Prunus quanzhouensis Jian L. Li, S. H. Liang & R. H. Jiang, 2023

Liang, Sheng-Hua, Qin, Bo, Huang, Yao-Heng, Tang, Li-Ming, Zhang, Zhan-Jiang, Li, Cui, He, Ying-Hui, Jiang, Ri-Hong & Li, Jian-Ling, 2023, Prunus quanzhouensis: a newly discovered species of Prunus subgen. Cerasus (Rosaceae) from northeastern Guangxi, China, Phytotaxa 622 (4), pp. 252-259 : 253-256

Prunus quanzhouensis Jian L. Li, S. H. Liang & R. H. Jiang sp. nov. ( FIGURE 1 A–K )

Type:— CHINA. Guangxi Zhuangzu Autonomous Region, Guilin City , Quanzhou County, Tianhu National Wetland Park , 26°8′23″N, 110°51′39″E, 1500 m, 23 March 2023, Jiang R. H. et al. QZ202303001 (Holotype GXFI!), flowering stage ( FIGURE 2 ) .

Paratype:— CHINA. Guangxi Zhuangzu Autonomous Region, Guilin City , Quanzhou County, Tianhu National Wetland Park , 26°8′48″N, 110°52′00″E, 1556 m, 7 April 2023, Li J. L. et al. 2023040702 ( GXFI!), young fruit stage ; 26°8′41″N, 110°52′03″E, 1579 m, 28 April 2023, Liang S. H. et al. 2023042805 ( GXFI!), mature fruit stage .

Diagnosis:— Prunus quanzhouensis shares many similarities with P. campanulata , but there are several key differences that set it apart: the stipules are shed at a young fruit stage rather than being soon caducous during flowering; the involucral bract is abaxially glabrous and adaxially densely villous as opposed to both surfaces villous; the bract is green and is 5–6 mm long rather than brown and 1.5–2 mm long. Additionally, the number of flowers per umbel is flowered 1–3 with a diameter of 1–1.2 cm (compared to flowered 2–4, diameter 1.5–2 cm), and has triangular ovate sepals with oblique extension (as opposed to oblong and reflexed sepals). It can also be distinguished from Prunus conradinae ( Fig. 1 , L–M) by its 10–13 pairs of lateral veins on leaves (as opposed to 7–9 pairs), tubular hypanthium, ca. 9× 3 mm, wide at the top and narrow at the base (compared to tubular-campanulate, ca. 4× 3 mm, equal base and top width), sparsely pilose pedicel (vs. glabrous), and a villous style that is longer than the stamens (vs. glabrous, shorter than stamens or slightly longer). Although P. quanzhouensis shares some flower features with P. xueluoensis Nan & Wang in Nan et al. (2013), such as tubular hypanthium and triangular-ovate sepals, it can be easily distinguished by its sepals oblique extension (vs. extending at full length), sparsely pilose pedicel (vs. villous) and villous style that is slightly longer than stamens (vs. glabrous and obviously longer than stamens) ( Table 1 ). In addition, it should be noted that we can’t provide a picture comparison for P. quanzhouensis and P. campanulata , due to the lack of pictures of P. campanulata , but provide pictures of P. conradinae as contrast ( FIGURE 1 ).

Description:—Plants perennial, seasonally deciduous small trees, reaching 1.5–3.0 m tall, with blackish-brown bark. The branchlets are dark brown, the young branchlets are green and glabrous. Stipules broad linear or with deeply palmate lobes, shed at young fruit stage. Petiole 1–2 cm long, glabrous, apex with 2 circular nectaries. Leaf blade long-ovate or narrow-elliptic, papery, 2.5–7 × 1.7–2.8 cm, apex long acuminate, base slightly rounded or broadly cuneate, margin densely serrate, slightly irregular, adaxially green, abaxially pale green, both glabrous, 10–13 pairs of lateral veins. Involucral bracts brown, elliptic, ca. 7 × 4 mm, abaxially glabrous, adaxially appressed, brown, villous. Bracts green, wide flabellate, 5–6 × 4 mm, margin glandular serrate. Inflorescence umbellate, 1–3 flowered, opening before than leaves, flowers 1–1.2 cm in diameter. Peduncles very short, inconspicuous, ca. 1 mm. Pedicels 0.8–1 cm long, sparsely pilose. Hypanthium tubular, ca. 9 × 3 mm, glabrous, wide at the top and narrow at the bottom. Sepal 5, oblique upward, triangular-ovate, triangular-ovate, approximately 4.5 × 3 mm, with a mucronate apex and an entire margin, except for 1–2 cuspidate lobes at the base on both sides. Petals 5, irregularly ovate or oblong, pink, 6–8 × 5 mm, apex slightly curved inward. Stamens 30–35, 0.4–0.8 cm long, not sticking out of the corolla. Style ca. 1.5 cm long, longer than stamens, villous. Drupe round or slightly elliptic, apex flat, 8–10 × 7–9 mm, mature fruits fall easily, purplish black. Endocarp smooth, hard, ca. 6 × 4 mm.

