A New Species, Cerasus kumanoensis

The cherry genus Cerasus Mill. (Rosaceae) is widely distributed in the northern hemisphere. Nine species of Cerasus are native to Japan (Ka-wasaki 1993, Ohba 2001, Ikeda et al. 2017), where it has been cultivated for centuries for the aes-thetic qualities of its blossoms and where many ornamental cultivars have been reported. Inter-specific hybridization occurs relatively easily and numerous hybrid taxa have also been published in Japan. Although Japanese interest in cultivated Cerasus is so high that many studies have re-vealed morphological diversity in cultivars and hybrids (Wilson 1916, Ohwi 1953, Kawasaki 1993), in wild trees such interest has been rela-tively low and the morphological diversity within wild populations has not received much detailed examination. If Japanese wild Cerasus popula-tions are examined in detail, undescribed taxa may be found, as is the case of C. sargentii (Re-hder) H. Ohba var. akimotoi H. Ohba & Mas. Saito (Ohba & Saito 2000). Here, I describe a new species of wild cherry, C. kumanoensis, sp. nov., from the Kii Peninsula, Japan.

Cerasus jamasakura (Siebold ex Koidz.) H. Ohba, C. leveilleana (Koehne) H. Ohba and C. speciosa (Koidz.) H. Ohba are morphologically

distinct, exhibit genetic differences (Kato et al. 2014), and are treated as independent species in Japan (e.g., Ohwi 1953, Ohba 2001, Ikeda et al. 2017), although they have also been treated as va-rieties or forms of C. serrulata (Lindl.) G. Don ex Loudon (Koehne 1912, Wilson 1916, Chang et al. 2007). These three species are characterized by corymbose inflorescences with a long peduncle. Cerasus kumanoensis is considered to be close to the three species, because of its corymbose inflo-rescences and a peduncle that often extends to more than 10 mm in length during flowering. Among the species of Cerasus native to Japan, these characteristics occur only within these spe-cies.

Cerasus kumanoensis has pink petals and a short peduncle (1–4 mm long) during early blooming. It is similar to C. sargentii var. sargen-tii in appearance (Fig. 1B–E). The leaf blade on short shoots of C. kumanoensis (4–8 cm long, 1.8–3.6 cm wide) is obviously shorter and nar-rower than in C. jamasakura (5–9 cm long, 3–4 cm wide according to Kawasaki 1993), C. leveil-leana (6–12 cm long, 3–6 cm wide according to Kawasaki 1993) and C. sargentii (7–11 cm long, 4.5–6.5 cm wide according to Kawasaki 1993), as

A New Species, Cerasus kumanoensis from the Southern Kii Peninsula, Japan

tosHio KatsuKi

Tama Forest Science Garden, Forestry and Forest Products Research Institute, Todori 1833-81, Hachioji, Tokyo 193-0842, Japan. [email protected]

A new species, Cerasus kumanoensis T. Katsuki (Rosaceae), sp. nov., is described from the southern Kii Peninsula, Japan. It is similar to C. jamasakura var. jamasakura and C. leveilleana because the corym-bose inflorescences and extended peduncle are identical in these three taxa. However, C. kumanoensis is distinguished by several morphological and phenological characteristics, an earlier flowering period, narrowly ovate and smaller leaf blade (4–8 cm long, 1.8–3.6 cm wide) and glabrous petiole and pedicel.

Key words: Cerasus kumanoensis, flowering cherry, flowering period, Japan, Kii Peninsula

Acta Phytotax. Geobot. 69 (2): 119–133 (2018)doi: 10.18942/apg.201801

ISSN 1346-7565

120 Vol. 69Acta Phytotax. Geobot.

shown in Fig. 1G. The length and width of the leaf blade on the long shoots in Cerasus differ dis-tinctly from those on short shoots (Oohara 2009), and most references provide both data of long shoots and short shoots. I refer to the sizes given in Kawasaki (1993) that is based only on short shoots. Additionally, C. kumanoensis is distin-guished by its roughly serrate leaf margin (Fig. 2G) and pale green lower leaf surface (Fig. 1G), characters that in C. jamasakura are acutely ser-rate and glaucous, respectively. Cerasus kuma-noensis is similar to C. leveilleana, but is distin-guished by its glabrous petiole and pedicel (Fig. 1B, 2A, H).

