Primulina clausa P.W.Li & M.Kang, 2021

Li, Peng-Wei, Pan, Bo, Harris, Aj, Xu, Wei-Bin, Liu, Ming-Tao & Kang, Ming, 2021, Primulina clausa, a new species of Gesneriaceae from northern Guangxi, China, Phytotaxa 510 (2), pp. 187-192 : 188-190

Primulina clausa P.W.Li & M.Kang , sp. nov. ( Fig. 1 , A–J)

Diagnosis: — Primulina clausa is morphologically similar to P. obtusidentata ( Wang 1981a: 57) Mich.Möller & A.Weber in Weber et al. (2011: 784), but can be readily distinguished from the latter by its slightly unfolded bracts (vs widely spreading or reflexed), appressed sepals (vs spreading), glabrous anthers (vs villous), parietal placenta (vs axile placenta with sterile lower locule), and nearly straight capsule (vs falcate).

Type:— CHINA. Guangxi Zhuang Autonomous Region: Xing’an County, Xing’an Township , 217 m, 25°34.41′ N, 111°37.24′ E, 28 June 2016, P. W . Li LPW2016063 (Holotype PE!; isotypes PE!, IBSC!) .

Description:— Perennial herbs, acaulescent. Rhizome inconspicuous. Leaves basal; petiole 2.3–10 cm; leaf blade narrowly ovate to elliptic, 4–14× 1.5–8 cm, membranous or papery when dry, both sides pubescent, rarely mixed with capitate-glandular hairs, leaf base cordate to cuneate or oblique, margin entire to crenate, apex acuminate; lateral veins 4–6 on each side of midrib. Cymes 1–7, 1–6 flowers per inflorescence; peduncle short, prostrate, subequal to petiole, 3.5–7 cm, densely villous. Bracts 2, slightly unfolded, narrowly ovate to elliptic, 1.2–2.5× 0.7–1.8 cm, both sides sparsely pubescent, margin entire or inconspicuously serrate; bracteoles 2, linear. Pedicels short, 5–8 mm, glandular- and eglandular-hairy. Sepals broadly spatulate or oblong, 6–7× 3–4 mm, pubescent on both sides, margin ciliate, apex obtuse or truncate. Corolla funnelform, ventrally plicated, corrugations yellow with scattered orange spots and short glandular hairs; tube 2.9–3.5 cm long, white or pale pink, slightly gibbous near the orifice, glandular-hairy outside; limb blue-purple, upper lip 9–11 mm long, divided nearly to base, lobes broadly ovate, lower lip 13–16 mm long, 3- lobed, free to middle, lobes obovate-oblong. Stamens 2, inserted at the middle of corolla tube, filaments white, slightly coiled near the base, short glandular-hairy, anthers coherent, glabrous; Staminodes 3, filiform, two lateral ones inserted below the middle of corolla, the dorsal one adnate above corolla base. Pistil 3.5–3.7 cm, pubescent and glandularpubescent; ovary linear, 1.5–1.7 cm long; stigma linear-oblong, c. 4× 1 mm, slightly bilobed. Disc annular, 6–9 mm high, inconspicuously oblique, glabrous. Capsule nearly straight, 1.7–2.5 cm long. Seeds unknown.

Additional specimens examined (paratypes):— CHINA. Guangxi Zhuang Autonomous Region: Xing’an County, Xing’an Township , 22 June 2011, W . B . Xu & B . Pan 11165 ( IBK!); ibidem, 30 July 2013, P . W . Li LPW2013053 ( PE!); ibidem, 13 June 2016, L . H . Yang & B . Pan YLH351 ( IBSC!); Huanjiang County, Mulun National Nature Reserve , 1 June 2012, W . B . Xu & Y . S . Huang 11701 ( IBK!); Guanyang County, Xinxu Township , 10 August 2015, Guanyang Expedition 450327150810001 LY ( IBK!) .

Phenology:— Flowering from June to August and fruiting from July to September.

Distribution and habitat:— Primulina clausa is currently known from Huanjiang, Xing’an and Guanyang in northern Guangxi Zhuang Autonomous Region ( Fig. 2 ). It usually grows in damp karst caves or on shaded rocks under the forest canopy.

Etymology:— The epithet “ clausa ” refers to the subtending bracts which fold the flowers or capsules. The Chinese name for this new species is “bì bāo bào chūn jù tái mü报Þnö”.

Similar species:— Primulina clausa is morphologically similar to P. obtusidentata in having narrowly elliptic leaves, large ovate bracts, glandular filaments, subequal ovary and style, and an oblong stigma with the apex slightly bifid. However, they differ in many aspects. Primulina clausa has short and prostrate peduncles, slightly unfolded bracts, short petioles, appressed sepals, glabrous anthers and nearly straight capsules, while P. obtusidentata possesses vertical peduncles, spreading or reflexed bracts, long petioles, spreading sepals, villous anthers and falcate capsules ( Fig. 1 ). In addition, P. clausa is distributed in northern Guangxi, while P. obtusidentata is found in northeastern Guizhou and northern Hunan ( Fig. 2 ).

Figures

FIGURE 1. Photographs of Primulina clausa (A–J) with comparison of P. obtusidentata (K–P). (A) Habitat; (B, K) flowering plant, showing prostrate and vertical peduncles, respectively; (C, L) inflorescence, showing slightly unfolded and spreading bracts, respectively; (D) bracts; (E) side view of corollas; (F, M) front view of corolla, showing similar stigma shape; (G) longitudinal dissection of corolla; (H, N) capsule, showing nearly straight capsule with short pedicel and falcate capsule with long pedicel, respectively; (I, O) stamen, showing glabrous and villous anthers, respectively; (J, P) transverse section of middle part of ovary, showing parietal and axile placenta, respectively. Scale bars: B, 5 cm; C–E, L, N, 2 cm; F–H, M, 1 cm; I, O, 1 mm; J, P, 0.5 mm; K, 10 cm. Note: The scanning electron microscopy illustrations (I–J, O–P) were acquired following Dong et al. (2018).

FIGURE 2. The known geographical distribution of Primulina clausa and P. obtusidentata. The light blue shadow indicates main areas of karst based on GIS datasets from https://www.fos.auckland.ac.nz/our_research/karst/#karst5.