Phenology:— Flowering in March to April and fruiting in May.

Distribution and ecology:— Prunus quanzhouensis was only known from Quanzhou County, in Guilin City, northeast Guangxi. All individuals found in the field were located in mountain areas and grow in mixed forest of evergreen and deciduous broad-leaved trees in mountain valleys at elevations of around 1500 m.

When compared with other species, fruits of P. quanzhouensis ripen faster and falls easily through the whole genus, whether it is due to the biological characteristics of this species or related to the high elevation habitat needs further research.

Etymology:— The name is derived from the type locality, Quanzhou County (Guilin City, Guangxi, China).

Vernacular name:—Ẏfflffiff (Chinese vernacular name); quán zhōu yīng huā (pronunciation in Chinese).

Conservation status:— Prunus quanzhouensis is a newly discovered species, which has been found less than 6 distribution sites in the type locality, and so far, according to our investigation, about 130 mature individuals and few seedlings have been found. Most P. qunzhouensis are grow in broad-leaved grass of steep slopes that are inaccessible, the occurrence environment is little disturbed. According to the IUCN Red List Categories and Criteria (Version 3.1) [ C2 (a)(ii)], it is temporarily assessed as Endangered ( EN) .

Figures

FIGURE 1. Prunus quanzhouensis (A–K): A. Habitat; B. Side view of flowers; C. Front view of flowers; D. Involucral bracts; E. Flowering branch; F. Petals; G. Bract; H. Villous involucral bract; I. mature fruits; J. Gynoecium; K. vertical section of flower. P. conradinae (L–M): L. Side view of flowers; M. Front view of flowers. Photographers: Jiang R.H. and Li J.L.

FIGURE 2. Distribution of Prunus quanzhouensis (★)

Tables

TABLE 1. Morphological comparisons of Prunus quanzhouensis, P. companulata, P. conradinae and P. xueluoensis.

Characters	P. quanzhouensis	P. campanulata	P. conradinae	P. xueluoensis
Stipule	broad linear or deeply palmate fissure, shed at young fruit stage	linear, soon caducous	linear to oblong-lanceolate, soon caducous after anthesis	lanceolate
Lateral veins of leaves	10–13 pairs	8–12 pairs	7–9 pairs	6–8 pairs
Involucral bract	abaxially glabrous, adaxially densely villous in the upper	both surfaces villous	abaxially glabrous, adaxially densely villous	abaxially glabrous, adaxially densely villous
Bract	green, wide flabellate, 5–6 mm long	brown, flabellate, 1.5–2 mm long	brown or green, wide flabellate, 1.3 mm long	green, obovate, spatulate, or fan-shaped, 5–7 mm long
Inflorescence	umbel, 1–3 flowered, diameter 1–1.2 cm	umbel, 2–4 flowered, diameter 1.5–2 cm	umbel, 3–5 flowered, diameter 1.5 cm	umbellate, flowered 2–4, diameter 1.5–2 cm
Hypanthium	tubular, ca. 9×3 mm, wide at the top and narrow at base	campanulate, ca. 6×3 mm, base slightly swollen	tubular-campanulate, equal width base and top, ca. 4 × 3 mm	narrow tubular, 6– 10×1.5–2.5 mm, apical enlarged
Sepal	triangular ovate, oblique extension, margin entire except for 1–2 teeth cuspidate at base on both sides	oblong, reflexed, entire	triangular ovate, extending at full length, entire	ovate-triangular, extending at full length, entire
Pedicel	sparsely pilose	glabrous or sparsely pubescent	glabrous	villous
Stamens	30–35	39–41	32–43	30–40
Style	villous, longer than stamens	glabrous, longer than stamens	glabrous, shorter than stamens or slightly longer	glabrous, obviously longer than stamens