Herbarium sheets may have attached packets or envelopes that contain loose specimen fragments or other material.
These fragment packets may contains loose leaves, leaflets, flowers, fruit, seeds, spores, scales, hairs, or samples of bark, etc. that may have separated from the original collection before mounting. Fragments that detach from the sheet during routine handling are also placed in packets.
When parts of the specimen are removed for dissection and study, the remaining fragments are placed in packets which are attached to the herbarium sheet.