Ke-Jian Yan spiradiclis (Spiradiclis yanii) is not Ophiorrhiza, new species from Guangxi, China

NEWS - Ke-Jian Yan spiradiclis (Spiradiclis yanii), Rubiaceae, a new species known only from southeastern Guangxi, China, and mostly found on cliffs at the bottom of sinkholes at 320 m elevation with a flowering and fruiting season in February to March.

Spiradiclis Blume is most similar to Ophiorrhiza L. and both genera are within Ophiorrhizeae. More recent studies suggest that the situation may be more complex and raise questions about the separation of these genera.

However, Spiradiclis differs morphologically from Ophiorrhiza in that the capsule is oblong-linear or subglobose with four valves (vs. obchordate and compressed capsule with two valves) at maturity. Since the delimitation and relationships of the two genera still require further study, this study prefers to accept the traditional concept of Spiradiclis.

During a field survey in Longan, Guangxi, in March 2024, researchers found a special Spiradiclis population in flowers and fruits that was morphologically similar to S. tomentosa D. Fang & D. H. Qin. However, this special population was clearly different from S. tomentosa.

This special population might represent a new species after further observations and checking many Spiradiclis specimens from Herbaria and consulting relevant literature. Finally, the researchers conducted one more field survey to confirm the unusual plant was a new Spiradiclis to science.

S. yanii is most similar to S. tomentosa, but differs in that the villi are dense without nodes (vs. densely thick gray multicellular tomentose), narrow elliptic or lanceolate leaves (vs. lanceolate, obovate or rarely elliptic), acuminate or slightly acuminate apex (vs. acupoint canine to rounded), flat midvein adaxial and convex abaxial (vs. midvein and lateral veins almost flat on both sides).

Stipules 2-4, linear or linear-lanceolate, 4-8 mm, densely villous (vs. persistent stipules, triangular, 8-22 mm, tomentose), corolla tube 3 mm, sparsely pubescent inside (vs. 6-8 mm, glabrous inside), lobes 3-5 (vs. 5), stamens present at base of tube (vs. located in corolla throat), pistil 2-lobed, lobes ovate, slightly swollen, 0.2 mm (vs. deeply branched pistil with linear lobes, 1-1.5 mm).

At first glance, it is also similar to S. villosa X. X. Chen & W. L. Sha, but differs in narrow elliptical or lanceolate leaf shape, 5-10 × 2-2.5 cm, dense villi on adaxial and abaxial sides (vs. oblong-elliptical or oblong-elliptical leaves, 10-25 × 3-8 cm, dark brown pubescent on adaxial side, dense brown villi on abaxial side), petiole 0.5-1 cm (vs. 3.5-7 cm), stipules 2-4, linear or linear-lanceolate, 4-8 mm, dense villi (vs. stipules 2 lobes, dense dark brown villi, lobes laciniate, 15-30 mm).

The new species was named after Mr. Ke-Jian Yan who worked at Guangxi Institute of Chinese Medicine & Pharmaceutical Science and made many contributions especially in the field of Rubiaceae and Lamiaceae.

Although the new species is currently growing well, further collection and monitoring are needed for a more confident estimate of the species' rarity and vulnerability. The available data are still insufficient to assess its conservation status. According to the IUCN Criteria (IUCN 2022), the species is considered Data Deficient (DD) until further information is available.

Original research

Nong Y, Lei L-Q, Wei G-Y, Qu X-C, Zhao Z-Y, Feng B, Xu C-G, Wu L (2024). Spiradiclis yanii (Rubiaceae), a new species from Guangxi, China. PhytoKeys 247: 173-181, DOI:10.3897/phytokeys.247.123867

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