Underside (above) and upperside (below). Opposite or alternate? These descriptions don't work for the peculiar leaf-arrangement of Sagarethia. Though the leaves are in roughly opposite pairs, each pair reverses the positions of the preceding pair, in other words it goes left-right - right-left - left-right etc.....
Sagarethia is known in the west only to bonsai fans. Whether its curious leaf arrangement once conferred a benefit to some ancestor in the battle for survival, I don't know. In today's plant it seems to be a mildly embarrassing genetic legacy whose impact has been ingeniously minimized, leaving only a beauty of character. But this may be a misconception.