Another remarkable feature of Cerasus kuma-noensis is its flowering period. Within its natural range C. kumanoensis blooms earlier than C. ja-masakura. The flowering period in 2017 of five individuals of C. kumanoensis and C. jamasaku-ra, and one cultivated plant of C. × yedoensis (Matsum.) Masam. et Suzuki 'Somei-yoshino' in the towns of Kozagawa and Kushimoto, Wakaya-ma Prefecture, are shown in Fig. 3. These indi-viduals were near each other (horizontal distance within 1,700 m, altitude 20–120 m), and the envi-ronment related to flowering period, such as the mean temperature between 11 February and 10 May in 2017 (6.6 °C), appeared to be the same. The flowering periods of C. kumanoensis and C.

jamasakura did not overlap in my observations. In individuals observed in detail, the flowering periods of surrounding individuals of the two taxa also did not overlap. As C. leveilleana blooms later than C. jamasakura (Miller-Rushing et al. 2007), C. kumanoensis and C. leveilleana also differ in flowering period and possibly do not cross with each other. Cerasus jamasakura, how-ever, blooms later in this area than in some adja-cent places. For example, in late April, when C. jamasakura blooms in Kozagawa, C. jamasakura in nearby Kamitonda has already finished flower-ing. Further studies are needed to determine the effectiveness of seasonal isolation between C. ku-manoensis and C. jamasakura.

As a result of field surveys and examination of specimens in the Makino Botanical Garden (MBK), Tokushima Prefectural Museum (TKPM), Osaka Museum of Natural History (OSA) and Wakaya-ma Prefectural Museum of Natural History (WMNH), a new taxon, Cerasus kumanoensis, was confirmed to occur only within Mie, Nara and Wakayama Prefectures. New specimens that I collected are preserved in TFA (herbarium of Tama Forest Science Garden, Forestry and Forest Products Research Institute, Japan). Since it has been thought that only C. jamasakura var. jama-sakura and C. leveilleana occur in the southern Kii Peninsula (Murata 2004, Morimoto 2011), in-

Characters C. kumanoensis C. jamasakura C. leveilleanaPeduncle length (mm) 1–4 (–10) 5–15 1–15Petal color pink (to white) white white to pinkFlowering period* Mid Mar. to early Apr. Early to mid Apr. Mid to late Apr.Bract figure obovate narrowly ovate broadly obovateFlower number per inflorescence 1–2 (–3) 2–4 2–3Leaf blade** shape narrowly ovate narrowly elliptic broadly obovateLeaf blade** length (cm) 4–8 5–9*** 6–12***

Leaf blade** width (cm) 1.8–3.6 3–4*** 3–6***

Leaf margin roughly serrate acutely serrate roughly serrateLower surface of leaf pale green glaucous pale greenPetiole and pedicel glabrous glabrous hairy* Flowering period observed in towns of Kozagawa and Kushimoto, Wakayama Prefecture, Japan, in 2017. See text.** Leaf blade observed on short shoot.*** Kawasaki (1993).

tablE 1. Comparison of characters of flowers and leaves among Cerasus kumanoensis, sp. nov., C. jamasakura var. jamasakura and C. leveilleana.

June 2018 121KatsuKi — Cerasus kumanoensis, A New Species from Japan

dividuals of Cerasus kumanoensis have often been identified as one of them (e.g. WMNH 13705 and 23483 as C. jamasakura var. jama-sakura, and OSA 240450 as C. leveilleana).

Since more than 50 names have been pub-lished among C.serrulata and related taxa from eastern Asia (Ohba 2001), the relationship be-tween them and C. kumanoensis must be exam-ined. Prunus superflua Koidz. (1932) has narrow leaf blades (6–11 cm long, 2.3–3.8 cm wide) and in general appearance is similar to C. kumanoen-sis, but the syntypes (Y. Nabeshima s.n., 15 Apr. 1932, KYO & TI; G. Koidzumi s.n., 17 May 1932, KYO) collected in Fukuoka Prefecture, Kyushu, have leaves with acutely serrate margins and nar-rowly ovate bracts, which support Ohba’s (2001) treatment of it as individual variation within C. jamasakura.

