first it depends on what you want for an identification.
If you are looking for a specific specie or hybrid name that would have been on the tag, it is impossible without DNA and there is no DNA database. You can not identify anything that specific once the tag is lost.
Trying to ID from a flower is even harder. I have had two very different looking flowers come out of the same flower spike. Many orchids that bloom several time a year, an example is this Golden Tang that over the last three years consistently produces different color flowers depending on the time of year.
If you are looking for general family identification for culture reasons then you can easily identify the family of plants from the shape of the leaves.
Culture for most beginners is either Cattleya alliance, oncidium, alliance, dendrobium or phalaenopsis. Except for orchid nurseries these are 95% of all orchids you will find in garden shops of big stores. Fortunately the care of each of these groups is fairly consistent. By knowing the family you will know how to care for it.
For drawings of the leaf shapes and family identification go to the Canadian orchid congress web site where they have all the AOS cuture sheets organized in one place.
http://www.canadianorchidcongress.ca...e/culture.html
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