Ranunculus jiguanshanicus (Ranunculaceae), a new species from Sichuan, China Author Fei, Wen-Qun https://orcid.org/0000-0001-9942-2120 Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510655, Guangdong, China & University of Chinese Academy of Sciences, Beijing 100049, China Author Yuan, Qiong https://orcid.org/0000-0003-2613-5045 Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510655, Guangdong, China & Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510655, Guangdong, China yuanqiong@scbg.ac.cn Author Yang, Qin-Er https://orcid.org/0000-0002-6261-0731 Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510655, Guangdong, China & Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510655, Guangdong, China text PhytoKeys 2023 2023-01-25 219 57 75 http://dx.doi.org/10.3897/phytokeys.219.96266 journal article http://dx.doi.org/10.3897/phytokeys.219.96266 1314-2003-219-57 5C8EFFD99E5352459F5DA3E390091C35 Ranunculus jiguanshanicus W.Q.Fei, Q.Yuan & Q.E.Yang sp. nov. Figs 1 , 2 , 3 , 4 , 5 Diagnosis. Ranunculus jiguanshanicus is readily distinguishable from all other Chinese species of Ranunculus by a unique array of characters, including small stature, glabrous and prostrate stems, 3-foliolate leaves with obvious petiolules (3-5 mm long), unequally 3-sected leaflets, lanceolate to linear ultimate leaflet segments, small flowers (5.2-6 mm in diameter), and long styles in the carpels and achenes (ca. 0.8 mm long). Type . China . Sichuan province : Chongzhou , Anzihe Nature Reserve , Jiguan Shan , 30°46'5.8"N , 103°10'21.93"E , alt. 2998 m , among moss on rocks or rocky cliffs in moist places in fir forests, 10 June 2022 , W.Q. Fei 581 ( holotype : IBSC; isotypes: IBSC, PE) . Description. Herbs perennial, terrestrial or rupicolous. Roots 2-5, 6-10 cm long, fibrous, slender, slightly thickened at base. Stems 7-15 cm long, prostrate, glabrous, unbranched to few-branched. Basal leaves 2-5, 3-foliolate, long-petiolate; petioles 2-4 cm long, glabrous; blades 0.8-1 x 0.8-1.3 cm, suborbicular, thinly chartaceous, adaxially green, abaxially light green, both sides glabrous; leaflets 3, unequally 3-sected, petiolulate, petiolules 3-5 mm long, ultimate leaflet segments 3-4 x 0.8-1.2 mm, narrowly lanceolate to linear, margin entire, apex 1-2-denticulate to 1-2-cleft. Lower cauline leaves 2-3, similar to basal ones but smaller. Upper cauline leaves 1-2, 3-foliolate, subsessile or sessile, adaxially glabrous or sparsely puberulous, abaxially glabrous, central leaflet 4.5-5 x 1-1.2 mm, narrowly lanceolate to linear, margin entire, lateral leaflets entire, 1-2-lobate or 2-3-sected, ultimate leaflet segments 3-3.5 x 1-1.2 mm, narrowly lanceolate to linear. Inflorescences terminal, 1(-2)-flowered. Flowers 5.2-6 mm in diameter; pedicels 1-2 cm long, glabrous or sparsely puberulous; receptacles ca. 1.2 mm long, clavate, glabrous; sepals 5, 2.2-2.5 x 1.5-1.8 mm, elliptic to obovate, patent, green tinged with yellowish, concave, both sides glabrous; petals 5(-6), 3.2-3.5 x 1.8-2 mm, obovate, yellow, glabrous, apex rounded, nectary pit without a scale, claws ca. 0.4 mm long; stamens 6-8, ca. 2 mm long, filaments ca. 1.5 mm long, narrowly linear, anthers ca. 0.5 mm long, oblong; gynoecium subglobose; carpels 8-12, ovaries ca. 0.8 x 0.6 mm, ovoid, laterally flattened, biconvex, glabrous, styles ca. 0.8 mm long, glabrous, apex recurved. Aggregate fruit ca. 4 x 4.2 mm, subglobose; achenes ca. 1.2 x 1 mm, widely ovoid, laterally flattened, biconvex, glabrous, styles ca. 0.8 mm long, persistent, glabrous, apex recurved. Etymology. The specific epithet refers to the type locality of the new species, i.e. Jiguan Shan in the Anzihe Nature Reserve in Chongzhou, Sichuan province, China. Phenology. Flowering in early June; fruiting at the end of June. Distribution and habitat. Ranunculus jiguanshanicus is currently known from its type locality, i.e., Jiguan Shan in the Anzihe Nature Reserve in