Sorbus fruticula R.Li & McAllister, 2025

Li, Rong, 2025, A new species of Sorbus (Rosaceae) from western Yunnan, China, Phytotaxa 693 (1), pp. 95-100 : 96

Sorbus fruticula R.Li & McAllister , sp. nov. ( Figs. 1 , 2 ).

Type: — CHINA. Yunnan: Nujiang Lisu People Autonomous Prefecture, Gongshan County, Cikai Township , E side of Gaoligong Shan , W of Gongshan and W of Qiqi between Dongshao Fang and the pass to the Dulong Jiang valley , open alpine scrub and boggy meadows, growing in closed shrub vegetation on an exposed ridge, elev. 3600–3680 m, 27°41′46″N, 98°27′19″E, 16 July 2000, Heng Li with Bruce Bartholomew, Philip Thomas, Peter Fritsch, Zhiling Dao, Zhonglang Wang and Rong Li 12662 (holotype KUN! barcode 1415560; isotypes E! barcode E00416532 , CAS! barcode 325679) .

Diagnosis: —It is similar to S. poteriifolia Handel-Mazzetti (1925: 223) , but can be distinguished by its stature, being up to 1 m (vs. less than 20 cm) and its non-rhizomatous growth habit (vs. rhizomatous). Additionally, S. fruticula has petals that are pink in the distal half, whereas S. poteriifolia exhibits pink coloration in less than the distal half of the petals. The styles of S. fruticula are basally glabrous, in contrast to the pubescent styles of S. poteriifolia .

Shrubs small, 0.1–1.0 m tall, non-rhizomatous; Branchlets terete, dark grayish brown or grayish purple, with indistinct elliptic lenticels, reddish brown pubescent when young, glabrous or subglabrous when old; buds red, ovoid, 3–4 mm, apex acute; scales several, dark purple, reddish brown pubescent at tip and margin. Leaves imparipinnate, 6–11 × 3.8–4.5 cm in length and breadth with petiole 1.2–2.5 cm long; stipules lanceolate or linear, 5–8 mm long, herbaceous, slightly reddish brown pubescent; rachis sulcate, slightly winged, reddish brown pubescent when young, subglabrous when mature; leaflet blades 4–7 pairs, at intervals of 7–10 mm, elliptic or oblong-elliptic, 11–21 × 5–11 mm, apex acute or obtuse, base obliquely rounded, margin sharply serrate, entire only at base, shiny dark green adaxially, pale green abaxially, red at base where joined to rachis, both surfaces glabrous. Inflorescences corymbose or compound corymbose, 3–4.5 × 2.5–3 cm, 10–12 flowered; rachis and pedicels reddish brown pubescent; bracts linear, 2–3 mm long, slightly reddish brown pubescent. Pedicel 1–2 mm long. Flowers ca. 12 mm in diameter; hypanthium campanulate, glabrous; sepals triangular, 1–1.5 mm long, more or less translucent with midrib evident, apex acute; petals ovate, 3–4 × 2.5–3.5 mm, pink with white at base, adaxially pilose, apex obtuse; stamens 20, ca. 1/2 as long as petals, anthers ovoid; styles 4 or 5, shorter than or nearly as long as stamens, ca. 1.5–1.75 mm long, glabrous. Fruit globose, 6–8 mm in diameter, initially dull crimson-brown, ripening to white flushed pink, eventually losing pinkish color and becoming pure white but blackish around sepals; sepals persistent, erect, very ‘open’ in larger fruits with carpel tops visible within, sinuses between sepals wide and u-shaped; seed ca. 4.5 × 2.5 mm, chestnut brown.

Distribution and habitat: — Sorbus fruticula is currently known only from three locations in the Gaoligong Mountains, Gongshan County, Yunnan Province, China. It inhabits in alpine thickets on rocky slope at elevation ranging from 3,530 –3,930 m.

Conservation status: — The species has been collected solely from the type locality and is presumed to be rare. According to the IUCN red list categories and criteria ( IUCN Standards and Petitions Committee 2022), Sorbus fruticula is assessed as ‘Endangered’ ( EN) based on the following criteria: criterion B2 , its known area of occupancy is less than 500 km 2 ; criterion C: the total population size is estimated to be fewer than 2,500 mature individuals.

Phenology: — Sorbus fruticula was observed with flowers from June to July and with fruits from August to October.

Etymology: —The specific epithet fruticula refers to its usually dwarf shrubby habit.

Vernacular name: —‘ḝffiṯ¨’ (Ai Sheng Hua Qiu) in Chinese.

Additional specimens examined (paratypes): — CHINA. Yunnan: Nujiang Lisu People Autonomous Prefecture, Gongshan County, Cikai Township, E side of Gaoligong Shan, W of Gongshan and W of Qiqi between Dongshao Fang and the pass to the Dulong Jiang valley, open alpine scrub and boggy meadows, growing in closed shrub vegetation on an exposed ridge, elev. 3600–3680 m, 27°41′46″N, 98°27′19″E, 16 July 2000, Heng Li with Bruce Bartholomew, Philip Thomas, Peter Fritsch, Zhiling Dao, Zhonglang Wang and Rong Li 12661 ( KUN!, E!, CAS!); Dulongjiang Township, N side of the pass above the tunnel on the road between Gongshan and Kongdang, W side of Gaoligong Shan, bamboo and Rhododendron thicket with adjacent meadow areas, growing in thin humus-rich soil over granite with other small shrubs of Rhododendron and Gaultheria , elev. 3530 m, 27°46′20″N, 98°26′48″E, 02 October 2002, Heng Li with Zhiling Dao, Rong Li, Yunheng Ji, Benxi Liu, Peter Fritsch, Bruce Bartholomew, Mark Waston and David Knott 16887 ( KUN!, E!, CAS!); Bingzhongluo Township, about 3 direct km S of Gawagapu mountain and ca. 15 direct WSW of Bingzhongluo in the next basin to the E of Chukuai lake, E side of Gaoligong Shan, high elevation meadow along rocky slope, growing on rocky slope, elev. 3930 m, 27°58′58.8″N, 98°28′52.9″E, 20 August 2006, Heng Li with Zhiling Dao, Yunheng Ji, Yitao Liu, Guangwan Hu, Xiaohua Jin, Peter Fritsch, Catherine Buch and Simon Crutchey 31280 ( KUN!, E!, CAS!); Bingzhongluo Township, about 3 direct km S of Gawagapu mountain and ca. 16 direct WSW of Bingzhongluo in the next basin to the E of Chukuai lake, E side of Gaoligong Shan, alpine meadow, growing on slope, elev. 3770 m, 27°59′2.1″N, 98°28′13.6″E, 29 August 2006, Heng Li with Zhiling Dao, Yunheng Ji, Yitao Liu, Guangwan Hu, Xiaohua Jin, Peter Fritsch, Catherine Buch and Simon Crutchey 31579 ( KUN!, E!, CAS!).

Figures

FIGURE 1. Sorbus fruticula. A. Flowering branch. B. Fruiting branch. C. Flower, longitudinal section. D. Fruit, cross section. E. Fruit, longitudinal section. Drawn by Ling Wang from the holotype.

FIGURE 2. Sorbus fruticula. A. Habit. B. Flowering branch. C. Fruiting branch.