There is something about a plant that one has collected oneself that cannot be duplicated by a specimen made available in laboratory. You will also learn the advantage of making good specimens and field notes. Suffice it to say that you can save yourself hours of work by doing so. Bear in mind that any good plant specimen kills at least part of a plant. Make sure you have a reason for making the specimen and do so in an appropriate manner.
Voucher specimens .
A voucher specimen is one that documents what you found or worked with in a study. . Voucher specimens can be examined long after a study has been completed. They enable others to check your identifications and, if there are taxonomic changes affecting the species that you worked with, make it possible for subsequent workers to determine what your plants would be called according to the more recent taxonomic treatment. An ecological or environmental study that is not documented by specimens is of questionable validity. No one can prove that it is flawed because of misidentifications, but nor can it be proved that your identifications were correct.