Commonly known as Greenhood orchids, for obvious reasons, the Pterostylis are terrestrial (growing in the ground) orchids from Autralasia. There are about 100 species and all have rather macabre, dull coloured, hooded flowers. I found this one (which I think is P. curta), easy to look after. Potted (or repotted since it increased fast) in late summer in gritty compost, it rapidly covered the soil surface with flat green leaves and then sent up a stem with a single flower about 4cm tall. It does not need great heat but it needs good light in winter when it is growing.