Six species, varieties or subvarieties have been published from the Kii Peninsula and its surroundings, but none of them corresponds to C. kumanoensis. Holotype specimens of Prunus mutabilis Miyoshi var. dilatata Nakai (1950) (K. Torii s.n., 30 Oct. 1949, TNS 81083) and Prunus toriwii Nakai (1953) (K. Torii s.n., 15 Apr. 1951, TNS 86156) from Aichi Prefecture have leaves with acutely serrate margins and narrowly ovate bracts. This supports Ohba’s (2001) treatment of them as representing individual variation within C. jamasakura. Makino (1906) and Makino (1928) described Prunus pseudo-cerasus Lindl. var. spontanea Maxim. subvar. humilis Makino and Prunus ogawana Makino from Kochi Pre-fecture. The narrowly elliptic leaves with acutely serrate margins of the syntypes of the former (T. Makino s.n., 1889, MAK 223123, T. Makino s.n., Jun. 1893, 223124) and the holotype of the latter (T. Makino s.n., 17 Jun. 1927, MAK 225657) sug-gest that both taxa from Kochi Prefecture are C. jamasakura as treated by Ohba (2001). A syntype of Prunus pseudo-cerasus Lindl. var. jamasaku-ra Makino subvar. pubescens Makino (1908) (S. Matsuda s.n., Apr. 1902, MAK 223105) from Nara Prefecture has broadly obovate bracts and hairy pedicels, which support Ohba’s (2001) treatment of it as a synonym of C. leveilleana. Al-though I have not seen authentic specimens of

Prunus antiqua Miyoshi (1922) from Nara Pre-fecture, it was treated as a cultivar of C. leveille-ana by Kawasaki (1993).

Taxonomic treatment

Cerasus kumanoensis T. Katsuki, sp. nov. — Figs. 1 & 2.Similar to C. leveilleana (Koehne) H. Ohba, but distin-guished by narrowly ovate and smaller leaf blades (4–8 × 1.8–3.6 cm in C. kumanoensis vs. 6–12 × 3–6 cm in C. leveilleana), earlier flowering period and glabrous peti-oles and pedicels (Table 1).

Typus. JAPAN, Honshu, Wakayama Pref., Kozagawa, Ikenoyama, alt. 40 m, 21 Mar. 2017, T. Katsuki s.n. (holo-: TI 00012970. Iso-: TFA HDA-000256–258, TNS 1284055)

Trees, deciduous, to 16 m tall (flowering well even when less than 8 m tall), DBH up to 0.3 m. Bark purplish brown, almost smooth; lenticels distinct, horizontal; young branches yellowish brown, lustrous, glabrous, extending slightly hor-izontally. Leaves alternate, reddish brown or green when young, appearing after flowering, petiolate; petiole 14–20 mm long, usually gla-brous; blade narrowly ovate, 4–8 cm long, 1.8–3.6 cm wide, base rounded to obtuse, margin sim-ply or doubly roughly serrate, serrations with an apical gland, apex caudate-acuminate, upper sur-face with sparse soft hairs, lower surface gla-brous and pale green, slightly lustrous, lateral veins 5–8 pairs, with trichomes in vein axils; api-cal part of petiole or base of blade with a pair of wart-like glands; stipules lanceolate, incised ser-rate. Bud scales sticky, outer surface glabrous, in-side with hairs. Inflorescences corymbose, 20–36 mm across, 1- or 2- (or 3)-flowered, axillary, usu-ally on previous year’s short shoots and some-times on long shoots; peduncle 1–4 mm long to sometimes over 10 mm at the end of flowering, glabrous; pedicel 6–24 mm long, usually gla-brous; bracts obovate, ca. 5 mm long, incised ser-rate with a gland. Flowers hermaphroditic; hy-panthium glabrous, reddish purple, tube campan-ulate, slightly broadened apically, 4–8 mm long; calyx lobes ovate or narrowly ovate, ca. 5 mm


0 50 mm

A B

C D E

F G

Fig. 1. Cerasus kumanoensis, sp. nov. A, shape of tree in full bloom (in Kumano on 9 Apr. 2017, TFA HAD-000288); B, hy-panthium and calyx lobes [in Kozagawa on 21 Mar. 2017, TI00012970 (holotype)]; C–E, flower (C in Kumano on 9 Apr. 2017, TFA HAD-000295, D in Kushimoto on 21 Mar. 2017, FA HAD-000213, E in Kumano on 14 Mar. 2017, TFA HAD-000190); F, mature fruit (in Kumano on 28 May 2017, TFA HAD-000295); G, leaves on short shoot (TI00012971).


