Prunus × nudiflora explained

Prunus × nudiflora (king cherry, 왕벚 wangbeot, 왕벚나무 wangbeonnamu or 왕벚꽃 wangbeotkkot) is a Korean native cherry tree originating from Jeju Island. It is a distinct species from Japanese native Yoshino cherry. King cherry is a rare plant and listed as an endangered species.^{[1] [2]} As of April 2017, 194 king cherry trees were growing around Mt. Halla in Jeju Island.^[3] According to Gen-ichi Koidzumi, king cherry is erroneously believed to be discovered by a French missionary Émile Joseph Taquet although what he discovered was a different species.

There have been disputes over the origin of king cherry and Yoshino cherry. Both are suspected hybrids, with doubts about the parent species. In 2007, a study conducted on the comparison of king cherry and Yoshino cherry concluded that these trees were categorized as distinct species.^[4] However, South Korean media assert that king cherry is the same species as Yoshino cherry.^{[5] [6] [7] [8]} In Korea most of the places for cherry blossom festivals, including Yeouido and Jinhae, are still planted with Japanese Yoshino cherry trees.^{[9] [10] [11]}

Name

In 1901, Yoshino cherry was given a scientific name Prunus yedoensis by Jinzō Matsumura after its place of origin Yedo (current day Tokyo).^[12] In the early 1900s, king cherry was thought to be the same species as Yoshino cherry, it is called Prunus yedoensis, the same scientific name as Yoshino cherry. After Ernest Henry Wilson suggested Yoshino cherry is a hybrid between Prunus subhirtella var. ascendens (Edo higan) and Prunus lannesiana (Oshima zakura) in 1916,^[13] Yoshino cherry came to be called Prunus × yedoensis.^[14] However king cherry still remained to be called Prunus yedoensis which is originally given to Yoshino cherry. In 2016, Katsuki et al. proposed a new name Cerasus × nudiflora after king cherry was found to be a hybrid by Cho in 2014 and shown to be genetically distinct from Prunus × yedoensis.^[15]

The Korean name wangbeonnamu (왕벚나무, king cherry) was created in 1963 when the Korean official plant resource survey team found three trees, until then it was called sakuranamu (사쿠라나무, sakura) or teolbeonnamu (털벚나무, hairy cherry).^{[16] [17] [18]} Wangbeonnamu means "king cherry tree" while wangbeotkkot means "king cherry blossom". The Korean name wangbeonnamu or wangbeotkkot does not distinguish Yoshino cherry from king cherry because they have been thought to be the same species. If necessary, Yoshino cherry is referred to as someiyosino (소메이요시노), a transliteration of a Japanese name for Yoshino cherry.

Characteristics

King cherry is quite rare in number in its habitat. In 1908, a single tree was discovered in the north slope of Mt. Halla near Gwaneumsa Temple by Taquet although according to Koidzumi it was a different species. In 1932, Koidzumi discovered a single tree in the south slope of Mt.Halla. In 1962, the first Korean official plant resource survey team was established and found three trees. Next year in 1963, the team found another three trees.^[19] In 1965, Han Chang-yeol reported that wild cherry trees which grow in Mt. Halla in Jeju Island are mostly Prunus subhirtella var. pendula form. ascendens (Edo higan) and Prunus donarium (Yamazakura) and king cherry is rare in number, around 10 individuals, having been found in a half century.^{[20] [Note 2]} In 1998, Kim Chan-soo reported that 33 king cherry trees were found around Mt. Halla. From March 2015 to October 2016, Warm-Temperate and Subtropical Forest Research Center, Korea Forest Research Institute conducted a survey of king cherry on Mt. Halla. The center found 194 king cherry trees are growing in 173 locations. The trees are located at altitudes between 165 m and 853 m. The trees range 5–19 m in height, 15–145 cm in diameter and 15–265 year old.^[3]

King cherry is morphologically similar to Yoshino cherry. When Yo Takenaka went to the Jeju Island in 1933, he observed that the king cherry's hairs on calyx lobes and on the lower side of leaves were less numerous, and the peduncles were shorter. In 1998, Chan-soo Kim studied the morphological variation on 18 characters in flowers, leaves, fruits, and seeds. Most characters of king cherry were smaller in size than those of Yoshino cherry although the limits of variation of the characters were somewhat wide in king cherry. The most prominent difference is that the calyx tube of Yoshino cherry is cup-shaped, whereas it is wedge-shaped in king cherry, in addition, the inflorescences of Yoshino cherry are corymbose while those of king cherry are umbelliferous.^[21]

