Hoya phyllura is endemic to Borneo, and originally was a poorly known species from Kalimantan with yellow flowers. When an orange flowered form was found in Sabah’s Crocker Range it was thought to be a different species and was named Hoya linusii. However when other color forms were later found it was determined that Hoya linuii is a synonym of Hoya phyllura.
The above information was summarized from the book A Guide To The Hoyas of Borneo. Below the buds on my Hoya phyllura: