Impatiens chinensis

It was a painfully slow 24 hrs ride from Hoi An to Dalat. I left Hoi An in the evening to arrive in Nha Trang around dawn. I caught the bus to Dalat at round 9 am traveling at 50 km/hr through rather degraded pastureland. The bus snaked up to the Dalat plateau after lunch. The montane coolness was revitalizing and refreshing; pine plantation started to appear. From the window, i caught a glimpse of delicate pink flowers near ditches or drainage channels. Unfortunately, the bus was not going to stop... However, i was lucky my guide brought me to a less frequent small waterfall the following day to see the dalat sights. Here i managed to photograph this beautiful Impatiens chinensis in situ. It was then approaching the dry season, there were no mature seed pods to be seen.

Trying to pin a name to this species drawed a blank until 2006 when a Taiwanese nurserymen identified it as I. chinensis. It was said to be common weed of Southern China in marshy areas. A websearch yields couple of photos of this species but the flowers are smaller, less symmetrical and the color is inferior. If you can confirm; or suggest another identification, would like to have your comments.