History

• In 1908, a French missionary Taquet discovered a native cherry in Jeju islands.
• In 1912, a German botanist Koehne gave it a scientific name of Prunus yedoensis var. nudiflora as it deserves to be a separate variety from Yoshino cherry according to the variations observed.^{[22] [Note 1]} Although this species called Eishu zakura is a variation of Yoshino cherry, from then it was misrepresented that Yoshino cherry was growing naturally in Jeju Island.
• In 1916, Ernest Henry Wilson examined a specimen of King Cherry. He wrote "As far as I could judge it is undoubtedly a state of P. yedoensis Matsumura, ... To me the evidence is inconclusive, and I do not think the last word on the origin or native country of P. yedoensis Matsumura has yet been heard."^[13]
• In 1932, Koidzumi discovered that Yoshino cherry (currently identified as king cherry) along with the cherry which was found by Taquet were growing naturally and reported that Yoshino cherry is originated on Jeju island. Also Koidzumi identified that Prunus yedoensis var. nudiflora which was found by Taquet and named by Koehne is an independent species from king cherry and named it Prunus nudiflora (Koehn) Koidz. nom. nov. (Eishu zakura)　which is a synonym of Prunus quelpaertensis Nakai (Tanna-yamazakura).^{[23] [24]} Korea National Arboretum lists this species as Jejubeojnam (제주벚나무, Jeju cherry), a distinct species from king cherry in its Korea Biodiversity Information System.^[25]
• In 1933, Takenaka visited Jeju island and observed the tree which Koidzumi found. The tree was growing wild, showed differences from P. yedoensis; the hairs on calyx lobes and on the lower side of leaves were less numerous, and the peduncles were shorter. He concluded that it could not be P. yedoensis.
• In 1962, Takenaka ruled out the possibility of Korean origin of Yoshino Cherry by the morphological study.^{[26] [27]}
• In 2005, Yong-hwan Jung et al. conducted the phylogenetic analysis using sequences from both rbcL gene and trnL-trnF intergenic spacer of chloroplast DNA and concluded that king cherry and Yoshino cherry are clearly genetically distinguished from each other.^{[28] [29] [30]}
• In 2007, Mark S. Roh et al. analyzed king cherry and Yoshino cherry with inter-simple sequence repeat (ISSR) markers and sequence analysis of two chloroplast DNA　genes, rpl16 and trnL-trnF spacer and showed that king cherry can be considered indigenous and sufficiently distinct from Yoshino cherry to warrant recognition as a distinct entity. This study also confirmed that cherry trees in Washington, D.C. donated by Japan in 1912 are genetically distinct from king cherry trees despite the speculations by some Korean media.^[4]
• In 2016, Myong-suk Cho et al. conducted comparative phylogenetic analyses by generating the phylogeny (MP) and haplotype network (TCS) based on highly informative sequences of two cpDNA regions (rpl16 gene and trnS-trnG intergenic spacer). In this study, king cherry and Yoshino cherry were distinguished from each other in both the phylogeny and haplotype networks. Also it concluded that two old cherry trees in the yard of the Roman Catholic Archdiocese of Daegu which had been speculated to be king cherry transplanted from Jeju Island by Taquet are highly likely to be Yoshino cherry rather than king cherry.^[31]
• In 2016, Myong-suk Cho et al. performed the phylogenetic analysis of nrDNA ITS data and the cpDNA haplotype network analysis and suggested that independent origin between king cherry and yoshino cherry, respectively.^[32]

• In 2017, Eun Ju Cheong et al. were able to distinguish two distinct groups, king cherry and Yoshino cherry, using sequence polymorphisms in eight chloroplast DNA (cpDNA) noncoding regions. This study also revealed that the three "Korean cherry trees" which had been planted on the campus of the American University by the former South Korean president Syngman Rhee in 1943 and have been believed to be king cherry^[33] were Yoshino cherry not king cherry.^[34]