Chongzhou, and from the closely adjacent Xiling Xue Shan in Dayi, both in Sichuan province, China (Fig. 6 ). It grows among moss on rocks or rocky cliffs in moist places in fir forests at altitudes of 2900-3150 m above sea level. Conservation status. Ranunculus jiguanshanicus is currently known only from two populations in Sichuan province, China. The Chongzhou population consists of ca. 150 individuals within an area of less than 10 m2. The size of the Dayi population remains unknown. The conservation status of R. jiguanshanicus should better be categorized as "Data Deficient (DD)" before adequate information of this species is acquired ( IUCN Standards and Petitions Committee 2022 ). Discussion. Ranunculus jiguanshanicus is readily assigned to R. sect. Ranunculus due to its swollen achenes with a distinct beak and receptacles hardly enlarged after anthesis. In his infrageneric classification of the Chinese Ranunculus , Wang (1995a , b ) placed almost all the alpine species within this section under the name R. sect. Auricomus (Spach) Schur. Morphologically, Ranunculus jiguanshanicus is somewhat similar to R. pegaeus (Figs 7 - 10 ), also a member of R. sect. Ranunculus , in having prostrate and glabrous stems (Figs 2A, B , 8A, B ), small flowers (Figs 3D , 9D ), subglobose aggregate fruit (Figs 3I , 9I ), and glabrous carpels (Figs 3H , 9H ), achenes (Figs 3G , 9G ) and receptacles (Figs 3K , 9K ). However, it differs by having 3-foliolate leaves with obvious petiolules (3-5 mm long), unequally 3-sected leaflets, lanceolate to linear, entire or 1-2-denticulate to 1-2-cleft ultimate leaflet segments (Fig. 3C ), and styles in the carpels and achenes ca. 0.8 mm long (Fig. 3H, G ). In R. pegaeus , the leaves are 3-partite, 3-sected or 3-foliolate with the central segment/leaflet rhombic or oblong, entire or 3-denticulate and the lateral segments/leaflets obliquely flabellate, entire or unequally 2-cleft (Figs 9C , 10 ), and styles in the carpels and achenes ca. 0.3 mm long (Fig. 9H, G ). A detailed morphological comparison between R. jiguanshanicus and R. pegaeus is given in Table 1 . Figure 2. Ranunculus jiguanshanicus sp. nov. in the wild A, B habitat C habit. The left plant (at fruiting stage) in B photographed by De-Chang Meng from Xiling Xue Shan in Dayi, Sichuan province, and the right two plants (at flowering stage) photographed by Wen-Qun Fei from Jiguan Shan in the Anzihe Nature Reserve in Chongzhou, Sichuan province. Figure 3. Ranunculus jiguanshanicus sp. nov. in the wild A roots B portion of stem C leaves D flower (lateral view) E flower (top view) F sepal (left: abaxial side; right: adaxial side) G petal (left: adaxial side; right: abaxial side) H stamens I carpels J aggregate fruit K achenes L receptacle. A-H photographed by Wen-Qun Fei from the population on Jiguan Shan in Chongzhou, Sichuan province and I-L photographed by De-Chang Meng from the population on Xiling Xue Shan in Dayi, Sichuan province. Table 1. Morphological comparison of Ranunculus glareosus , R. jiguanshanicus sp. nov. and R. pegaeus .

-	R. glareosus	R. jiguanshanicus	R. pegaeus
Roots	2-5, more than 15 cm long	2-5, 6-10 cm long	5-10, 8-12 cm long
Stems	sparsely puberulous	glabrous	glabrous
Basal leaves	3-sected or 3-foliolate, fleshy, adaxially glabrous or sparsely puberulous, abaxially glabrous, central segment/leaflet ovate or rhombic, entire or 3-lobate, lateral segments/leaflets flabellate, unequally 2-partite	3-foliolate, thinly chartaceous, both sides glabrous, leaflets unequally 3-sected, with ultimate leaf segments narrowly lanceolate to linear, entire or 1-2-denticulate to 1-2-cleft	3-partite, 3-sected or 3-foliolate, thinly chartaceous, both sides glabrous, central segment/leaflet rhombic or oblong, entire or 3-denticulate, lateral segments/leaflets obliquely flabellate, entire or unequally 2-cleft
Flowers	terminal, 1-4, 15-17 mm in diameter	terminal, 1(-2), 5.2-6 mm in diameter	terminal or axillary, 3-7, 5.5-8 mm in diameter
