Make a Plant Collection - Arasi Lawrence Company

Make a Plant Collection

The plants should always be collected as complete as possible, a small herb always with root. Of trees and shrubs a branch with well-developed leaves, if possible also with flowers or fruits, will do.

If the plants could not be pressed immediately after the collecting, they ought to be put in a closed vessel in order to keep fresh. In olden days the cylindrical vasculum of metal belonged to any herborization. Nowadays this is largely replaced by a nylon-bag. Especially in a hot country like Egypt with a burning sun during most of the excursions, the nylon-bag has proved to have great advantages. It does not get hot like a vasculum; it is easy to carry and to handle and, in addition, keeps the plants fresh, even for several days, when well closed. The types of bags used at the Cairo University are large, of square form, with an attached strap to be carried over the shoulder. They are closed by means of a zip-fastener.

For the pressing any stiff flat board with a heavy weight on will do. At our university we use the Swedish standard model for plant presses made out of wood. For field purpose a portable iron press with leather strips of the model found in the market will serve its purpose. A field press may also be made at home of 2 cardboard or wooden plates and a leather strap.

The best paper for pressing is any cheap porous paper of the market like newspaper, meat paper, blotting paper. Between every plant ought to be at least 2-3 empty papers to get the moisture better out of the fresh material. The papers should be changed often and replaced by dry ones. One has to change papers at least 3-4 times for an ordinary plant, more if the plant is fleshy. It is advisable to dip fleshy plants in boiling water for ½ - 1 minute before pressing. They dry quicker that way.

The student often asks, how long time a plant has to stay in the press. A small herb may be dry after a few days, a succulent first after some weeks. As a rule, a plant is ready when it feels crisp and not cool when touched.

In order to protect the plants from insect attacks, it is advisable to dip them in poison before they are finally taken out of the press. The solution most commonly used for this purpose consists of: 150g mercury chloride and 350g ammonium chloride, dissolved in as little water as possible, and to this added 10 litres of 96% alcohol. For private use 15g, 35g, and 1 litre are sufficient quantities to start with.

After poisoning the plant may remain in press still a day or two in order not to get wrinkled. It is then ready to be mounted. It could be fixed to any stiff paper by means of strips of gummed paper. At our university we use strips of such rolls of gummed paper that can be obtained from the market and which are used instead of strings for closing packages.

Finally comes the labelling. There is a general rule that the label should be fixed in the lower right corner. The labelling of a plant is most important, and great care has to be taken to do this properly. The Latin name should first be written, followed by the family name in case it is the herbarium of a beginner. For advanced collections there is no need of family name. After this should follow the exact locality, type of habitat and date of collecting, eventually also a remark on flower colour, vernacular name or other information of interest. The name of the collector should be put at the bottom of the label, and in case one person is the collector and another determines the plant, the two names should be put on the label, preceded by: Leg. (= legit, collected by), and Det. (= determinavit, determined by), the terms generally used for this purpose.

Source: STUDENTS’ FLORA OF EGYPT second edition, by VIVI TÄCKHOLM, D. Sc. (Stockholm) Professor of Systematic Botany, Faculty of Science, Cairo University. Published by Cairo University. Printed by COOPERATIVE PRINTING COMPANY Beirut, 1974.

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