Putative parental species

• In 1963, Takenaka assumed that king cherry might be a hybrid between Prunus subhirtella var. pendula form ascendens (Edo higan) and Prunus quelpartensis Nakai (Tanna-yamazakura; perhaps a form of Prunus verecunda (Kasumizakura)) or some other cherry species.^[26]
• In 2014, Myong-suk Cho et al. reported that the nuclear (ITS/ETS and G3pdh) and cpDNA data, along with several morphological characteristics, provide the first convincing evidence for the hybrid origin of king cherry. The maternal parent was determined to be Prunus spachiana form ascendens (Edo higan), while the paternal parent was unresolved from the taxonomically complex Prunus serrulata (Yamazakura) / Prunus sargentii (Oyamazakura) clade.^[35]
• In 2016, Katsuki et al. proposed that king cherry have resulted from interspecific hybrid between C. itosakura (=Prunus spachiana form ascendens) and C. sargentii based on the findings by Cho in 2014 considering the possibility of hybridization from the bloom time.^[15]
• In 2017, Ara Cho et al. reported that the Sequence-level comparison of Prunus Conserved Orthologous Gene Set (Prunus COS) markers suggested that king cherry might originate from a cross between maternal P. pendula f. ascendens and paternal P. jamasakura, rather than P. sargentii.^[36]
• In 2018, Seunghoon Baek et al. analyzed the genome of king cherry using long-read sequencing and sequence phasing and found king cherry is an F1 hybrid originating from a cross between maternal P. pendula f. ascendens and paternal P. jamasakura, and it can be clearly distinguished from Yoshino cherry.^[37]
• In 2019, Myong-Suk Cho et al. using four different Rosaceae Conserved Orthologous Set (RosCOS) markers, provided evidence that king cherry originated from multiple bidirectional hybridization events between two sympatric species, P. spachiana f. ascendens as the maternal species and P. serrulata var. spontanea / P. serrulata var. quelpaertensis as the most probable paternal species.^[38]

Cultivation

As of 2017, most of the cherry trees planted in South Korea are Yoshino cherry trees known to have come from Japan or have been grafted from trees planted during the Japanese colonial period. In hopes to replace these trees with Korean native king cherry trees, efforts are undertaken to propagate the excellent varieties of king cherry.^[39]

In 1996, the Timber Breeding Research Institute, former Warm-Temperate and Subtropical Forest Research Center planted 40 king cherry trees artificially bred by the tissue culturing. They bloomed in 2003 for the first time.^[40] The Warm-Temperate and Subtropical Forest Research Center has developed a conservation area of 90,000 m² since 2000 and is now cultivating 3,000 king cherry trees. In April 2017, the center announced that it has developed 100,000 m² of king cherry tree cultivation farm at Hannam Experimental Forest and planted 4,150 four to five year old king cherry trees. The center plans to expand the area to 250,000 m² by 2022 and to cultivate a total of 20,000 king cherry trees.^[39]

Natural monument

King cherry tree habitats are designated to the Natural monument. There are three Natural monuments.

• Natural monument no. 156 – Jeju Sinrye-ri King Cherry habitat, designated in 1964.^{[41] [42]}
• Natural monument no. 159 – Jeju Bonggae-dong King Cherry habitat, designated in 1964. There are two king cherry trees.^{[43] [44]}
• Natural monument no. 173 - Haenam Daedunsan king cherry habitat, designated in 1966: There are two king cherry trees.^[45]
• Jeju Province Monument No. 51 - Jeju Gwaneumsa King Cherry habitat, designated in 1999.^{[46] [47]}

See also

• Cherry blossom

Notes

Note 1

Koehne described the variation of Prunus yedoensis var. nudiflora from Yoshino cherry when he proposed a new variation Prunus yedoensis var. nudiflora.^[22]

+ Variation of Prunus yedoensis var. nudiflora from Yoshino cherry
Description	Prunus yedoensis var. nudiflora	Yoshino cherry
Blade of the leaves during flowering	Up to 2,5 cm long	Less than 1 cm long
Pedicels	27–35 mm long	10–19 mm long
Sepals	Above the middle one	To the top
Petals	12.5 mm long, 11 mm wide	14–15 mm long, 12 mm wide
	Up to 7.5 mm long	Up to 6.5 mm long
	As far as the fourth part: densely softly hairy above	Medium shaggy

Note 2

According to Park Man-Kyu (1965), king cherry trees found until 1965 are as follows:^[18]

