im not familiar with this as well but doing a search from google this is what i've found.
hope this helps.One of the tiniest orchids of the world -although its proportions are not the only feature that makes it attractive for cultivation :its flowers also assume unusual shapes . In the wild ,the species grows in the company of deciduous Dendrobium orchids and its development during the year also resembles that of deciduous Dendrobia. Its small , flat ,rounded pseudobulbs reach the size of 0.4 in /1 cm and, after the end of the vegetation period,shed all of their tiny lineated leaves . Flowers appear before the onset of the wet season . They grow individually on short spikes ,have a pronouncced lip and are light green with a russet marking . Grow them as you would deciduous Dendrobium orchids -provide them with a well- ventilated ,semi-shady environment with sufficient watering and fertilization in the summer,and a longish cool and dry dormancy in the winter.D.siamensis blooms between February and March and is known to grow in Burma ,Laos and Thailand.