Campanula luzhijiangensis Huan C. Wang & T. T. Wang, 2022

Wang, Ting-Ting, Dang, Zeng-Yan, Yang, Feng & Wang, Huan-Chong, 2022, Campanula luzhijiangensis (Campanulaceae), a new species from Yunnan, southwest China, PhytoKeys 206, pp. 49-59 : 49

Campanula luzhijiangensis Huan C. Wang & T. T. Wang sp. nov.

Figs 1 , 2 , 3

Type.

China. Yunnan Province: Yimen County, Luzhi Town, Luzhijiang Valley , Xiaoluzhi , 24°40'53"N, 101°58'19"E, elev. 1450 m, 25 September 2021, H. C. Wang et al. YM15319 (holotype YUKU!, isotypes YUKU!) .

Diagnosis.

Campanula luzhijiangensis is most similar to C. mekongensis Diels ex C. Y. Wu, but clearly distinguished from the latter by its stems with numerous leaf scars at base, leaves usually oblanceolate, relatively small, 0.3-2.0 cm long, 0.1-0.3 (- 0.5) cm wide, margin subentire or sparsely crenate, slightly recurved, hypanthium densely villous throughout, calyx lobes usually ovate, 1-2 mm long, 1.0-1.5 mm wide, corolla tubular-campanulate, tube 2-4 mm in diameter. In contrast, C. mekongensis has stems without leaf scars at base, leaves oblong, narrowly obovate or oblanceolate, 0.5-3.0 cm long, 0.3-1.2 cm wide, margin not recurved, serrate, hypanthium only hispid along ribs, calyx lobes subulate, 2-4 mm long, less than 1 mm wide, corolla campanulate, tube 6-10 mm in diameter.

Description.

Herbs perennial, caespitose. Rootstock woody, naked, with numerous ascending stems. Stems polyphyllous, usually simple at base, rarely branched, slightly lignified, purplish, densely white villous, 10-30 cm long. Leaves alternate, sessile or subsessile, basal leaves withering or caducous; blades usually oblanceolate, rarely elliptic, 0.3-2.0 cm long, 0.1-0.3 (-0.5) cm wide, abaxially densely villous, adaxially appressed pubescent, apex obtuse to acute, margin subentire or sparsely crenate, slightly recurved, base cuneate. Inflorescences terminal, thyrsiform; rachis and branches gracile, indumentum similar to that of the stems; bracts oblanceolate, lanceolate to linear, 0.1-0.2 cm long, 0.7-0.9 mm wide. Flowers erect or ascending, rarely reflexed; pedicels gracile, villous, 0.5-1.0 cm long, 0.2-0.3 mm in diameter; hypanthium obconic, longitudinally ribbed, densely spreading villous, base cuneate, calyx lobes ovate, 1-2 mm long, 1.0-1.5 mm wide at base, acute to acuminate at apex, margin slightly reflexed, serrulate. Corolla blue, blue-white or lilac, tubular-campanulate, 5-10 mm long, externally pubescent, internally glabrous; tube subconic, 4-8 mm long, 2-4 mm in diameter; corolla lobes ovate to ovate-lanceolate, or nearly oblong, 2.5-7.0 mm long, acute at apex. Stamens 5, included, shorter than style; filaments ca. 3 mm long, base dilated into flakes, dilated part nearly elliptic, densely villose, connivent around the style at the anthesis; anthers clavate, ca. 2 mm long, light yellow. Style slightly exserted, ca. 6 mm long, base glabrous, middle and lower part with hairs, upper part papillose; stigma 3-fid, 1.0-1.3 mm long. Capsule obconic, 3-poricidal toward base, apical calyx lobes persistent. Seed elliptic, shiny, 0.4-0.5 mm long, 0.2-0.3 mm wide.

Phenology.

Campanula luzhijiangensis has a relatively long flowering period; it usually flowers from August to January of the following year, and fruits from September to February.

Etymology.

The specific epithet luzhijiangensis is derived from the type locality of the new species, the Luzhijiang Valley, and the Latin suffix ensis, indicating the place of origin or growth.

Habitat and distribution.

Campanula luzhijiangensis appears to be a rare species endemic to Yunnan, southwest China. It is only known from the type locality in the valley of the Luzhijiang River, an upper tributary of the Hong (Red) River that flows from Yunnan in southwest China through northern Vietnam to the Gulf of Tonkin (Fig. 4 ). The climate in Luzhijiang Valley is semi-dry and hot, with an annual average temperature of 21.0 °C and a total annual precipitation of 822.8 mm. Campanula luzhijiangensis usually occurs in the rock crevices, xerophilous scrubs or grasslands between 1250 and 1500 m elevation. Associated vegetation includes Phyllanthus emblica Linn. ( Phyllanthaceae), Paliurus orientalis (Franch.) Hemsl. ( Rhamnaceae), Dalbergia yunnanensis Franch. ( Fabaceae), Symphoricarpos sinensis Rehd. ( Caprifoliaceae), Duhaldea lachnocephala Huan C. Wang & Feng Yang ( Asteraceae) (an endemic species described by Yang et al. (2022)), Pterygiella luzhijiangensis Huan C. Wang ( Orobanchaceae), Silene otodonta Franch. ( Caryophyllaceae), Spodiopogon sagittifolius Rendle ( Poaceae), Heteropogon contortus (Linn.) Beauv. ex Roem. et Schult. ( Poaceae) and Themeda caudata (Nees ex Hooker et Arnott) A. Camus ( Poaceae).

Conservation status.

Campanula luzhijiangensis is a rare species with a restricted distribution and small population size. Currently, it is only known from a single locality in the Luzhijiang River Valley in the Yimen County, southwest China, where the estimated area of occupancy (AOO) is less than 20 km2. The total population size is estimated to be fewer than 500 mature individuals. Following the IUCN guidelines ( IUCN 2012, 2022), this new species should be classified as Vulnerable [VU (D1, D2)].

Figures

Figure 1. Campanula luzhijiangensis A habit B adaxial surface of leaf C abaxial surface of leaf D flower E style and stamens F style G stamen H seed.

Figure 2. Campanula luzhijiangensis A, B habit C plants in fruiting stage D plants in flowering stage E adaxial surface of leaf F abaxial surface of leaf G flower (side view).

Figure 3. Campanula luzhijiangensis A adaxial surface of bract B abaxial surface of bract C flower (side view) D corolla dissected E stamens and pistil F style, stamens and dissected hypanthium G stamen H seed.

Figure 4. Geographical distribution of Campanula luzhijiangensis (red dot).