Lysimachia fanii Y.Feng Huang, W.B.Xu & L.N.Dong, 2019

Huang, Yun-Feng, Dong, Li-Na & Xu, Wei-Bin, 2019, Lysimachia fanii, a new species of Primulaceae from limestone area of Guangxi, China, PhytoKeys 130, pp. 75-84 : 75

Lysimachia fanii Y.Feng Huang, W.B.Xu & L.N.Dong sp. nov. Figs 2 , 3

Type.

CHINA. Guangxi Zhuangzu Autonomous Region: Liucheng County, Taiping Town, 23°42'50"N, 109°29'20"E, 320 m a.s.l., 21 May 2018, flowering, L.Y. Fan et al. FLY2018001 (holotype, GXMI!; isotypes, IBK!, GXMI!).

Diagnosis.

Lysimachia fanii differs from congeneric species in subgen. Idiophyton mainly by the habit being nearly rosulate, leaves congested at the apex of the rhizome, leaf blades spatulate to narrowly oblanceolate and flowers being solitary.

Description.

Herbaceous perennial, glabrous. Rhizome subterete, 6-8 cm long, 4-6 mm in diameter, branched at the apex of the rhizome. Leaves papery, thickly papery to thinly leathery when dry, spirally arranged, congested at the apex of the rhizome, ± forming a rosette, subsessile, spatulate to narrowly oblanceolate, 6-21 × 0.6-2.0 cm, tapering towards the base, apex acute to obtuse, glabrous adaxially, glandular abaxially, veins invisible on both sides. Flowers solitary, axillary. Pedicel 3.0-6.0 cm long, ca. 1 mm in diameter, densely glandular. Calyx lobes lanceolate, 5-6 × ca. 3 mm, 5 (rarely 6), separate to near the base, apex acuminate, glabrous inside, glandular outside. Corolla yellow, deeply parted, tube 0.5-1.0 mm; lobes broadly ovate, 7.0 × 6.0 mm, apex obtuse, glabrous on both sides. Filaments ca. 1.5 mm long, lower 0.5 mm connate into a tube; anthers 3-3.5 mm long, ca. 1 mm in diameter, basifixed, opening by apical pores. Ovary globose, ca. 1 mm in diameter; style 2.8 mm long, slightly shorter than stamens. Capsule globose, 3.5-4 mm in diameter.

Phenology.

Flowering from May to June.

Etymology.

The new species is named after Mr. Li-Yong Fan, who first discovered and collected this rare species.

Distribution and habitat.

Lysimachia fanii is known only from the type locality in Taiping Town, Liucheng County, Guangxi Zhuangzu Autonomous Region, China ( Fig. 4 ). It grows on moist limestone rock surfaces at the entrance to caves.

Additional specimens examined.

CHINA. Guangxi: Liucheng County, Taiping Town. 320 m a.s.l., 21 May 2018, L.Y. Fan et al. FLY2018002 (IBK, GXMI).

Taxonomic notes.

Based on the molecular phylogeny, L. fanii belongs to subgenus Idiophyton , that is also supported by the morphological characters of basifixed anthers, short filaments and anthers open by apical pores. L. fanii is morphologically similar to L. verbascifolia C.M.Hu & L.K.Phan that is endemic to limestone areas in Vietnam ( Phan and Hu 2011), but can be easily distinguished by its spatulate to narrowly oblanceolate leaf blade and glabrous adaxially and glandular abaxially. L. fanii and L. alpestris Champ. ex Benth. resemble each other in having congested leaves and spatulate to narrowly oblanceolate leaf blades and invisible veins and solitary inflorescences but L. fanii differs from L. alpestris by its rhizome which is branched at the apex without stolons from the base, leaf blade glabrous adaxially and glandular abaxially, basifixed anthers which open by apical pores. L. fanii is also similar to L. rupestris F.H.Chen & C.M.Hu from limestone areas distributed in south-western China and northern Vietnam ( Tong et al. 2017), but it can be distinguished from the latter by its rhizome which is branched at the apex and without stolons from the base, leaf blade spatulate to narrowly oblanceolate and glabrous adaxially, lateral veins invisible on both sides. A comparison of the main characters of the four species is shown in Table 2 .

Figures

Figure 2. Lysimachia fanii. A Habit B flower, frontal view C flower, back view (showing six calyx lobes) D corolla opened showing stamens E calyx and pistil F capsule. (Drawn by X. C. Qu from the holotype).

Figure 3. Lysimachia fanii. A Habitat B habit C flower, frontal view D flower, back view E flower, lateral view F stamens.

Figure 4. The distribution of Lysimachia fanii in Guangxi, China.