Dendrobium, but what family?

[rosie]

Could anyone tell me the name of this Dendrobium. The flowers, are dainty, 1inch.across, pale lilac with purple tips on edge of petal. Small purple dots on lip, with a yellow tinge inside throat. Flowers approx. twice a year. Very hardy. Sometimes 2 stems of flowers come from the top of one cane. Very much appreciate any help.