Fig. 2. Cerasus kumanoensis, sp. nov. A, flower (petals removed); B, longitudinal section of flower (petals removed); C, calyx lobe; D, petal; E, bract; F, bud scale; G, margin of mature leaf (upper surface); H, leaf base and petiole; I, stone. Drawn from isotype (TNS 1284055) and para-type (TNS 1284056) by K. Hamasaki.

- 16 -

A

B

C

D

E

F

G

H

I

1mm

3mm

3mm

3mm

1mm

1mm

1mm

3mm

1mm

Fig. 2. Cerasus kumanoensis, sp. nov. A, flower (petals removed); B, longitudinal section of flower (petals removed); C, calyx lobe; D, petal; E, bract; F, bud scale; G, margin of mature leaf (upper surface); H, leaf base and petiole; I, stone. Drawn from isotype (TNS 1284055) and paratype (TNS 1284056) by K. Hamasaki.


long, margin entire or serrate, spreading at anthe-sis. Petals pink or sometimes white and slightly pink, narrowly to broadly elliptic, 10–20 mm long, 6–16 mm wide, base widely cuneate, apex emarginate. Stamens ca. 30, slightly shorter than style; filaments glabrous; pistil glabrous, 12–16 mm long. Fruits globose, glabrous, 6–8 mm across, blackish purple when mature, taste slight-ly bitter; stone flat, ovoid, 5–6 mm long.

Phenology. Coastal individuals (alt. 0–100 m) bloom earliest in late February whereas individu-als in mountainous regions (alt. 600–800 m) bloom in late April. Foliation and seed germina-tion take place slightly after flowering. Fruiting from mid May to early June.

Distribution and habitat. Cerasus kumanoen-sis is widely distributed in the southern part of the Kii Peninsula (Fig. 4). Specific localities are Hidakagawa Town, Tanabe City, Shirahama Town, Susami Town, Kushimoto Town, Kozaga-wa Town, Nachi-katsuura Town, Taiji Town, Shingu City and Kitayama Village in Wakayama

Prefecture, Kami-kitayama Village, Shimo-kita-yama Village and Totsukawa Village in Nara Pref., and Owase City, Kumano City, Mihama Town and Kiho Town in Mie Prefecture These localities are at 0 to 800 m elevation. Cerasus ku-manoensis typically grows in young secondary forests alongside other deciduous broadleaved trees. It is occurs more on ridges and slopes, less in valleys and lowlands. It is common in moun-tainous areas inland and also in coastal locations to the south.

Japanese name. Kumano-zakura. English name. Kumano cherry.

Etymology. The species epithet kumanoensis refers to old regional name of the distribution area, Kumano.

Notes. Cerasus kumanoensis is morphologi-cally distinct from C. jamasakura and C. leveil-leana. The classification of Cerasus in different parts of the world, however, is inconsistent. For example, Kuitert (1999) and Chang et al. (2007)

Fig. 3. The blossom period (dashed line) and the full blossom period (bold line) of Cerasuskumanoensis, sp. nov. (a–e), C. jamasakura (f–j) and planted C. × yedoensis ‘Somei-yoshino’ observed in 2017 at Kozagawa and Kushimoto Town, Wakayama Prefecture, Japan.

1 March 11 21 1 April 11 21 1 May 11

C. k. abcde

C. j. fghij

C. y.

- 17 -

Fig. 3. Flowering period (dashed line) and full flowering period (bold line) of Cerasus kumanoensis, sp. nov. (a–e), C. jama-sakura (f–j) and planted C. × yedoensis ‘Somei-yoshino’ observed in 2017 at Kozagawa and Kushimoto Town, Wakayama Prefecture, Japan.


do not treat Cerasus jamasakura as a species. To clarify this confusion, it is necessary to use mo-lecular methods and population genetics and to examine the nomenclature. The genetic variation within the domesticated populations of C. jama-sakura in Japan was revealed in recent years (Tsuda et al. 2009), but the relationship with C. jamasakura var. chikusiensis (Koidz.) H. Ohba on Kyushu and C. leveilleana and C. serrulata in China have not been examined. Although it is possible to identify the taxa of Cerasus in Japan using SSR markers (Kato et al. 2014), their phylo-genetic relationships have not been determined. The possibility of a hybrid origin for C. kuma-noensis must also be considered, but natural hy-brid swarms in Cerasus in Japan have not been examined genetically. Further studies are there-fore needed to determine the taxonomic classifi-

cation of these taxa, including C. kumanoensis.

