Stellaria multipartita Bo Xu & Meng Li, 2020

Song, Yan-Feng, Li, Meng, Xu, Bo, Chen, Shui-Fei, Chen, Lin & Xie, Chun-Ping, 2020, Stellaria multipartita (Caryophyllaceae), a new species from Chongqing, China, Phytotaxa 442 (3), pp. 196-204 : 198-202

Stellaria multipartita Bo Xu & Meng Li sp. nov. ( Figs. 2 & 3 )

Type:— CHINA. Chongqing: Wushan county, Dangyang town , Congping , in forest, 2041 m, 110°02’01”E, 31°23’38”N, 4 August 2019, Meng Li 00785 (holotype NF2007616 !; isotypes CDBI!, NF2007617 !) .

Diagnosis:— Stellaria multipartita is similar to S. radians from which differs in having annual habit (vs. perennial), oblong-triangular to ovate-triangular leaves (vs. oblong-lanceolate to ovate-lanceolate), 10–12-cleft petals (vs. 5–7- cleft) and mamillate seeds ornamentation (vs. scrobiculate) ( Fig. 4 ). Moreover, it is similar to S. sessiliflora by the mamillate seed ornamentation, but these two species differ each other by habit (annual vs. perennial), leaves (oblong-triangular to ovate-triangular vs. ovate to cordate-orbicular) and petals (10–12-cleft vs. deeply bifid) ( Table 1).

Description: Herbs annual, with roots filiform. Stems 10–40 cm tall, prostrate to ascending or erect, terete, basally branched, glabrous or sparsely pubescent. Stipules absent. Leaves petioled (petiole 2–6 cm long), with blade oblong-triangular to ovate-triangular (3.5–10 × 2–5.5 cm), margin entire, apex acuminate, base obliquely cordate to reniform, abaxially midvein prominent, adaxially midvein impressed, margin shortly ciliate. Terminal or axillary solitary flowers; bracts lanceolate, herbaceous, densely lanate, pedicel 4–4.5 cm long, densely woolly, pendulous after anthesis. Sepals oblong-ovate (5–6 × 1–2 mm), outside densely lanate. Petals 5, about 1.5–2 times as long as calyx, broadly obovate-cuneate (10–13 × 7–9 mm), base clawed, 1.5–2 mm; palmately fimbriate, with 10–12 linear divisions, cleft to middle or below. Stamens 10, shorter than petals. Ovary broadly ellipsoid-ovoid; styles 3, linear. Capsule ovoid, slightly longer than persistent sepals, 6-valved to base. Seeds 2–6, black-brown, reniform, slightly compressed, mamillate with semi-rounded tubercles.

Etymology:—The specific epithet is from the Latin multi (= much), and partita (= divided).

Phenology:—Flowering time June–August, fruiting time July–September.

Distribution and habitat:— Stellaria multipartita is distributed in Wushan county and Wuxi county (Chongqing, China), where we found one population only with almost 50 individuals in mountain areas with low shrubby thickets in the margins of broad-leaved forest ( Fig. 5).

IUCN Red List category:—Due to the probably need of more extensive fieldwork, we assessed the conservation status of Stellaria multipartita as DD (Data Deficient) according to the IUCN (2019).

Taxonomic notes: — Stellaria multipartita is morphologically similar to S. radians ( Stellaria Sect. Fimbripetalum ) which differs by the several characters (see Table 1). The main characters to distinguish the two species are: habit (annual vs. perennial in S. radians ), leaves (oblong-triangular to ovate-triangular vs. oblong-lanceolate to ovate-lanceolate in S. radians ), petals (10–12-cleft to middle or below vs. usually 5–7-cleft in S. radians ), and seeds ornamentation (mamillate vs. scrobiculate in S. radians ) ( Fig. 4 & Table 1).

In comparison with Stellaria sessiliflora , which appears the species more closely related to S. multipartita from the molecular point of view, the new species differs in having annual habit (vs. perennial), oblong-triangular to ovate-triangular leaves (vs. ovate to cordate-orbicular) and much divided in petals (vs. deeply bifid) ( Table 1).

Additional specimens examined:— CHINA. Chongqing: Wuxi County, near Longwangding, in forest, 2000 m, 22 June 1958, G. H. Yang 58565 (PE00612811!).

Figures

FIGURE 2. Stellaria multipartita; A. Plant with flowers, B. Leaf margin, C. Bract, D. Flower, E. Flower lobes, F. Seed (drawing by Jing Tian).

FIGURE 3. Stellaria multipartita: A. Habit, B. Stems, C. Roots, D. Leaf and petiole, E. Flower, petals (front view), F. Flower, sepals (dorsal view), G. Seed (photos by Meng Li).

FIGURE 4. Photograph of flower, dorsal view of flower, and leaf of Stellaria multipartita (A–C) and S. radians (D–F) (photos by Meng Li & Xin-Xin Zhu).