Primulina sinovietnamica W.H.Wu & Q.Zhang, 2012

Wu, Wang-Hui, Meng, Tao, Xu, Wei-Bin, Liu, Sheng-Yuan & Zhang, Qiang, 2012, Primulina sinovietnamica (Gesneriaceae), a new species identified by both morphological and molecular characters from the limestone area in Guangxi, China, Phytotaxa 60 (1), pp. 32-40 : 36-38

Primulina sinovietnamica W.H.Wu & Q.Zhang , sp. nov. ( Fig. 1 & Fig. 2 A–D, H–K )

A new species similar to P. pungentisepala and P. ningmingensis , but it differs from these species in having purple villous leaf surfaces, minute bracts (<2.5 cm vs.> 5 cm), corolla small (1.2–1.8 vs. 3.0–3.5), pale purple without stripes (vs. corolla white or red with two yellow stripes) and purple (vs. white) stamen filaments.

Type: — CHINA. Guangxi: Longzhou County, Longgang National Nature Reserve . 595 m, 22°30ʹ54.03ʺ N, 106°52ʹ14.29ʺ E, 30 October 2010, Wang-Hui Wu W0321 (holotype IBK!, isotype IBK!) .

Perennial herbs. Rhizomes subterete, 2–9 × 0.5–1.6 cm. Leaves petiolate; petioles applanate, 1–4 cm long, 1–3 mm wide, appressed purple villous; leaf blade thick-papery when dry, 1.8–5 × 0.8–3 cm, elliptic, ovate to oblanceolate, appressed purple villous on both surfaces, the bases cuneate to decurrent, the margins entire, the apices acute to obtuse, lateral veins 2–4 on each side of midrib. Inflorescences cymose, 5–12 cymes per plant, axillary, 1–2-branched, 7–22-flowered; peduncle 4–10 cm long, 1.5–2.1 mm wide, scattered purple villous; bracts 2, 1.5–2.5 × 0.3–0.9 mm, lanceolate, appressed purple villous, the margins entire, the apices acute; pedicel 0.8–2.5 cm long, ca. 1 mm wide, spreading villous. Calyx 5-parted nearly to the base, 0.8–1.2 × ca. 0.5 mm, lobes linear-lanceolate, appressed villous outside, glabrous inside, the margins entire, the apices acuminate. Corolla pale purple, 1.2–1.8 cm long, pubescent outside, sparsely pubescent inside, the tube 0.8–1.3 cm long, 4–6 mm in diameter at the mouth, ca. 2.4 mm in diameter at the base; limb distinctly 2- lipped, adaxial lip 2-lobed to over middle, the lobes 2–3 × ca. 3.5 mm, oblong, the abaxial lip 3-lobed to near middle, the lobes 3–4 × ca. 4 mm, oblong. Stamens 2, adnate to ca. 5 mm above the corolla base; filaments ca. 6 mm long, purple, sparsely pubescent, strongly geniculate at 3.5 mm above the filament base, anthers ca. 2 mm long, glabrous, barbate abaxially. Staminodes 3, lateral ones ca. 4 mm long, apices capitate, purple, glabrous, adnate to 5 mm above the corolla tube base, middle one 0.3–0.6 mm long, adnate to 5 mm above the corolla tube base. Disc ca. 0.9 mm in height, margin orbicular, glabrous. Pistil 1.0– 1.4 cm long, ovary 4–7 mm long, ca. 1 mm wide, mixed pubescent and glandular-pubescent; style 5–8 mm long, ca. 0.6 mm wide, mixed pubescent and glandular-pubescent; stigma cordiform, apex retuse, 0.5 mm wide, 2-lobed. Fruit a straight capsule, 1.3–2 cm long.

The other ecotype of the new species above is also shown in Fig. 2 D, I, K , which differs from the first one ( B – C, H, J in Fig. 2 ) by a leaf pubescence with long white or purple hairs.

Ecology, phenology and etymology: — Only two populations have been found for the new species, one at the peak of a limestone hill in Longgang National Nature Reserve and the other on the precipice of a limestone hill in Chunxiu Nature Reserve, both from Longzhou County, Guangxi, China . It flowers in September to November. The specific epithet is derived from the type locality, around the border of China and Vietnam .

Distinguishing characters: — Primulina sinovietnamica is morphologically close to P. pungentisepala ( Fig. 2 E, L ) and P. ningmingensis ( Fig. 2 F, M ), but it can be distinguished from the latter two by a few qualitative and quantitative characters in leaf, bract, calyx, staminodes and stigma, as shown by the detailed morphological comparisons of the three species in Table 2.

Additional specimens examined (paratype):— CHINA. Guangxi: Longzhou County, Chunxiu Nature Reserve , on the precipice of a limestone hill, 22°25ʹ22.02ʺ N, 106°38ʹ30.08ʺ E, 288 m, 19 October 2010, Yu- Song Huang Y0027 ( IBK!) .

Figures

FIGURE 1. Bayesian majority-rule consensus phylogram based on the sequences of the matK gene, with both posterior probabilities and MP bootstrap supports bigger than 50% mapped to the branches. The three accessions representing the new species are highlighted in bold.

FIGURE 2. Primulina sinovietnamica. A) habit; B) leaf; C) opened corolla; D) stamens; E) pistil and opened calyx; F) stigma. Drawn by Yun-Xi Zhu.