Ranunculus maoxianensis W.Q.Fei, Q.Yuan & Q.E.Yang, 2023

Fei, Wen-Qun, Yuan, Qiong & Yang, Qin-Er, 2023, Ranunculus maoxianensis (Ranunculaceae), a new species from northwestern Sichuan, China, with an emended description of R. chongzhouensis, the putative closest ally of the new species, PhytoKeys 219, pp. 77-96 : 77

Ranunculus maoxianensis W.Q.Fei, Q.Yuan & Q.E.Yang sp. nov.

Figs 1 , 2

Diagnosis.

Ranunculus maoxianensis is similar to R. chongzhouensis in leaf blade shape and indumentum of the receptacles, carpels and achenes. However, it is easily distinguishable by having leaves adaxially puberulous with shorter appressed hairs 0.16-0.28 mm long (vs. longer appressed hairs 0.55-0.85 mm long), larger flowers (1.8-2 cm vs. 1.4-1.6 cm in diameter), larger (8-10 × 5.5-6.5 mm vs. 6-7 × 4.5-5 mm) and widely obovate petals (vs. obovate), more numerous stamens (35-55 vs. 12-18), and subglobose gynoecium and aggregate fruit (vs. ellipsoid).

Type.

China. Sichuan: Maoxian, Nanxin town, Jiuding Shan , 31°30'36.28"N, 103°46'52.01"E, alt. 3274 m, in Rhododendron forests, 7 June 2022, W.Q. Fei 565 (holotype: IBSC; isotypes: CDBI, IBSC, PE) .

Description.

Herb perennial, terrestrial. Roots fibrous, slender. Stems 25-55 cm tall when in bloom, branched, erect, sparsely puberulous. Basal leaves 2-5, long petiolate; petioles 7-20 cm long, sparsely puberulous; blades 2.2-3.2 × 3.8-5.2 cm, reniform, 3-lobed or 3-partite, herbaceous, adaxially green, appressed puberulous with hairs 0.16-0.28 mm long, abaxially light green, puberulous with hairs 0.65-1.1 mm long, base truncate or cordate, central segment 1.2-1.5 × 0.8-1.2 cm, rhombic or rhombic-obovate, margin crenulate, lateral segments 1.5-1.8 × 2-2.6 cm, obliquely flabellate, unequally 2-partite, margin crenulate. Lower cauline leaves 1-2, similar to basal ones but smaller. Upper cauline leaves 2-4, subsessile or sessile, 3-sected, segments 1.5-3 × 0.3-0.8 mm, obtriangular, lanceolate or linear, entire or 3-5-lobed. Inflorescences terminal, 4-10-flowered. Flowers 1.8-2 cm in diameter; pedicels 5-10 cm long, appressed puberulous; receptacles 3.5-4 mm long, clavate, puberulous; sepals 5, 4.6-5 × 2-3 mm, elliptic to obovate, green tinged with yellowish, adaxially glabrous, abaxially puberulous; petals 5(-6), 8-10 × 5.5-6.5 mm, widely obovate, yellow, glabrous, apex rounded or subtruncate, nectary pit without a scale, claw ca. 0.6 mm long; stamens 35-55, filaments 1.5-2 mm long, narrowly linear, anthers 1-1.2 mm long, oblong; gynoecium subglobose; carpels 16-22, ovaries ca. 0.9 × 0.8 mm, ovoid or widely ovoid, laterally flattened, biconvex, puberulous, styles ca. 0.9 mm long, glabrous, straight or apex recurved. Aggregate fruit ca. 7 × 7 mm, subglobose; achenes ca. 2.5 × 2 mm, obliquely or widely ovoid, laterally flattened, biconvex, puberulous, styles ca. 1 mm long, persistent, glabrous, straight or apex recurved.

Etymology.

The specific epithet refers to the type locality of the new species, i.e. Maoxian county in northwestern Sichuan province, China.

Phenology.

Flowering from June to July; fruiting from July to August.

Distribution and habitat.

Ranunculus maoxianensis is currently known only from its type locality, i.e., Jiuding Shan in Maoxian county, northwestern Sichuan province, China (Fig. 13 ). It grows in Rhododendron forests at altitudes of 3200-3400 m above sea level.

Conservation status.

Although Ranunculus maoxianensis is currently known only from its type locality, i.e., Jiuding Shan in Maoxian county, northwestern Sichuan province, China, our observations on living plants at its type locality revealed that this species is very common in Rhododendron forests at altitudes of 3200-3400 m above sea level. It should better be categorized as "Least Concern (LC)", following the IUCN Standards and Petitions Committee (IUCN 2022).

Additional specimens examined

(paratype). China. Sichuan: Maoxian, W.Q. Fei & H.S. Wu 397 (IBSC) .

Figures

Figure 1. Ranunculus maoxianensis sp. nov. in the wild (China, Sichuan, Maoxian) A habitat B habit C roots D portion of stem E leaf blade (left: adaxial side; right: abaxial side) F flower (lateral view) G flower (top view) H sepal (left: abaxial side; right: adaxial side) I petal (left: adaxial side; right: abaxial side) J stamens K carpels L aggregate fruit M achenes N receptacle. Photographed by Wen-Qun Fei.

Figure 2. Holotype (A) and isotype (B-D) sheets of Ranunculus maoxianensis sp. nov.

Figure 13. Distribution of Ranunculus chongzhouensis (■) and R. maoxianensis (●). Black arrow indicates the type locality of R. chongzhouensis, i. e., Chongzhou city in Sichuan province, China.