University of Alberta, Department of Biological Sciences Herbaria Herbarium Handbook

Transcription

1 University of Alberta, Department of Biological Sciences Herbaria Herbarium Handbook Plant Collection Plants may be collected for many different purposes. The purpose or end product often dictates the technique to be used. These instructions are for collection, drying and mounting terrestrial and aquatic vascular plants that will make good herbarium specimens because they contain a maximum of information about each plant. These instructions are also applicable to voucher collections (permanent collections to verify the data in a publication or study) for the purpose of identification of the plant since as much information as possible is required for an accurate determination. For the beginning plant identifier or amateur, a flowering or fruiting stem is often sufficient to permit identification. The digging up of whole plants is to be avoided unless justified for research purposes. Equipment Field Backpack: Notebook or pad of paper for recording data in field Trowel, heavy knife or other digging tool Pocket knife, pruning shears (for tough or woody plants) Plastic bags, paper bags or field press (light-weight and portable) Flimsies: Folded plain newsprint or sheets of (tabloid sized) newspaper about 56 x 40cm folded to 28 x 40cm or smaller GPS or Topographic maps compass first aid kit (including insect repellant and sunscreen) LUNCH and WATER Pressing and Mounting: Plant press and source of heat or moving air to hasten drying Mounting sheets or packets and labels Glue (Elmers or Weldbond), or permanent adhesive cloth tape (acid free) sponge forceps Identification: Field Guides or Floras applicable to the region Species lists for the area, if available dissecting microscope or 15X hand lens dissecting tools: probe, 2 forceps, ruler Collection of Vascular Plants Collection Ethics For general identification or for research purposes, there are conservation guidelines to follow when collecting native plants. First, find out about the laws that protect plants in a given area. Know which plant taxa are locally or nationally rare or protected. Avoid collecting these taxa if at all possible; if needed for research purposes, follow all necessary legal procedures for collecting. Always gain the owners permission before collecting on private lands.

2 Never collect plants in National, Provincial, or Municipal Parks or protected natural areas without a permit. Before picking any plant, survey the entire area noting the size of the population. Never pick the only plant or even one plant of a small population. A good rule of thumb is: pick only 1% or less of any given population. Never collect the last survivor of a population or species! If possible, use photographs to document the plants and keep in mind that others will visit the same site in the future. The Alberta Native Plant Council offers more detailed guidelines for collection at their web site: Selecting the Specimen(s) The classification of the flowering plants is based on the characteristics of the complete plant - roots, stems, leaves, inflorescence, flowers and fruits. Using a natural key such as Moss s Flora of Alberta requires that you be able to count flower parts. It is, therefore, a good idea to collect and press extra flowers and fruit for dissection. It is frequently impossible to identify an incomplete specimen. Collectors should, as a regular practice, secure at least one complete plant (underground parts and above ground parts in reproductive condition - with flowers and/or fruits, or sporulating) per sheet unless the plant is too large. If this is impossible, as in the case of trees, shrubs and large herbs, critical pieces may be taken and the characteristics of the whole plant (height, branching pattern, bark and twig colour, etc.) noted in a field notebook. Complete plants, if small, may be supplemented by additional material: either more entire plants showing the morphological variation within the population or critical fragments, such as flowers and fruits, to make a full sheet. Extra flowers, fruits, or leaves should be collected for deposit in a packet mounted on each herbarium sheet. Specimens should be selected to represent the population, or the departures noted. Aberrant individuals should not be picked out of a population and made into specimens unless there is a specific reason for doing so. Do not deliberately select either the largest or the smallest plants or pick the white-flowered individuals out of a predominantly blue-flowered population without noting this selection. Avoid the common fault of picking the smallest individual from a group of large plants merely because it will fit nicely on a sheet of herbarium paper. Collecting the Specimen(s) If at all possible, do not collect in wet weather or heavy dew. Trees, shrubs or large herbs - cut 2-3 dm lengths from ends of stem or branch, including, where feasible the flowers and/or fruit, a range in leaf sizes or types if these vary, and a small chip of bark from trees. Note whether twigs came from the same shrub or from different individuals, the colour and texture of the bark of old and young stems. Herbs or small shrubs - if too large to fit a sheet even when folded, cut apart and keep the inflorescence and upper leaves, a portion of stem with middle leaves, a portion with lower leaves and a portion of the main underground structures (label each section). Note the actual height of the plant. Medium to small herbs and shrubs - loosen soil around roots with trowel. Remove soil from underground structures by shaking, scraping or washing in water. Thick tuberous parts or large root crowns can be split with the pruning shears or knife. Be sure to collect critical material. Many groups, including Cruciferae, Chenopodiaceae, Gramineae and Cyperaceae, require well-formed mature fruit for precise identification. Others such as Violaceae, Orchidaceae, must have flowers at anthesis (at maximum bloom when pollen is released). Some flower colours fade or change with drying - be sure to note the flower colour

