Spiradiclis rosulata, a new species from limestone areas of Guangxi, China

Spiradiclis rosulata sp. nov. (Rubiaceae) is described from the Guangxi Zhuang Autonomous Region, China. It is morphologically similar to S. loana and S. tomentosa, but differs from the two species in having a densely villous indumentum on the adaxial side of the leaf, shorter calyx lobes, and a higher ratio of corolla lobe to tube. The new species is provisionally evaluated as ‘Vulnerable’ (VU) according to IUCN Red List Categories and Criteria.