Hoya flagellata comes from Thailand and the flowers are so similar to Hoya caudata that many collectors think that it may just be another clone of caudata.  H. flagellata was described in 1940.  The leaves are long and narrow and get almost totally red in good light.  The flowers are around .5″ across (1.2 cm) and are covered with hairs.  The corona is red with long “hairs sticking out of the center.  Here is  a photo the first morning after the flowers just opened: