Herbarium: Preparation and Taxonomy

Herbarium specimens are indeed poisoned to prevent fungal and insect attacks, but mercuric chloride (HgCl2) is typically used, not DDT. The other statements are standard practices for herbarium maintenance.

Mercuric chloride (HgCl2) is the standard chemical used for poisoning herbarium specimens to protect them from insects and fungi.

The correct sequence for herbarium preparation is: Collection, Drying, Poisoning, Mounting, Stitching, Labelling, and Deposition.

Herbarium is a store house of collected plant specimens that are dried, pressed and preserved on sheets. Mosses, Lichens and Conifer cones are preserved in the form of herbarium sheets, in their two-dimensional structure.

The floristic study is the study related to the distribution of plants. A herbarium is a collection of preserved plant specimens. It gives the permanent record of plant specimen. The specimens are stored with a data label. The label describes useful information including the plants' scientific name, the origin of the collection, the date and time of collection and the name of the collector. Herbariums are essential for the study of plant taxonomy, the study of geographic distributions and the stabilizing of nomenclature. Herbaria may also be a repository of viable seeds for rare species.

A herbarium is a collection of preserved plant specimens. It gives the permanent record of plant specimen. These specimens may be whole plants or plant parts. These are in a dried form mounted on a sheet. The specimens are stored with a data label. Herbariums are essential for the study of plant taxonomy, the study of geographic distributions and the stabilizing of nomenclature. Herbaria may also be a repository of viable seeds for rare species and new taxonomy

Lectotype refers to the new specimen selected among the original material collected to serve as holotype when the author didn't designate a holotype. It means the type which is declared later from the original material if the type specimen is not described, missing or damaged.

A herbarium is a collection of dried plant specimens carefully preserved and labelled. Plant collections are essential for taxonomic researchers because they serve as voucher specimens. They also help to identify the family. Once mounted and deposited in the herbarium, the collections are referred to as herbarium specimens. Mounting is the process by which a specimen is attached to an herbarium sheet and a label affixed to the lower right corner. Specimens are mounted on sheets of standard size herbarium paper 42 cm x 29 cm.

Labels are pasted on the herbarium sheets over the right-hand bottom. The label should indicate the information about the locality, altitude, habit, date, and time of collection, the name of collector, common name, complete scientific name etc.

The common fungicide used in preventing growth of fungus on herbarium specimens is mercuric chloride. It is highly toxic compound that volatilizes slightly at ordinary temperature and appreciably at 100 degrees Celsius. Mercuric chloride is corrosive to mucous membranes and used as a topical antiseptic and disinfectant. 

A herbarium sheet is a collection of preserved plant specimens. These specimens may be whole plants or plant parts which are usually in dried form mounted on a sheet of standard size 29 × 41.5 cm. 

The herbarium is a quick referral system in taxonomic studies. It is a collection of preserved plant specimens and associated data used for scientific study. So, the correct answer is (C).

Blotting papers must be changed regularly during the drying process to prevent mold and ensure proper preservation. Therefore, statement (iv) is incorrect.

Linnaeus described all plant species known to him in his book “Species Plantarum, 1753” in which he used the system of binomial nomenclature for first time. This makes option A incorrect as not all the plant species were described in this book. The scientific names of species are treated as in Latin regardless of their origin; this makes option C incorrect. According to principle of Priority, names published on or after May 1753 (the date of publication of The Species Plantarum) are considered valid; option B is incorrect. According to principle of typification, holotype is a specimen or illustration which is designated as representative of a species and is used for identification of new specimen. It is mandatory to mention the holotype during publication of new species on or after 1 January 1958; option D is correct. Thus, the correct answer is option D.