Type specimen of Tainia hongkongensis was collected in Hong Kong and it is quite narrowly distributed geographically. T. hongkongensis is the commonest species among the three Tainia in Hong Kong. The other two are T. ruybarrettoi and T. dunnii. It is not difficult to seperate them where the lip of T. ruybarrettoi is distinctly three-lobed while that of T. hongkongensis is entire or subentire. No photo of T. ruybarrettoi at the moment and I'll try to come back to this after finding it. Pseudobulb of T. dunnii is thin and cylindrical but that of T. hongkongensis is swollen and ovoid (or nearly globose). The difference of them should be distinctive.
T. hongkongensis is one of the commonest orchids in Hong Kong which can mainly be found under forests or forest edge. It is used to flower in April in Hong Kong but started few weeks earlier this year, probably deceited by the last humid and warmer winter.
Close-up of the lip of T. hongkongensis.
Key to genus Tainia in Flora of China:
Illustration of T. ruybarrettoi: