Spiradiclis yanii Y. Nong & L. Wu, 2024

Nong, You, Lei, Li-Qun, Wei, Gui-Yuan, Qu, Xin-Cheng, Zhao, Zi-Yi, Feng, Bin, Xu, Chuan-Gui & Wu, Lei, 2024, Spiradiclis yanii (Rubiaceae), a new species from Guangxi, China, PhytoKeys 247, pp. 173-181 : 173-181

Spiradiclis yanii Y. Nong & L. Wu sp. nov.

Figs 1 , 2 , 3 , 4 Chinese name: yán shì luó xù cǎo (严氏螺序草 )

Diagnosis.

Spiradiclis yanii is most similar to S. tomentosa , but is different in being densely villous without knots (vs. densely grey-viscid multicellular tomentose); leaves narrow elliptic or oblanceolate (vs. oblanceolate, obovate or rarely elliptic); apex acute or shortly acuminate (vs. apex cuspidate to rounded); mid-vein flat adaxially and convex abaxially (vs. mid-rib and lateral veins nearly flat on both sides); stipules 2–4, linear or linear lanceolate, 4–8 mm, densely villous (vs. stipules persistent, triangular, 8–22 mm, tomentose); corolla tube 3 mm, sparsely pubescent inside (vs. tube 6–8 mm, glabrous inside); lobes 3–5 (vs. lobes 5); stamens arising at the base of the tube (vs. located at the throat of the corolla); stigma 2 - lobed, lobes ovoid, slightly swollen, 0.2 mm (vs. stigma deeply bifid with linear lobes, 1–1.5 mm). At first glance, it also looks similar to S. villosa X. X. Chen & W. L. Sha , but differs by its leaves narrow elliptic or oblanceolate, 5–10 × 2–2.5 cm, densely villous adaxially and abaxially (vs. leaves oblong-elliptic or obovate-elliptic, 10–25 × 3–8 cm, adaxially dark brown pubescent, abaxially densely brown villous), petiole 0.5–1 cm (vs. petiole 3.5–7 cm), stipules 2–4, linear or linear lanceolate, 4–8 mm, densely villous (vs. stipules 2 - lobed, densely dark brown villous, lobes laciniate, 15–30 mm). More detailed morphological differences amongst the three species are shown in Table 1 .

Holotype.

China • Guangxi: Longan , 23 ° 03 ' 03 " N, 107 ° 22 ' 20 " E, alt. 327 m, on the cliff at the bottom of a sinkhole, 7 March 2024, Y Nong NY 2024030701 ( GXMI) (holotype: GXMI!; isotypes: IBK!).

Description.

Perennial herbs, erect, 5–25 cm tall, stems cylindrical, 1–2 branches, densely multicellular villous when young, but grabrous when old; Leaves opposite, leaf blade drying membranous, narrow elliptic or oblanceolate, 5–10 × 2–2.5 cm, densely multicellular villous adaxially and abaxially, base cuneate or acute, apex acuminate or shortly acuminate, petiole 0.5–1 cm, densely villous; Mid-vein flat adaxially and convex abaxially, secondary veins 9–14 pairs; Stipules 2–4, linear or linear lanceolate, 4–8 mm, densely villous. Inflorescence terminal, paniculiform, peduncles 6–15 cm, densely villous, pedicels 3–6 mm, bracts linear, 3–7 mm; Hypanthium portion turbinate, 4 mm, calyx lobes 5, linear or narrow lanceolate, 1.5–2 mm; Flower homomorphism, corolla white, lobes 3–5, ovate, 2–3 mm, outside sparsely pubescent, glabrous inside, tube 3 mm, sparsely pubescent inside; Stamens 5, arising at the base of the tube, not protruding, glabrous, filaments 2 mm, anthers oblong, 0.5 mm; top of the ovary 4 - lobed, sparsely pubescent; Ovary 2 - loculed, with many ovules, style 2–3 mm, glabrous, stigma 2 - lobed, lobes ovoid, slightly swollen, 0.2 mm; Capsule obovate, ca. 1 mm in diam., valves 4, persistent calyx lobes 2–4 mm; Seeds numerous, small and angular.

Phenology.

Flowering and fruiting in February to March.

Etymology.

The new species is named after Mr. Ke-Jian Yan, who worked in Guangxi Institute of Chinese Medicine & Pharmaceutical Science and made many contributions to GXMI, especially in Rubiaceae and Lamiaceae .

Distribution and habit.

Known only from the southeast of Guangxi, China. It has been mainly found on cliffs at the bottom of a sinkhole at elevations of 320 m.

IUCN red list category.

Data available for the new species are still insufficient to assess its conservation status. According to the IUCN Criteria ( IUCN 2022), it is considered Data Deficient ( DD) until more information becomes available. Although S. yanii currently has relatively good growth, further collection and monitoring are necessary to allow more conclusive estimations about the rarity and vulnerability of the species. Therefore, special attention should be given to the conservation of the new species of Spiradiclis .

Additional specimen.

Longan • Southeast Guangxi: limestone hills, 7 November 2011, J. C. Yang & Y. B. Liao TK 028 ( IBK!) ; Longan , 14 March 2024 Y Nong NY 2024031401 ( GXMI!) .

Figures

Figure 1. Habitat of Spiradiclis yanii Y. Nong & L. Wu on cliffs at the bottom of the sinkhole. Photographed by YN.

Figure 2. Line drawing of Spiradiclis yanii Y. Nong & L. Wu A flowering branch B flower C ovary and stigma D filaments of stamens and perianth E capsule F seeds G stipules (Drawn by Xin-cheng Qu).

Figure 3. Spiradiclis yanii Y. Nong & L. Wu A, B plant (flowering and fruiting) C inflorescence (lateral view) D inflorescence (front view, corolla lobes 3–5) E flower (front view) F stamens, ovary and stigma G infructescence (lateral view) H calyx and bracts I capsule J seeds K leaf (adaxially view) L leaf (abaxially view) M, N stipules (Photographed by Ke-Jian Yan & You Nong, edited by You Nong).

Figure 4. Digital images of type specimens A Spiradiclis yanii B S. tomentosa C S. villosa.