3 at the time of collection. The annual, biennial or perennial habit is diagnostic in many groups such as the Gramineae and Compositae, and a portion of the underground structures is required for determining this character. A portion of stem to show the type of leaf arrangement and character of the winter buds is critical for some shrub and tree species. Collect extra flowers and fruits for dissection which may later be necessary. The plants may either be collected directly between newspapers in the press (or an abbreviated field press) so they wilt in place or into a plastic bag in which they may be kept fresh for up to a few hours with moistened paper towels. They should be kept cool (in a cooler or refrigerator) and pressed as soon as possible (i.e. within a matter of hours) to prevent discoloring and decomposition. As plants are placed in the press, be sure to indicate on each newspaper holding specimens, the collection number and/or location. At the time of collecting, investigators should record the date, geographic location, habitat descriptions, and special features of the plant (height, flower colour, etc.) in a field notebook (see Data to be Recorded, below). Aquatic plants often droop and mass together when lifted from the water. The most satisfactory method for these is to loosen their roots from the mud and float the plant near the surface of the water; insert a sheet of herbarium mounting paper into the water and keep it horizontal just below the surface; float the plant on top of the herbarium mounting paper and arrange its stem, leaves, roots in the desired layout; gently ease the herbarium sheet with its plant specimen in position up out of the water. A sheet of wax paper placed on top of the specimen will prevent it from sticking to the flimsy. Then place the wet herbarium sheet directly into a flimsy and into the plant press. Later in the day, when specimens are placed in a drying press, each should be examined to ensure that the leaves are arranged to show both upper and lower surfaces (not folded or extensively overlapping) and that other parts are included within the confines of the paper. After all of the specimens are placed in the drying press, separated from each other by blotters and ventilators, the press is tightly bound and placed either in the sun or a plant dryer (see Pressing and Drying, below). Data to be recorded for adequate labeling of the specimen A plant specimen is valueless without adequate supporting data on the label. Collectors should provide themselves with a small bound notebook for recording field data at the time of collection. Collections are recorded under a Collection Number assigned to the collection at the time it is gathered and written in pencil, ball-point, or crayon on the outside of the folded newspaper sheet in which the specimen is pressed, dried and kept until mounted. The numbers assigned are ordinarily sequential in numerical order beginning with 1 for each collector. If several duplicate specimens of the same species from the same location are collected on the same day but are placed in separate flimsies, all are given the same collection number. As an alternative to recording collection data in a notebook, all pertinent information maybe recorded on a field collection label (either a plain piece of paper or a label pre-printed with headings for each type of information required) at the time of collection and place the field label with the specimen in the press. Some collectors use tags printed with the same numbers as in the field book and tie one to each plant to prevent mix ups if plants and flimsies become separated.

