Hoya spectatissima is a recently described species of Hoya from China, celebrated for its beautiful flowers, which are reflected in its name "spectatissima," meaning "most spectacular" or "most showy."
 
Origin and Discovery
Hoya spectatissima is native to Yunnan Province, China. It grows as a lithophytic liana, meaning it's a woody vine that climbs on rocks, particularly in karst habitats (limestone formations). It is known from at least two localities in Cangyuan Hsien and Gengma Hsien, Yunnan Province.
The species was recently discovered and formally described in 2023 by a team of Chinese botanists: B. Xue, E.F. Huang, Gang Yao, G. Zhao, and J.X. Huang. The holotype (the primary specimen used for description) was collected on July 7, 2021, by E.F. Huang in Guanlong Village, Gengma Hsien.
The original publication details are:
Xue, B., Huang, E. F., Yao, G., Zhao, G., & Huang, J. X. (2023). Hoya spectatissima (Gentianales, Apocynaceae), a new species from Yunnan, China. PhytoKeys, Vol. 222, pp. 69-74.
You can find this publication online, for example, on the PhytoKeys website: https://phytokeys.pensoft.net/article/99420/ or through the International Plant Names Index (IPNI): https://www.ipni.org/n/77316067-1.
 
Key Characteristics
Leaves: Hoya spectatissima has succulent leaves that are elliptic or oblong, typically measuring 2–4.5 cm in length and 1.3–1.8 cm in width, and about 2.5–3 mm thick. When young, the leaves can be wine-red and pubescent (hairy), maturing to bright green on the upper side and pale green on the underside. The apex of the leaves is rounded or rarely obtuse. The mid-vein is slightly elevated or obscure on the upper side.
Growth Habit: It is a lithophytic climber with stems that can reach up to 1 meter in length. The stems are rounded in cross-section and are densely pubescent when young, becoming subglabrous (nearly hairless) when mature. It can form branches at the nodes.
Flowers: The flowers are truly "spectacular." They are borne in many-flowered, globose (spherical) pseudo-umbels. The corolla is rotate (star-shaped), about 2 cm in diameter, and changes color from pink in the early flowering phase to pale pink in the later phase. The corolla lobes are densely sericeous (silky-hairy) on the inside and sub-glabrous on the outside. The corona (center) is ivory white, with sub-rhombic lobes that have an acute outer angle and acuminate inner angle. The inner tips are convex and spread towards the center of the flower. The flowers are likely fragrant, though the specific scent is not detailed in the initial description.
Blooming: The plant forms axillary inflorescences (from leaf axils).
 
Care Requirements for Indoor Cultivation (Based on its native habitat and general Hoya care)
Given its relatively recent description, specific long-term cultivation details are still emerging, but general Hoya care principles, adapted for its succulent leaves and lithophytic nature, apply. It is noted to be a "cooler grower" by some experienced hobbyists.
Light: Prefers bright, diffused light. As a lithophyte climbing on rocks, it likely receives ample light but may be protected from the most intense, direct sun. A few hours of gentle morning sun could be beneficial, potentially enhancing the reddish hues of young leaves.
Watering: With succulent leaves, it suggests a need for well-draining conditions and tolerance for periods of dryness. Allow the potting mix to dry out significantly between waterings, but don't let it remain bone-dry for extended periods. When watering, drench thoroughly and ensure excess water drains away.
Humidity: As a plant from a humid, subtropical biome, it will appreciate moderate to high humidity, ideally above 50%. Regular misting can be beneficial, especially in dry indoor environments.
Temperature: Described as a "cooler grower," it likely prefers intermediate temperatures, possibly slightly cooler than many lowland tropical Hoyas, perhaps in the range of 18−25∘C . It should be protected from cold temperatures below 5∘C 
Soil/Substrate: As a lithophyte, it needs an extremely well-draining and airy substrate that mimics its rocky habitat..
Potting: Prefers to be somewhat root-bound. Choose a pot with excellent drainage.