|
 |
|
HOW TO PREPARE A PLANT SPECIMEN AS A HERBARIUM VOUCHER Why do it? A pressed, dried plant specimen added to a herbarium collection provides a "voucher" for sight records and other observations about the spread of an exotic pest plant in Florida. It allows many more researchers to confirm or update the identity of the recorded plant and offers long-term evidence viewable by future researchers of the distribution of a plant species over time and regions. Collecting the specimen The first rule is to NOT collect a whole plant, roots and all, if you see fewer than a dozen individuals of the species in the immediate vicinity. Take several pictures, including close-ups, or collect only a flowering portion of one plant, if you are not sure the plant is exotic and you see only a few individuals. This collecting habit is meant to safeguard against accidental collection of uncommon native plants.Also remember that any collecting requires an official permit on public lands or waters and the landowner's permission on private lands. (Unauthorized collecting is punishable under criminal law.) For herbaceous species, collect a whole plant, with roots, a piece of rhizome if present, main stem, leaves, and reproductive parts (flowers and/or fruits, sporangia, cones, etc.). Knock off dirt clumps and pat off dripping water from plant parts. For woody species, collect a portion of vine or twig with leaves and reproductive parts (flowers, fruits, or cones). In some cases, a piece of trunk bark aids in identification of the specimen. For exotic bamboo species, collect a portion of stem that shows its typical internode coloration and that includes at least one node to show the typical branching pattern. Note any marked difference in internode color near the stem base vs. midstem and color differences, if any, of stems in shade vs. full-sun. Also collect a set of branchlets with leaves. You are unlikely to see flowering parts, but if so, certainly collect one inflorescence as well. For exotic palms, collect a frond (cutting into sections if necessary) and a portion of inflorescence. Note the presence of fibers or special structures at the leaf bases. If dozens of plants of the target species are present, collect two, three, or four specimens of the species to allow distribution of duplicates to other herbaria. Take notes on the collection date, location, habitat, plant height, growth habit, etc. (see section below on label data). Pressing the specimen Place the specimen or specimen parts flat within the fold of a newspaper page. A sheet from a "tabloid"-sized section of your daily newspaper works nicely. Make a note on the outer edge of the paper that will help you connect the specimen to your field notes for that collection. Open the newspaper sheet. Then spread, fold, or bend the specimen as necessary so that it takes up no more than an 11" x 16" space, and fold the top half of the sheet back over the specimen. For wet, delicate, or juicy specimens, you can place them within a fold of wax paper placed within the newspaper fold. For large or bulky specimens, cut sections to fit the space, choosing pieces that help identify the species. If you’re not sure how to handle a particular specimen, contact your regional herbarium (see list below). The staff will be glad to advise you. Place the folded newspaper sheet with specimen between two sheets of blotter paper (or something similar like poster paper, for absorption of moisture), and then that sandwich between two pieces of cardboard (for aeration). For bulky specimens, you can add pieces of cushioning material (such as spongy carpet padding) between the blotter paper and newsprint. Then add evenly applied pressure to the stack. The typical plant press includes a several-layered stack, two outer wooden covers, and straps that can be pulled tightly to apply pressure. The technique is intended to flatten the specimens as they dry. If you have no press and only one or two specimens, you may be able to use heavy books or similar weight to gain the same effect. Drying the specimen The basic ingredients for drying a pressed plant are warmth, dry air, and a bug-free location. "Warm" is easy in Florida, "dry" and "bug-free" not so easy. If you don’t have access to a herbarium drying cabinet, think about a spot that might work. A specimen can be air-dried in an air-conditioned room, but it will usually take longer, and you will have to watch for mold and bugs. A few days in the trunk of a vehicle that travels in the Florida sun often works, with some vigilance for bugs, dampness, and not-TOO-hot temperature. Depending on the plant species and drying conditions, a pressed specimen may take 24 hours or as much as two weeks to dry. Writing up the specimen label The collection data provided on the label that accompanies the specimen is as important as the specimen itself. Use acid-free bond paper to type up the label, which should include the following: Scientific name of plant -- genus, species (+ subspecies, variety, or cultivar name if needed), and taxonomic authority (available in botanical references such as Wunderlin, R. P. 1998. Guide to the Vascular Plants of Florida. University Press of Florida. Gainesville).Location -- Florida county where found, plus name of park, preserve, city, or community, and details on location such as distance to nearest road or highway junction. (Think about how you would give directions to the site.) An additional reference to the section-township-range or to latitude/longitude readings for the site is most helpful. Habitat -- what kind of plant community the plant was found in (sandhill, flatwoods, coastal hammock, river swamp, etc.). You can also mention a few of its common associates (other plant species) at the site, by scientific name, if known. Frequency of occurrence -- whether the plant was rare, occasional, frequent, common, or in a dense monoculture at the site. (Were there only a few scattered plants, many scattered ones, thick patches, dense stands, etc.?) Habit -- form of the plant (tree, shrub, vine, herb); the plant’s growth habit (creeping, sprawling, clambering, erect, bushy, columnar, clump-forming, running, submersed, emersed, etc.). Estimate and note the height of a tree or shrub. Note the water depth if found in standing water. If a character of the plant might be lost in the drying process, such as the petal color, note what it is when fresh in the field. Collector -- Include your name, and your personal collection number for the specimen, if you have one (if you don’t, just put the Latin abbreviation s.n., which means "no number"!). Include the name(s) of other people with you at the site, as "Collected with: ______." If someone secured the identity of the species for you, add the person’s name as "Determined by _______." Date of collection -- Don’t forget this important item. Having examples of a plant’s growth form at a particular time of year can be extremely helpful in managing it. The date is also essential to tracking a plant’s occurrence over time. EXAMPLE LABELS
Depositing the specimen Once you have the specimen pressed and dried, and the label written up, you should send it to a local or regional herbarium for storage and future accessibility. Herbaria are botanical laboratories designed for safe, long-term storage and use of preserved plant specimens. For mailing, pack specimens carefully, with a stiff cardboard sandwich for each one and with placement in wrapping and/or a box such that the specimen(s) can’t slide around or break. If you have duplicates for other herbaria, you might ask your local or regional herbarium to forward those. Addresses for regional herbaria in Florida include the following. At their web sites, you’ll find additional information about plant occurrences in Florida and the work of herbaria. Herbarium, Fairchild Tropical Garden, 11935 Old Cutler Rd., Miami, FL 33156; phone: (305) 665-2844. http://www.virtualherbarium.org/Godfrey Herbarium, Department of Biological Science, Florida State University, Tallahassee, FL 32306; phone: (850) 644-6278. http://www.herbarium.bio.fsu.edu/Herbarium, Florida Museum of Natural History, University of Florida, P.O. Box 110575, Gainesville, FL 32611; phone: (352) 392-1767. http://www.flmnh.ufl.edu/natsci/herbarium/Herbarium, Institute for Systematic Botany, Biology Department, University of South Florida, Tampa, FL 33620; phone: (813) 974-2359. http://www.plantatlas.usf.edu/isb/herbarium.htm
Web page updated by K. Craddock Burks, 9/6/05. |
|
Webmaster tony_pernas@nps.gov |