4 The following data should be recorded in the field notebook or on the field collection labels. The purpose of recording these data in the field is to provide information necessary to label the specimens properly after they are brought in. Do not trust your memory. 1. Name of Collector and Collection number: put this number on all pieces: the specimen, any parts which become detached, in your note book and on any photographs which you take. 2. Date of collection. 3. The name of the plant. If uncertain, make a guess, or describe some of its outstanding characteristics, i.e. yellow Comp. for Composite with yellow flowers. No time is better than the time of collection for the identification of plant specimens. The material is fresh and abundant, and it is possible to determine which features are necessary for the identification of the species, thus collecting only those specimens which can be identified. 4. Distance and direction from the nearest permanent landmark. Indicate as accurately as possible, the kilometers and compass direction from that point (e.g. 5.4 km E of Onefour, AB), or the distance by road (e.g. 2km SW and 3.5km E of Foremost, AB). Section, Township and Range, or Lot, Concession and Township are good location data if you know them, or can add them later. Longitude and Latitude or UTM are essential for geo-referencing and can be obtained from Topographic maps or GPS units (note the map sheet and date or the UTM system used. 5. Country and Province. 6. Habitat Description (e.g. roadside, wheat field, swamp area), including if practicable the conspicuous associated species or community type (grassland, deciduous forest, Larix/Betula swamp, etc.); elevation, exposure (shade or sun), slope and aspect, disturbances, soil texture, moisture regime and drainage conditions (wet, submerged, dry). 7. All morphological features such as flower colour (always note this, because colours often change on drying), annual/perennial habit, scent, height (especially if incomplete plants must be collected), growth form (clumped, growing individually or twining), presence of milky juice, etc. which cannot be ascertained by looking at a dried specimen. Species abundance locally is also useful information. Pressing and Drying the Specimen Leaves of conifers, heaths, succulents, for example, fall when dried, unless previously immersed a few seconds in boiling water. Do not immerse flowers. All loose parts should otherwise be gathered in an envelope, numbered and attached to the mounting sheet. The Plant Press A plant press consists of two press ends or frames enclosing numerous (about 20-30) ventilators and felt botanical dryers (blotters), and secured with a pair of stout straps. Each frame (46cm x 31cm) is constructed of thin strips of hardwood riveted or nailed into a lattice or from a sheet of 1/4 plywood or pressboard. Plywood should be reinforced by gluing or nailing strips of molding 31cm long across the sheet at intervals to prevent warping. The straps should be about 150 cm long to provide for expansion of the press. These can be conveniently constructed using nylon strapping and metal friction-type buckles available at outdoor sporting goods or camping stores. The ventilators are usually corrugated cardboard sheets (46cm x 31 cm) with the flutes opening along the long edge. Botanical dryers are made from dry deadening felt (available at lumberyards or floor covering stores) or from heavy blotting paper also cut to 46 x 31 cm. The usual sequence in a press is corrugated cardboard ventilator, blotter, flimsy containing plant specimen, blotter and corrugated cardboard ventilator, then repeat: blotter, flimsy containing plant specimens, blotter and corrugated cardboard ventilator.

5 Layout of the specimen in flimsies The way the fresh plant goes into the press is the way it will appear when mounted on the herbarium sheet. An ideal dried specimen presents, in two dimensions, the character and appearance of the three-dimensional living plant. Open the flimsy and lay out the specimen on one half. Retain the natural posture of the living plant as much as possible e.g. if the inflorescence normally droops, do not make it appear erect. Have both under surface and upper surface of some leaves face up. Split a bulky specimen. Arrange leaves and flowers so critical characters are not obscured. Have some flowers face up, some face down and some sideways. Arrange the plant so no part overhangs the newsprint folder remembering that a mounting sheet is smaller than a flimsy. Long stems can be folded zigzag two or more times. Stems usually will not break if simultaneously twisted and squeezed when making the sharp bends. The very thick, noncompressable stems or cones of some plants prevent the application of pressure to adjacent structures. Place layers of paper around these structures to allow even pressure application on thinner parts around them. Fold the opened half of the newsprint folder over the specimen. You can use 1 cm thick sheets of foam (upholstery foam) in the place of one of the blotters to achieve the same effect. Sometimes it is necessary to divide a single specimen onto two separate herbarium sheets in order to preserve all the essential or critical parts. The two portions of each specimen are pressed in separate newsprint folders and are given the same collection number plus sheet 1 of 2 and sheet 2 of 2, respectively. Write the collection number on the lower left corner near the hinge of the closed newsprint folder containing the specimen. Adding the genus and species is also recommended. The Coll. No. and the name must correspond with the number and name in the Field Note Book or on the individual field collection label where the supporting collection data is written. Place folders of specimens in plant press Place the numbered newsprint folder with its specimen in the press so it is between two blotters and these are in turn between two corrugated ventilators. Repeat. It is advisable to have all folders oriented the same way in each press. When all folders, etc. have been placed between the frames, put the straps in place and pull tight. The function of a plant press is to apply pressure to flatten the plant specimens and dry them rapidly. The greater the pressure, the greater is the area of contact between plant, newsprint, blotter and ventilator. This speeds up the transfer of moisture from the plant to the ventilator where air passing through the flutes evaporates it. To increase the pressure, stand on the press while tightening the straps. If blotters are unavailable specimens should be separated by additional layers of newspaper. Blotters and extra newspaper must be replaced with dry sheets every day for the first few days. Otherwise, the specimens will discolor and become moldy. Discolored material is undesirable. Moldy material is unacceptable. Drying specimens in the plant press Air movement through the ventilators and gentle heat help dry the plants quickly and minimize discoloration. However, the heat must not exceed about 80 C or 120 F or this will also