+
Year	Found by	Number of tree	Location
1908	style=text-align:left	Emile Taquet	1	Northern slope
1932	style=text-align:left	Gen-ichi Koidzumi	2 ^*1	Southern slope
1933	style=text-align:left	Yo Takenaka	1 ^*2	Southern slope
1962	style=text-align:left	Park Man-Kyu and seven others	3	Southern slope
1963	style=text-align:left	Park Man-Kyu and three others	3	Southern slope
1964	style=text-align:left	Bu Jong-hyu	1	Northern slope
1964	style=text-align:left	Park Man-Kyu and three others	3	Northern slope
Total		14

• 1According to Koidzumi, he found a king cherry and an Eishu zakura (Prunus yedoensis var. nudiflora) not two king cherry trees.^[23]

• 2According to Takenaka, the tree he observed was the same tree Koidzumi found.

^[48]

Notes and References

1. Book: Korean Red List of Threatened Species . Second . National Institute of Biological Resources . 2014 . 156 . Prunus × yedoensis Matsumura, Rosales: Rosaceae, Prunus × yedoensis is a deciduous tree endemic to Korea that only about 5 populations occur at Mt. Halla in Jeju-do. The estimated number of individuals is very small. This species is found in deciduous broadleaf forests at 450-900 m above sea level. The species is assessed as EN B2ab(iv). There are currently no regional conservation measures. .
2. Vascular Plant Diversity of Jeju Island, Korea . Kim . Chan-Soo . Korean Journal of Plant Resources . 22 . 6 . 558～570 . 2009 .
3. Web site: 한라산 전역에 왕벚나무 자생...최고 수령 265년 . King cherry tree grows all over Mt. Halla ... Oldest 265 years . April 3, 2017 . Yonhapnews . Korean.
4. Roh, M.S. . Cheong, E.J. . Choi, I-Y. . Young, Y.H. . amp . 2007. Characterization of wild Prunus yedoensis analyzed by inter-simple sequence repeat and chloroplast DNA. . Scientia Horticulturae. 114. 2. 121–128. 10.1016/j.scienta.2007.06.005. 2007ScHor.114..121R .
5. Web site: [취재후] 꽃의 전쟁...벚꽃의 원산지는?]. Flower war...Origin of Cherry tree? . Korean . KBS . April 11, 2014 .
6. Web site: 포트맥 강변의 왕벚나무도 제주도산 . King cherry around Potomac River derived from Jeju . Chosun.com . 7 February 2017 . 두 나라에서 발견된 왕벚나무는 유전적으로 동일합니다[Cherry trees found in both countries are genetically identical] . 1 May 2017 . 29 August 2017 . https://web.archive.org/web/20170829075503/http://pub.chosun.com/client/news/viw.asp?cate=C01&mcate=M1003&nNewsNumb=20170223370&nidx=23371 . dead .
7. Web site: 전국 봄꽃 축제 어디로 갈까? . National spring flower Festival, Where to go? . Dong-a Ilbo . 23 March 2017 .
8. Web site: 왕벚꽃 100년 논란 "제주가 진짜 원산지" . King cherry 100 years controversy "Jeju is the real origin" . Yonhapnews . 26 March 2017 .
9. Web site: 벚꽃 '한-일 원산지 논쟁' 왜 끝나지 않나 . Cherry "Korea-Japan origin controversy" Why does not end? . April 3, 2015 . Hankyoreh . Korean. 여의도와 진해를 포함해 우리나라 벚꽃축제의 주인공은 모두 일본이 원예종 으로 만든 왕벚나무이다. [The protagonists of Cherry Blossom Festivals in Korea including [[Yeouido]] and Jinhae are all cultivated Yoshino cherry made in Japan.].
10. Web site: [단독]여의도 화려한 벚꽃뒤엔...일본 검은 속셈 있었나 ]. Behind the brilliant Japanese cherry blossom – Dark ulterior motives? . 22 January 2008 . Segye.com . ... From 1966 until the mid-1980s, Koreans in Japan and Japanese people donated about 60,000 cherry seedlings to Jinhae City. . Korean.
11. Web site: 때되면 한-일 원산지 논쟁, 벚꽃에게 물어봐! . Korea-Japan Origin debate. Ask cherry! . April 3, 2015 . The Hankyoreh .
12. Botanical Magazine (Tokyo) . 15 . 174 . 1901 . Cerasi Japonicæ duæ Species novæ . Latin . 99–101 . Jinzō . Matsumura. 10.15281/jplantres1887.15.174_99 . free .