Paratypes. JAPAN, Honshu, Wakayama Pref., Koza-gawa, Ikenoyama, alt. 40m. 28 Apr. 2017, T. Katsuki s.n. (TI I00012971, TFA HDA-000310–315, TNS 1284056); Hidakagawa, Sogawa, 27 Apr. 2017, T. Katsuki KMN-212 (TFA HDA-000308); Kushimoto, Mt. Kasane, 21 Mar. 2017, T. Katsuki KMN-140 (TFA HDA-000213); Na-chikatsuura, Myohozan, 22 Mar. 2016, T. Katsuki KMN-061 (TFA HDA-000028); Susami, Esumi, 8 Sep. 2016, T. Katsuki SSM-07 (TFA HDA-000172); Tanabe, Hongu, Yunomine, 29 Mar. 1994, S Yamamoto 8208 (WMNH 23483); Tanabe, Ryujin, Mitsumata-hashi, 23 May 1992, A Yamamoto s.n. (WMNH 13705); Tanabe, Ryujin, Yasui, 6 Sep. 2016, T. Katsuki RYG-10 (TFA HDA-000139); Ta-nabe, Yasukawa, 6 Sep. 2016, T. Katsuki RYG-13 (TFA HDA-000142); Mie Pref., Kumano, Fudatate Pass, 9 Apr. 2017, T. Katsuki KMN-198 (TFA HDA-000295); Kumano, Kamikawa, 14 Mar. 2017, T. Katsuki KMN-116 (TFA HDA-000190); Kumano, Kiwa, Itaya, 9 Apr. 2017, T. Kat-suki KMN-189 (TFA HDA-000288); Kumano, Kiwa, Nunobiki-no-taki, 21 Jul. 2016, T. Katsuki KMN-016

Fig.4. The locality of holotype (circle), the localities of paratype (multiplication sign) and

estimated distribution area (dashed line) of Cerasus kumanoensis, sp. nov.

- 18 -

N 30°

N 40°

E 130° E 140°

E 135° E 136° E 137°N 34°40’

N 34°00’

N 33°20’

Fig. 4. Locality of holotype (circle), localities of paratype (multiplication sign) and estimated distribution area (dashed line) of Cerasus kumanoensis, sp. nov.


(TFA HDA-000097); Owase, Hachiman tunnel, 21 Apr. 2017, K. Okuda s.n. (TFA HDA-000251); Nara Pref., Ka-mikitayama, Namegodani, 29 Apr. 2017, T. Katsuki KMN-239 (TFA HDA-000346); Totsukawa, Asahi, 30 Apr. 2017, T. Katsuki KMN-265 (TFA HDA-000368); Tot-sukawa, Seinishigawa, 3 Aug. 2006, N. Morimoto 8178-2 (OSA 240450); Totsukawa, Shiratani, 29 Apr. 2017, T. Katsuki KMN-232 (TFA HDA-000339).

I thank Ms. Y. Yamashita, Mr. T. Hogen, Mr. K. Tanoue and Mr. S. Jyoudo of the Wakayama Prefectural Forestry Experiment Station, Mr. K. Okuda and Mr. M. Nakamura of the Mie branch, Japan Tree Doctors Association, Mr. K. Jinbo and Mr. O. Hashino of the Nanki Forestry Asso-ciation, the staff of the Kozagawa Town Office, Mr. H. Sato in Kozagawa Town, the staff of the Kumano City Of-fice and Mr. K. Okada in the Wakayama Prefectural Of-fice for field surveys, Ms. A. Naito (WMNH), Mr. D. Sa-kuma (OSA), Ms. S. Fujii and Dr. K. Fujikawa (MBK), Mr. Y. Ibaragi and Mr. M. Ogawa (TKPM), Dr. H. Ikeda and Ms. A. Shimizu (TI), Dr. A. Ebihara (TNS), Dr. H. Nagamasu (KYO) and Dr. N. Murakami (MAK) for their generous support in the herbarium, and Ms. K. Hamasaki for the beautiful illustrations.