6 cause discoloration. A satisfactory source of warm air is to place a 60 or 100 watt desk lamp on the floor and suspend the press above it between two kitchen chairs. To be effective, however, the press must be placed with the flutes vertical so the warm air from the lamp may pass upward through them and speed evaporation. Other sources of moving air or heat include: 1) tie the press on top of a vehicle when traveling in warm, dry weather; 2) place the press in an open window in a building and close the sash onto the press so any air movement must pass through the ventilator flutes; or 3) place on top of a warm radiator. Do not use a household oven; the temperature cannot be controlled well enough at this low range to be useful. Do not risk a fire by using an open flame, kerosene lamp, or space heaters. If a press contains insufficient ventilators, replace wet blotters with dry ones at least every day. Place the wet ones in the sun or over heat until completely dry. Freshly dried, hot blotters remove the moisture from the specimens more rapidly than cold ones. In changing the papers, put the outer specimens inside, so that all specimens dry evenly. When the specimens are completely dry, the folders may be removed from the press and tied in bundles or placed in a box. Most plants will dry in less than a week, but there is considerable individual variation. If the blotters are not changed frequently and dried thoroughly, the specimens will discolor and mold. Fully dried plants no longer feel cold on the cheek, and are stiff and brittle. Once dry, the specimens, in their newspaper flimsies, can be removed from the press and bundled in groups of about 20 for transport back to the home institution. To prevent damage of the dried specimens by insects, which may be hidden in plant parts, all specimens should be treated by freezing at or below -20 C for 48 hours or more, before they are used or stored for research. Mounting Specimens Each specimen eventually will be mounted on acid-free 100% rag paper. Herbarium mounting paper must be of good quality that will not become brittle, fairly heavy to minimize flexing with subsequent breakage of mounted specimens and have a mat surface for adhesion of the glue. The standard size is 29 x 41.7cm (11 1/2 x 16 1/2 inches). The label is glued in the lower right-hand corner. For dissections or special analyses (e.g., chemical, DNA, scanning electron microscopy, pollen analyses), extra flowers, fruits, or vegetative parts are placed loose in a fragment packet, glued to the sheet. The plant specimen should be mounted using white glue (Weldbond is best), cellulose paste or gummed linen tape. Do not use rubber cement, cellulose tape or surgical adhesive tape. Always write your collection number on the mounting sheet as you mount each specimen. Extra flowers should be inserted into a small packet to be fixed to the same page as the specimen, though not overlapping it. Small packets may be folded out of ph neutral bond paper, they should be labeled with your name and collection number. Do not mount duplicate material. Leave the material in the original flimsy with a duplicate archival quality label. Mounting Supplies

