Continuing a thread from below, a good internet site to do research is www.orchidspecies.com A lot of the requirements - temperature and light levels needed are included on this site. I am a big fan of Pleurothallids, especially Pleurothallis and some Masdevallias. Some are true miniatures, reaching inches in height. My only hesitation in recommending these is the limited air movement in most PDF tanks. I use a mesh screening located in the back section of my lid, allowing for evaporation. Watering in the evening can pose problems too. It is good that the leaves be dry in the evening, when or if it cools down. A few specie I would recommend are Pleurothallis grobyii, Pleuro. linearifolia, Masdevallia ampullacia and Masd. guttulata.
I was an orchid grower before a frog person and they're great! I hope the interest in orchids being used in PDF enclosures continues. Oh, also check out www.wildsky.com - the terrarium section.
Jon
