The use of microwave ovens to treat herbarium specimens as part of the curatorial process, while efficient and convenient, may cause irreparable damage and loss of information for future researchers.Several articles have recently appeared concerning the use of small microwave ovens to kill insects infesting herbarium specimens (Hardin, 1981;Hall, 1981Hall, , 1982. The microwave radiation acts upon the water contained within the insect body, heating it to the boiling point and killing the insect. The method is relatively inexpensive and rapid, as well as effective.However, there are problems with this technique. As Hall (1982) has pointed out, metal clips, staples, or wire attached to specimen sheets can become hot enough to char paper or fiber structures that they contact. He has also pointed out that stems have been known to split open due to the presence of some water inside. Physical damage to specimens, then, can result.During my research on Malvastrum (Hill, 1982) I found that seeds obtained from herbarium specimens collected as long as 46 years ago could be germinated. The plants were grown, studied, and, again, vouchered. In several cases the seeds were of species that have been collected less than a half dozen times in the last 250 years (such as Malvastrum scoparioides E. Ulbrich). The danger that I foresee is to this valuable seed source. The treatment of seeds containing water with microwave radiation will destroy the ability of these seeds to germinate, eliminating the possibility for information retrieval or simply the possibility for the propagation of many rare or unusual species. Since only economically or horticulturally important species seem to have government or commercial 'seed banks,' the seeds of species oflesser general interest can be obtained only by often expensive travel, by special request from other botanists, or from herbarium specimens upon permission of the curators. Many genera, such as Malvastrum, may produce hundreds of seeds per plant, each with a resistant seed coat that will stand the low heat and chemical treatments of the standard preservation processes. The removal and subsequent germination of a few seeds from such a specimen can provide invaluable information about the living plant not possible after microwave treatment.Other propagules, such as spores, may likewise be affected by microwave treatment. One must carefully weigh the advantages and disadvantages of this curatorial method. If microwaves are still to be used on specimens with viable propagules, it would be very helpful to provide this information to researchers in the form of a stamp or label on the specimen.