Zeuxine strateumatica (L) Schiechter
The flower form is slightly contracted at the middle and abruptly dilated at the apex, not extending beyond the sepals. Flowers occur in the winter, November to March.
Given the weedy nature of these plants and their spontaneous appearance in a given location, it is likely autogamous (internal self-fertilization) or apomictic (mingling or nonsexual reproduction). Very abnormal, indeed.
The tiny orchid is native to Asia, known from China to the tip of India, including Southeast Asia and adjacent islands. It was originally described in 1753, taken from the Greek strateuma meaning a band, company, or army. In 1911 it was moved to the genus Zeuxine by Schlecter. The orchid is a 'here-now, gone-tomorrow' plant. It emerges in winter, blooms late in December or January and within a few weeks it vanishes. The following year it may or may not return.