7 Plate glass (sheet ca. 12 x 18 ) or an enamel tray smaller piece of plate glass (ca. 5 x 5 ), optional, for putting glue on labels, fragment folders. Glue, a water soluble cellulose Paintbrushes, large and small (e.g. wall, trim, and water colour size are handy) Forceps Dissecting needles Herbarium paper 11 1/2 x 16 1/2, caliper.015 (University of California type), 100% rag, acid neutral (suppliers listed below) Fragment folders, 100% rag, acid neutral Herbarium labels, 100% rag, acid neutral Wax paper Foam Corrugated Cardboard (ca. 12 x 18 ) 5-10 lb sandbag(s) or similar weights Gummed linen tape (for strapping) Needle and linen thread Before beginning, write in pencil the collector and collection number on fragment packets and in the lower right hand corner of the mounting sheet, even if the label is available and will be applied right away. This tiny bit of information is invaluable as a conservation tool if at any point the specimen becomes separated from its label. If the label is unavailable at the time of mounting it is critical that this information is on the specimen. Any tags, field notes or other identifiers should be paper clipped to the sheet as well until the finished label is applied. First arrange your specimens, label and fragment packets on the herbarium sheet to determine the best fit. Before you glue anything, arrange everything so that they will all fit on the sheet of herbarium paper within the allowable margins. This may be tricky: try different orientations of the specimen, different locations for the fragment folder. Try for an arrangement that is aesthetically pleasing as well as of scientific merit. All plant parts should be clearly displayed: leaves (both surfaces), roots, fruits, flowers (both faces and side views). If possible include a few fruits/flowers in the fragment folder; it s especially desirable to include a whole inflorescence rather than individual flowers or fruits. The label should always be placed in the lower right hand corner, and try very hard to leave a spot for the University of Alberta accession stamp at or near the upper right corner. Try to leave room for future annotation labels in the vicinity of the label as well. Linen Tape Method Although this is a time consuming method it is still the most desirable for several reasons. The cloth tape can be cut and removed to allow complete and free access to the specimen without damaging it. Very little of the specimen is in contact with the glue backing and thereby not contaminated by it. There remains enough flexibility that the plant can slide within its bindings somewhat, thus preventing some wear and tear during handling. Since no drying time is required, the specimen processing is complete once the tape is applied. Linen tape is cut into strips of various widths and lengths in advance. I find it easiest to manipulate the strips using curved forceps. Moisten the gummed backing using a moistened sponge. Avoid applying too much water, this causes the glue to take much longer to bind to the paper and can even wash it off completely. Use the strips to tack down the main stem of the specimen in at least 3 or 4 places (depending on size). Use only as many strips as are required to

8 immobilize the specimen. A few extra pieces many be required on parts too close to the edge, or where parts curl up. An important rule of thumb is to fix the plant securely but not to obliterate all examples of a given characteristic. Important features must remain visible. Remember to take small breaks periodically, to stretch and relax your hands. Cellulose Glue Method A dollop of glue is spread out on a sheet of plate glass or in an enamel tray with a fairly wet paintbrush. The desired consistency of the glue is not too runny, but not too sticky. You want to be able to lay your specimen down in it without the glue coming over on to the top side, and you need to be able to slide the specimen off the plate glass without leaving a lot of it stuck to the glass. As you continue mounting you will need to a) brush away plant debris that accumulates, and b) adjust the glue consistency by either adding more water or glue. Once you ve figured how to arrange everything, lay the label onto the plate glass to get glue on the back, remove it from the glue and place it on the sheet of herbarium paper, smoothing out bubbles and mopping up any excess glue with a tissue or paper towel. Lay the plant specimen down gently in the glue and carefully tap down on parts that are not in contact with the glass in order to get glue on all parts of the specimen. Slide the specimen off the glass at an angle of roughly 45 degrees; this seems to be easiest on both the specimen and the mounter. With particularly stiff specimens, such as woody branches, you can hold the plant material up and paint glue directly onto any spots that need it. Place the plant specimen on to the herbarium paper as previously laid out (or as close to that as possible) and blot up any excess glue. Glue on the fragment folder like you did the label. Put the herbarium sheet on a table top or counter and cover it with a sheet of waxed paper, polyurethane foam and a stiff piece of cardboard (e.g. a plant press ventilator), cover with a metal tray or wood sheet for stiffness, and weigh it down with sand bottles. The polyurethane foam is important for cushioning bulky or fragile specimens; for very flat specimens you can get by without it. Remove the sandbags to stack additional specimens, waxed paper, foam, and cardboard, then, replace the weight. Let the glue dry under weight over night. Bulky or stiff material is also strapped with gummed linen tape. Weldbond Glue Method For heavier specimens such as shrub and tree twigs, apply a bead of Weldbond glue to the twig or main stem and root crown. Place in predetermined position on the sheet. Interleave the mounted specimens with sheets of waxed paper, thin foam sheet and cardboard ventilator, and place a weight on top overnight. Weldbond is fast drying. The waxed paper peels off easily when the glue is dry. If necessary, reinforce the mount by tacking loose leaves and flowers with glue or linen strips, after the glue has dried. Many specimens can be mounted using strips of Weldbond glue or gummed linen strips. If using glue, weigh down the plant around the applied glue to prevent warping and to insure a tight bond to the paper. Insure that the bead of glue makes a continuous, but thin, strip across the specimen and contacts the paper at both ends. With linen strips, weights can be omitted, as the