13. Wilson . E. H. . 1916 . The Cherries of Japan . 16 . Publications of the Arnold Arboretum . 7 . To me P. yedoensis Matsumura strongly suggests a hybrid between P. subhirtella, var. ascendens Wilson and the wild form of P. Lannesiana Wilson. It has many characters of the latter and in its venation, pubescence and shape of the cupula resembles the former. .
14. 日本產サクラ屬の學名に就いて . Nomenclature of Cerasus in Japan . Masamune, Genkei . Genkei Masamune . Suzuki, Shigeyoshi . 316–318 . 台北農林学会報 [Journal of Taihoku society of Agriculture and Forestry] . 1 . 3 . 1936 . Prunus × yedoensis (Matsum.) Masam. & Suzuki .
15. Nomenclature of Tokyo cherry (Cerasus × yedoensis 'Somei-yoshino', Rosaceae) and allied interspecific hybrids based on recent advances in population genetics . Katsuki . Toshio . etal . Taxon . 65 . 6 . December 2016 . 1415–1419 . 10.12705/656.13.
16. Web site: 진해군항제에 부치는 벚꽃 단상 . Jinhae naval port festival and random thoughts . April 2, 2007 . An . Byeong-gyu . 제주도 왕벚꽃이란 이름도 오래된 것은 아니다. 육지학자들이 현지 답사에 나선 1963년도에 처음으로 지은 것이라 한다. 그때까지는 '털벚나무'나 '사쿠라'로 표기하고 있다. [The name "king cherry" is also not old. It was named in 1963 for the first time when scholars conducted a field survey. Until then, it was called "hairy cherry" or "sakura".] . Gyeongnam Sinmun .
17. 소메이요시노, 왕벚나무, 벚꽃놀이 - 역사ㆍ문화와 과학의 관계 맺기 - [Yoshino cherry, King cherry, Cherry blossom viewing - Establishing the relationship between history/culture and science -] ]. Comparative Japanology . 34 . September 2015 . Mun Man-yong . 당시까지 왕벚나무라는 우리말 이름은 없었고, 사쿠라나무, 털벚나무 등으로 불렸다. 도봉섭, ｢조선산식물의 분류 (中)｣, 「동아일보」 1936. 4. 21. [Until then, there was no Korean name for king cherry, and it was called ''sakuranamu'' (sakura tree), '' teolbeonnamu'' (hairy cherry tree), and so on. Do Bong-seop, "Classification of Korean Plant (Second)", "Dong-A Ilbo" 1936. 4. 21] .
18. 한국 왕벚나무의 조사연구사 . Research study history of King cherry in Korea . Man-Kyu . Park . Journal of Plant Biology . 1965 . 8 . 3 . 12–15 . Korean .
19. Web site: [한라칼럼]왕벚나무의 선각자들 ]. [Halla column] The forerunners of the King cherry tree . Halla Ilbo . April 13, 2011 .
20. Wild Prunus yedoensis and its putative parent in Mt. Halla (II) . 한라산 자생 왕벚 및 추정양친에 관한 연구 (II) . Chang-yeol . Han . 1965 . Korea Journal of Botany . 8 . 1 . 11–18 . Korean. Wild cherry trees which grow wild in Mt. Halla and whose blooming season is April are mostly P. subhirtella var. pendula form. ascendens and P. donarium P. yedoensis is rare in number, around 10 individuals, having been found in a half century..
21. Web site: Molecular Phylogeny of the Genus Prunus in Korea and Japan Inferred from Nuclear Ribosomal and Chloroplast DNA Sequences . Yong-hwan . Jung . December 2001 . Department of Biology Graduate School, Cheju National University . A Dissertation Submitted in Partial Fulfillment of the Requirements for the Degree of DOCTOR OF PHILOSOPHY
22. Koehne . Von E. . 95 Prunus yedoensis var. nudiflora, nov. var. . Repertorium Specierum Novarum Regni Vegetabilis . 10 . 30–32 . 507 . 1912 . 10.1002/fedr.19120103013.
23. 雑録 – 染井吉野桜の天生地分明かす . Adversaria – Prunas yedoensis MATSUM. is a native of Quelpaert! . Japanese . Gen-ichi . Koidzumi . 植物分類・地理 [Acta Phytotaxonomica et Geobotanica] . 1 . 2 . 177–179 . June 1932 . ...此時以來ソメヰヨシノザクラは濟州島に自生すと誤り傳へられ,... ... されば現今ソメヰヨシノザクラの原産地は濟州島なり。... . 2017-03-28 . 2017-03-29 . https://web.archive.org/web/20170329141556/http://jboli.c.u-tokyo.ac.jp/~jsps/pdf/1(2)/110003760559.pdf . dead .
