I have saved these photos in the Post site but has not properly located the names of the first 2 photos. Surely they are all from Family Rubiaceae. However, the first two photos' scientific names elude me until now. They grow like a bush or small tree and terribly beautiful in full sun. Butterflies and insects love them too.
(P.S. Thanks to Stephanie of Steph's Garden for the ID of the first 2 photos: Carphalea kirondron)
Photos 3, 4 and 5 are Ixora javanica. They also perform well even in partially shaded areas. They grow tall if not pruned. Reports show they have anti tumor properties.
Photo No. 6 is the Ixora coccinea, the dwarf counterpart. It has many hybrids and colors. Most Rubiaceae plants taste splendid for butterflies. I think maybe they love them because they don't need to go far for the nectar. They just transfer their proboscis from one flower to another within an umbel, and not waste lots of energy in flying. For photographers, it is easier to shoot them while in these flowers.