Sinosenecio qii Liu & Ho (2005: 185)

Fei, Wen-Qun, Zeng, You-Pai & Yang, Qin-Er, 2023, Sinosenecio qii (Asteraceae, Senecioneae), a hitherto imperfectly known species from southern Hunan, China, Phytotaxa 616 (2), pp. 139-148 : 142-146

Sinosenecio qii Liu & Ho (2005: 185) . Figs. 1–3

Type:— CHINA. Hunan: Jianghua county , July 1960, C. J. Qi 5765 (holotype IBSC!). Fig. 1 .

Description:—Herbs, scapigerous.Rhizomes short, ca. 6 mm in diameter, clad in persistent petiole bases.Stolons absent. Stems 1(–3), scapiform, erect, slender, ca. 3 mm in diameter at base, 15–32 cm tall, glabrous. Leaves 3–7, all radical, rosulate, long petiolate; petiole ca. 5 cm long, densely arachnoid-pubescent; blade suborbicular, 5–7 cm long, 5–6 cm broad, papery, adaxially green, sparsely pubescent, abaxially greyish, sparsely pale arachnoid-pubescent, palmately 7–9-veined, apex rounded, base cordate, margin subentire, ciliate. Capitula many, arranged in 1–3 subumbelliform corymbs; peduncles 2–3 cm long, often 1-bracteate at base, rarely 1-bracteate at middle. Involucres campanulate, 3–5 mm long, 3–4 mm broad, ecalyculate; phyllaries 10–13, lanceolate, ca. 3 mm long, ca. 1.5 mm broad, apex acute, glabrous. Ray florets 8, uniseriate; corolla tube ca. 2 mm long, glabrous; lamina yellow, lanceolate, 5–6 mm long, ca. 2 mm broad, apex 3-denticulate, obtuse. Disk florets many; corolla yellow, ca. 3 mm long, tube ca. 1.5 mm long, limb campanulate; lobes oblong-lanceolate, ca. 1 mm long. Anthers oblong, ca. 1.5 mm long, basally obtuse; appendages ovate-lanceolate. Style branches recurved. Achenes cylindric, ca. 2.5 mm long, ribbed, glabrous. Pappus absent.

Phenology:—Flowering from May to June; fruiting in July.

Distribution and habitat:— Sinosenecio qii is currently known from its type locality, i.e. Jianghua county in southern Hunan province, central-southern China ( Fig. 8 ). It grows on rocks along stream sides in forests at an elevation of ca. 490 m above sea level.

Conservation status:— Sinosenecio qii , a highly locally endemic species, is currently known only from its type locality, i.e. Jianghua county in southern Hunan, China. Only approximately 50 individuals were discovered in the population. Although the type locality is not easily accessible by humans, the population seems to be somewhat under the threat of landslides caused by high precipitation. Using GeoCAT ( Bachman et al. 2011), we calculate the Extent of Occurrence (EOO) of this species to be 4 km 2 and the Area of Occupancy (AOO) to be 0.1 km 2 with a user-defined cell width of 2 km. According to the IUCN Red List Categories and Criteria ( IUCN 2012), this species should be categorized as Endangered “EN”.

Additional specimens examined:— CHINA. Hunan: Jianghua, near Xiangutan , on rocks along shady stream sides, alt. 489 m, 8 June 2022, Y. P . Zeng 600 ( IBSC) .

Notes:—The genus Sinosenecio as defined by Chen et al. (2011) comprises two major groups of species, with one having strictly polar anther endothecial cell wall thickenings and a base chromosome number of x = 30 and occurring in mountainous areas largely surrounding the Sichuan basin in southwestern China and the other having polar and radial anther endothecial cell wall thickenings and a base chromosome number of x = 24 (rarely x = 13) and largely occurring in mountainous areas in central and southern China ( Liu 2010, Chen et al. 2011, 2022, Liu & Yang 201la, b, 2012, Liu et al. 2019, Zou et al. 2020, Peng et al. 2022, Su et al. 2023a, b). It is to be noted that in Sinosenecio , the configuration of anther endothecial cell wall thickenings correlates perfectly with the base chromosome number (Liu & Yang 201la, b). The first group is currently known to consist of 16 species, including S. homogyniphyllus , the type species of Sinosenecio ( Liu 2010, Chen et al. 2011, 2022, Su et al. 2023a, b). Sinosenecio qii , having a chromosome number of 2 n = 2 x = 48 and polar and radial anther endothecial cell wall thickenings and being locally endemic to Jianghua county in southern Hunan in central-southern China, belongs to the second group, in which 32 species are currently recognized ( Liu 2010, Chen et al. 2011, Liu & Yang 2012, Liu et al. 2019, Zou et al. 2020, Peng et al. 2022). Our results, therefore, do not support Liu & He’s (2005) opinion that S. qii was closely related to S. homogyniphyllus . These two species should be only distantly related to each other, respectively belonging to different groups of species in Sinosenecio defined by Chen et al. (2011). The close affinity between S. qii and S. globiger ( Fig. 3 ) proposed by Liu (2010) and Chen et al. (2011), however, is strongly corroborated. Sinosenecio globiger has the same chromosome number of 2 n = 2 x = 48 (Liu & Yang 201la) and the same polar and radial anther endothecial cell wall thickenings (Liu & Yang 201lb) as S. qii and occurs primarily in central and southern China including Chongqiong, Guizhou, western Hubei, Hunan, Jiangxi, eastern Sichuan and northern Yunnan, and thus also belongs to the second group of species in Sinosenecio . From our results, S. qii is thus indeed confirmed to be related to S. globiger in having epappose and glabrous achenes, polar and radial anther endothecial cell wall thickenings and a chromosome number of 2 n = 48, but readily distinguishable by having scapiform (vs. leafy) stems with only radical (vs. radical and cauline) leaves subentire (vs. shallowly 3–5-lobed), and fewer ray florets (8 vs. 13).

Figures

FIGURE 1. Holotype of Sinosenecio qii.

FIGURE 2. Sinosenecio qii in the wild (China, southern Hunan, Jianghua). A. Habitat. B. Habit. C. Lower portion of an individual, showing rhizome and roots. D. Portion of stem. E. Leaf (left: adaxial side; right: abaxial side). F. Capitulum (lateral view). G. Capitulum (top view). H. Capitulum (longitudinal section). I. Phyllaries (abaxial side). J. Ray florets. K. Disk florets. L. Achenes. Photographed by You-pai Zeng.

FIGURE 3. A specimen of Sinosenecio qii (Y.P. Zeng 600; IBSC) from Jianghua in southern Hunan, China.

FIGURE 8. Distribution of Sinosenecio qii (●).