References

Chang, K. S., C. S. Chang, T. Y. Park & M. S. Roh. 2007. Reconsideration of the Prunus serrulata complex (Rosaceae) and related taxa in eastern Asia. Bot. J. Linn. Soc. 154: 35–54.

Ikeda, H., H. Iketani & T. Katsuki. 2017. Rosaceae. In: Ohashi, H. Y. Kadota, J. Murata, K. Yonekura & H. Kihara. (eds.), Wild Flowers of Japan, revised new edition 3: pp. 23–88. Heibonsha, Tokyo. (in Japa-nese).

Kato, S., A. Matsumoto, K. Yoshimura, T. Katsuki, K. Iwamoto, T. Kawahara, Y. Mukai, Y. Tsuda, S. Ishio, K. Nakamura, K. Moriwaki, T. Shiroishi, T. Gojobori & Y. Yoshimaru. 2014. Origins of Japanese flowering cherry (Prunus subgenus Cerasus) cultivars revealed using nuclear SSR markers. Tree Genet. Genomes. 10: 477–487.

Kawasaki, T. 1993. Flowering Cherries of Japan. Yama-kei Publishers, Tokyo. (in Japanese).

Koehne, E. 1912. Prunus. In: Sargent, C. S. (ed.) Plantae Wilsonianae part II: 196–282. University Press, Cambridge, Massachusetts.

Koidzumi, G. 1932. Contributiones ad Cognitionem Flo-rae Asiae Orientalis. Acta Phytotax. Geobot. 1: 164–176.

Makino, T. 1906. Observations on the flora of Japan. Bot. Mag. (Tokyo) 20: 37–45.

Makino, T. 1908. Observations on the flora of Japan. Bot. Mag. (Tokyo) 22: 93–102.

Makino, T. 1928. A contribution to the knowledge of the flora of Japan. J. Jap. Bot. 5: 11–14.

Miller-Rushing, A. J., T. Katsuki, R. B. Primack, Y. Ishii, S. D. Lee & H. Higuchi. 2007. Impact of global warming on a group of related species and their hy-brids: cherry tree (Rosaceae) flowering at Mt. Takao, Japan. Amer. J. Bot. 94: 1470–1478.

Miyoshi, M. 1922. Untersuchungen uber Japanische kirschen II. Bot. Mag. (Tokyo) 36: 1–14.

Morimoto, N. 2011. Naraken Jyumoku Bunpushi. Self-publishing. (in Japanese).

Murata, G. 2004. Kinki-chiho Shokubutsushi. Osaka Natural History Center, Osaka. (in Japanese).

Nakai, T. 1950. Contributions to knowledge of flowering plants. Bull. Natl. Sci. Mus. Tokyo 29: 71–98.

Nakai, T. 1953. Opera phytologica novissima. Bull. Natl. Sci. Mus. Tokyo 33: 1–30.

Ohba, H. 2001. Cerasus. In: Iwatsuki, K., D. E. Boufford & H. Ohba (eds.), Flora of Japan vol. IIb , pp. 128–144. Kodansha, Tokyo.

Ohba, H. & M. Saito 2000. A new variety of Cerasus sar-gentii (Rehder) H.Ohba found at Mt. Shiraiwa-yama, Miyazaki Prefecture, Kyushu, the southern limit of distribution of the species. J. Jap. Bot. 75: 370–371.

Ohwi, J. 1953. Flora of Japan. Shibundo, Tokyo.Oohara, T. 2009. The Handbook of Flowering Cherries in

Japan. Bun-ichi Co., Ltd., Tokyo. (in Japanese).Tsuda, Y., M. Kimura, S. Kato, T. Katsuki, Y. Mukai & Y.

Tsumura. 2009. Genetic structure of Cerasus jama-sakura, a Japanese flowering cherry, revealed by nu-clear SSRs: implications for conservation. J. Pl. Res. 122: 367–375.

Wilson, E. H. 1916. The Cherries of Japan. University Press, Cambridge, Massachusetts.

Received June 18, 2017; accepted January 1, 2018

Documents

A New Species, Cerasus kumanoensis