24. Gen-ichi . Koidzumi . 白瀧桜と緑吉野桜 . Shirataki zakura and Midori yoshino zakura . 植物分類・地理 [Acta Phytotaxonomica et Geobotanica] . 2 . 2 . 139–140 . 1933 . ...大和吉野の白瀧櫻は濟州島のタンナヤマザクラ（予のエイシウザクラ）(Prunus quelpaertensis Nakai) (=Prunus nudiflora Koidz. Pro parte) ....
25. Web site: 제주벚나무. Jeju cherry . Korea National Arboretum .
26. Yo . Takenaka . The Origin of the Yoshino cherry tree . Journal of Heredity . 54 . 5 . 207–211 . 1963 . I visited the (Quelpart) island in 1933 and observed that the tree, which was growing wild, showed differences from P. yedoensis; the hairs on calyx lobes and on the lower side of leaves were less numerous, and the peduncles were shorter. I concluded that it could not be P. yedoensis. I assumed that it might be a hybrid between P. subhirtella var. pendula form ascendens (Edo higan) and Prunus quelpaertensis (Tanna-yamazakura; perhaps a form of P. verecunda) or some other cherry species . 10.1093/oxfordjournals.jhered.a107250.
27. Analyses of Clonal Status in 'Somei-yoshino' and Confirmation of Genealogical Record in Other Cultivars of Prunus × yedoensis by Microsatellite Markers . Iketani, Hiroyuki. Breeding Science . 57 . 1–6 . 2007 . natural hybridization either in the Izu peninsula, on Izu-oshima Island or on Cheju-do Island in Korea, although the possibility of the latter location was ruled out by Takenaka (1962) . etal . 10.1270/jsbbs.57.1. free .
28. Phylogenetic Relationships of Prunus（Rosaceae）in Korea and Japan Inferred from Chloroplast DNA Sequences . Yong-Hwan. Jung . Korean Journal of Genetics . 27 . 4 . 279–288 . December 2005 . etal . The two natives of P. yedoensis from Jeju, Korea were clearly distinguished from the cultivars as suggested in previous reports..
29. Genetic relationship of Prunus yedoensis, native and cultivar, based on internal transcribed spacer sequences of ribosomal DNA . Yong-Hwan . Jung . etal . Korean Journal of Genetics . June 1998 . 20 =issue=2 . 109–116 . The idea that P. yedoensis Matsumura-Native would be different from the P. yedoensis Matsumura-Cultivar would be strongly substantiated from the similar results obtained in this studies with those of previous studies..
30. Yong-Hwan . Jung . etal . Phylogenetic Analysis of Korean Prunus (Rosaceae) Based on ITS Sequences of Nuclear Ribosomal DNA . Gene & Genomics(former Korean Journal of Genetics 구 한국유전학회지) . 24 . 3 . 247–258 . September 2002 . A remarkable result is that the P. yedoensis wilds from Jeju ended up far from the P. yedoensis cultivars, as was proposed in a previous study based on random amplified polymorphic DNA (RAPD)..
31. Comparative phylogenetic relationship between wild and cultivated Prunus yedoensis Matsum. (Rosaceae) with regard to Taquet's collection . Korean Journal of Plant Taxonomy . 46 . 2 . 2016 . 247–255 . 10.11110/kjpt.2016.46.2.247 . Cho . Myong-Suk . etal. free .
32. The origin of flowering cherry on oceanic islands: The saga continues in Jeju Island. . Botany . 2016 . Cho . Myong-suk . etal . https://web.archive.org/web/20170402165711/http://2016.botanyconference.org/engine/search/index.php?func=detail&aid=71 . April 2, 2017.
33. Web site: Diplomacy Blossoms: The Secret History of DC's Favorite Tree . Jimmy. Hoover . April 30, 2014 .