Receptacles	3-5 mm long, clavate, glabrous	ca. 1.2 mm long, clavate, glabrous	ca. 1 mm long, clavate, glabrous
Sepals	adaxially glabrous, abaxially puberulous	both sides glabrous	both sides glabrous
Petals	9-10 x 7-8 mm, widely obovate	3.2-3.5 x 1.8-2 mm, obovate	3-3.5 x 1.5-1.7 mm, obovate
Carpels	20-35; ovaries ovoid, glabrous; styles ca. 0.2 mm long, straight	8-12; ovaries ovoid, glabrous; styles ca. 0.8 mm long, apex recurved	18-22; ovaries ovoid, glabrous; styles ca. 0.3 mm long, apex recurved
Aggregate fruit	ellipsoid	subglobose	subglobose
Achenes	widely ovoid, glabrous, styles ca. 0.2 mm long, straight	widely ovoid, glabrous, styles ca. 0.8 mm long, apex recurved	widely ovoid, glabrous, styles ca. 0.3 mm long, apex recurved

As mentioned earlier, a gathering of Ranunculus jiguanshanicus , W.B. Ju , L. Zhang & D.K. Chen AZH01290 (CDBI), from Chongzhou in Sichuan, the type locality of this species, had been previously misidentified as R. glareosus (Figs 11 - 14 ). Morphologically, R. jiguanshanicus is very easily distinguishable from R. glareosus by having glabrous stems (vs. sparsely puberulous) (Figs 3B , 13B ), thinly chartaceous leaves (vs. fleshy), leaflets of the 3-foliolate leaves with obvious petiolules (3-5 mm vs. 0.5-2 mm long), unequally 3-sected, with the ultimate leaflet segments narrowly lanceolate to linear, entire or 1-2-denticulate to 1-2-cleft (vs. 3-sected or 3-foliolate, central segment/leaflet ovate or rhombic, entire or 3-lobed, and lateral segments/leaflets flabellate, unequally 2-partite) (Figs 3C , 13C ), smaller flowers (5.2-6 mm vs. 15-17 mm in diameter) (Figs 3D, E , 13D, E ), abaxially glabrous sepals (vs. puberulous) (Figs 3F , 13F ), smaller (3.2-3.5 x 1.8-2 mm vs. 9-10 x 7-8 mm) and obovate petals (vs. widely obovate) (Figs 3G , 13G ), subglobose aggregate fruit (vs. ellipsoid) (Figs 3J , 13J ), and longer styles in the carpels and achenes (ca. 0.8 mm vs. ca. 0.2 mm long) (Figs 3I, K , 13I, K ). In habitat, R. jiguanshanicus grows among moss on rocks or rocky cliffs in moist places in fir forests at altitudes of 2900-3150 m above sea level, whereas R. glareosus grows on alpine scree slopes at altitudes of 3900-4800 m above sea level. A detailed morphological comparison between R. glareosus and R. jiguanshanicus is given in Table 1 . Figure 4. Holotype sheet of Ranunculus jiguanshanicus sp. nov. Figure 5. Isotype ( A-C ) and paratype ( D ) sheets of Ranunculus jiguanshanicus sp. nov. Figure 6. Distribution of Ranunculus jiguanshanicus sp. nov. (black square). Arrow indicates the type locality. Figure 7. Type sheets ( A, B ) of Ranunculus pegaeus . Figure 8. Ranunculus pegaeus in the wild (China, Sichuan, Maoxian) A, B habitat C habit. Photographed by Wen-Qun Fei. Figure 9. Ranunculus pegaeus in the wild (China, Sichuan, Maoxian) A roots B portion of stem C leaves D flower (lateral view) E flower (top view) F sepal (left: abaxial side; right: adaxial side) G petal (left: adaxial side; right: abaxial side) H stamens I carpels J aggregate fruit K achenes L receptacle. Photographed by Wen-Qun Fei. Figure 10. Ranunculus pegaeus . China, Sichuan, Maoxian, W.Q. Fei 569 (IBSC). Figure 11. Type sheet of Ranunculus glareosus . Figure 12. Ranunculus glareosus in the wild (China, Qinghai, Menyuan) A, B habitat C habit. Photographed by Wen-Qun Fei. Figure 13. Ranunculus glareosus in the wild (China, Qinghai, Menyuan) A roots B portion of stem C leaves D flower (lateral view) E flower (top view) F sepal (left: abaxial side; right: adaxial side) G petal (left: adaxial side; right: abaxial side) H stamens I carpels J aggregate fruit K achenes L receptacle. Photographed by Wen-Qun Fei. Figure 14. Ranunculus glareosus . China, Qinghai, Menyuan, W.Q. Fei 623 (IBSC). Additional specimens examined ( paratypes ). China . Sichuan : Chongzhou, W.B. Ju, L. Zhang & D.K. Chen AZH01290 (CDBI); Dayi, W.Q. Fei 897 (IBSC) .