Brian Mathew, in Dwarf Bulbs, says 'O. nanum is very dwarf, up to 5cm when in flower, with many narrowly linear leaves in a basal tuft. Flowers about 1.5cm diameter, white with broad green stripe along each segment, produced in a dense head-like raceme. Wild in Italy and Balkans on grassy hillsides at low altitudes. Possibly only a variant of O. exscapum.'