9 gummed adhesive will bond in place within a few seconds. Leave until the glue dries; this usually takes overnight. Weldbond will dry clear and provides a very firm bond which still has some flexibility. Some specimens will need to be reinforced. Sew the twig or branch on to an herbarium mounting sheet with a few stitches of heavy linen thread. Tie each stitch off separately on the underside of the herbarium sheet. The tied ends should be covered to prevent them snagging on specimens beneath. Glue another sheet of herbarium paper underneath or cover the stitches with a strip of linen tape. Tree and shrub branches, conifer cones or large cactus should be mounted on heavier weight herbarium sheets or may require backing with another herbarium sheet. See diagram for additional mounting information. The Label Labels are best prepared with a typewriter or computer printed with water proof ink. Handwritten labels are only acceptable if a) the script is fully legible, and b) it is done in waterproof ink (not felt pen, ball point pen, or pencil) which does not run if it becomes wet nor smear when touched. The herbarium label should be attached to the lower right hand corner of the herbarium sheet. The label information must include: Heading: Name of the Herbarium/ Company or the project/thesis Title : Plants of... (region, province and country) Name: Genus (capitalized) species (lower case), underlined or italicized, Authority Family (optional), Common Name (optional) Location and district, Lat. & Long., Elevation Habitat and Abundance Notes: description of plant (flower colour, habit, height, etc.), if applicable Name of Collector, Collection #, and date Det.: name of person who identified the specimen (i.e. yourself, initials may be used if the same name as the Collector, or the full name of another expert) and the date The format should follow that shown on the label below. It must be printed on plain, ph neutral, unlined white bond paper (not index cards) to a final size of 8cm x 13cm. Additional information: It is an extensive discussion of collections guidelines as set out by the Resources Inventory Task Force, BC Ministry of Environment, Lands and Parks, 1999.

10 University of Alberta Vascular Plant Herbarium (ALTA) Plants of Alberta Epilobium angustifolium L. Onagraceae Fireweed Locality: (should include directional description, map coordinates, legal land description, GIS locations, etc.) Habitat: (should include general habitat description, vegetation type, associated species, slope, aspect, moisture regime, soil type, etc.) Notes: Coll: D. M. Fabijan 986 Date: 18 July 1997 Det.: DMF The following figures illustrate the construction of plant presses.

11 Specimen Mounting All plant parts should be clearly displayed: leaves (both surfaces), roots, fruits, flowers. If possible include a few fruits/flowers in the fragment folder; most desirable is a whole inflorescence rather than individual flowers or fruits. Don t Overlap material Do Knock off loose dirt +/- parts of other plants Throw away parts Fill sheet to margins Plaster with glue Preferred location for fragment folder. Leave 1/2 margin or more if contents will be bulky If possible, leave one or both of these areas clear for annotation labels that may be attached in future.

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