in open habitats, dry and sunny roadsides, and cultivated lands on lowlands in Korea. Through four years of habitat monitoring, we confirmed the expansion of the habitat from 2019 to 2022. Ipomoea quamoclit was identified around the roadside at a distance of 200 m from the habitat of I. cristulata. Both species are estimated to have escaped from a nearby garden. It grows together with herbaceous plants such as Ipomoea coccinea L., Commelina communis L., Digitaria ciliaris (Retz.) Koeler, Humulus japonicus Siebold & Zucc., Erigeron annuus (L.) Pers., Coreopsis lanceolata L., Setaria viridis (L.) P. Beauv., Setaria faberi R. A. W. Herrm., Equisetum arvense L., Sedum sarmentosum Bunge, Bidens bipinnata L., Vigna angularis var. nipponensis (Ohwi) Ohwi & H.Ohashi, Conyza canadensis (L.) Cronquist, Miscanthus sinensis Andersson, Artemisia indica Willd., Bidens frondosa L., Eleusine indica (L.) Gaertn., Chelidonium majus var. asiaticum (H. Hara) Ohwi, Amaranthus lividus L., Chenopodium album L., Oenothera biennis L., Ipomoea hederacea Jacq.

Notes: Ipomoea cristulata was newly named from Quamoclit gracilis because another plant called Ipomoea gracilis already existed in the process of merging Calonyclion, Quamoclit, and Ipomoea into Ipomoea (Hallier, 1922). This species is similar to I. hederifolia and I. coccinea in its morphology. From I. hederifolia it is distinguished by the fruiting pedicel reflexed, the often muricate outer sepals, the inner sepals 4–6 mm long, and the narrower limb < 1.5 cm diam. From I. coccinea it is different by the leaves 3–5 lobe, hirsute adaxially, and corolla entire red or orange-red (Wood et al., 2020).

Specimens examined: KOREA. Jeollabuk-do: Namwon-si, Deokgwa-myeon, Gojeong-ri, 2 Nov 2019, Woong Lee, lw20191102001, lw20191102002, lw20191102003 (KNU); same locality, 16 Sep 2020, Woong Lee, lw20200916001, lw20200916002, lw20200916003 (KNU); same locality, 2 Oct 2020, Woong Lee, NIBR0000833005, NIBR0000833007 (KB); same locality, 29 Oct 2020, Woong Lee, lw20201029001, lw20201029002, lw20201029003 (KNU); same locality, 21 Sep 2022, Woong Lee, lw20220921001, lw20220921002, lw20220921003 (KNU), Woong Lee, NIBR0000833004, NIBR0000833006 (KB); same locality, 14 Nov 2022, Woong Lee, lw20221114001, lw20221114002, lw20221114003 (KNU).