34. Chloroplast Noncoding DNA Sequences Reveal Genetic Distinction and Diversity between Wild and Cultivated Prunus yedoensis . Eun Ju . Cheong . etal . Journal of the American Society for Horticultural Science . 142 . 6 . 434–443 . 2017 . 10.21273/JASHS.142.6.434 . free .
35. 2014 . Molecular and morphological data revealed hybrid origin of wild Prunus yedoensis (Rosaceae) from Jeju Island, Korea: Implications for the origin of the flowering cherry . American Journal of Botany . 101 . 1976–1986 . 11 . Cho . Myong-Suk . The nuclear (ITS/ETS and G3pdh) and cpDNA data, along with several morphological characteristics, provide the first convincing evidence for the hybrid origin of wild P. yedoensis. The maternal parent was determined to be P. spachiana f. ascendens, while the paternal parent was unresolved from the taxonomically complex P. serrulata/P. sargentii clade. . etal . 10.3732/ajb.1400318. 25366862 . free .
36. Genomic clues to the parental origin of the wild flowering cherry Prunus yedoensis var. nudiflora (Rosaceae) . Plant Biotechnology Reports . 11 . 6 . 2017 . 10.1007/s11816-017-0465-4 . 1–11 . Ara . Cho . 21140406 . etal .
37. Draft genome sequence of wild Prunus yedoensis reveals massive inter-specific hybridization between sympatric flowering cherries . Seunghoon . Baek . Kyung . Choi . etal . 10.1186/s13059-018-1497-y . 30180884 . 6124018 . Genome Biology . 19 . 127 . 127 . 2018 . free .
38. 10 . 2019 . Multiple Lines of Evidence for Independent Origin of Wild and Cultivated Flowering Cherry (Prunus yedoensis) . Myong-Suk . Cho. etal . 10.3389/fpls.2019.01555 . 31921231 . Frontiers in Plant Science . 1555 . 6930925 . free .
39. Web site: 한라산 자생 우수품종 왕벚나무로 일본산 대체한다 . Replace Japanese trees with the excellent varieties of king cherry trees native to Mt. Halla . April 4, 2017 . Yonhapnews .
40. Web site: [광복 70년•수교 50년 제주와 일본을 말하다/제1부 제주 왕벚의 세계화](3)대량생산 전초기지 ]. [70 years liberation, 50 years diplomatic relations: Jeju and Japan story / Part 1. Globalization of king cherry of Jeju] (3) Outpost of Mass production . Halla Ilbo . March 23, 2015. Korean .
41. Web site: 천연기념물 제156호 . Natural monument no. 156 - Jeju Sinrye-ri King Cherry habitat . Korean Cultural Heritage Administration .
42. Web site: 천연기념물 신례리 왕벚나무자생지(천연기념물 제156호) . Natural Monument sinryeri King cherry habitat (Natural Monument No. 156) . Jeju Province .
43. Web site: 천연기념물 제159호 . Natural monument no. 159 - Jeju Bonggae-dong King Cherry habitat . Korean Cultural Heritage Administration . 서로 100m쯤 떨어져 두 그루가 자라고 [Two trees are growing about 100m apart from each other] .
44. Web site: 천연기념물 신례리 왕벚나무자생지(천연기념물 제159호) . Natural Monument sinryeri King cherry habitat (Natural Monument No. 159) . Jeju Province .
45. Web site: 천연기념물 제173호 . Natural monument no. 173 - Haenam Daedunsan King cherry habitat . Korean Cultural Heritage Administration . ... 2그루의 나무가 자라고 있다. [Two trees are growing.] .
46. Web site: 제주특별자치도. 제주특별자치도청. ko. 2019-04-07. https://web.archive.org/web/20071206144259/http://www.jeju.go.kr/. 2007-12-06. dead.
47. Web site: 국가문화유산포탈 . www.heritage.go.kr. 2019-04-07.
48. Studies on the Genus Prunus, (I): The Origin of Prunus yedoensis . Botanical Magazine (Tokyo) . 75 . 889 . 278–287 . July 25, 1962 . 10.15281/jplantres1887.75.278 . 時期すでにおそく小泉博士の発見したソメイヨシノの花は終っていたが,わずかに遅れ咲ぎを一枝得た.. Takenaka . Yo . free .