Herbarium

Herbarium a place where collection of dried plant specimens are systematically collected and preserved. Besides classification, the plant specimens are accompanied by information, such as date and place of collection, name of collector, details of habitat, local names, etc.

Every developed country and most developing ones have their national herbaria where the herbarium specimens of the national flora are preserved. Many large international herbaria contain specimens representing plants of countries other than their own. The herbarium situated at Royal Botanic Garden at Kew near London is regarded as the largest with more than 60,00,000 herbarium specimens collected from countries all around the world.

A herbarium at Dhaka was started in the early 1940s when Professor Panchanan Maheshwari, the eminent plant embryologist, was the head of the Biology Department at the university of dhaka. He and his colleagues, and especially an amateur botanist, SK Sen, who was a government servant in the board of revenue, made plant collections from various parts of the region and started building up a herbarium. This is now known as the Dhaka University Herbarium. This collection has been of immense help to teachers and students in teaching and learning about the plants of this region. There are smaller herbaria at the universities of Chittagong and Rajshahi, and at the bangladesh forest research institute (BFRI), Chittagong. The University herbaria cater to the teaching and research of plant taxonomy whereas the BFRI herbarium is devoted to studying the forest flora of Bangladesh. The Chittagong University herbarium is rapidly expanding In the collections there are specimens of the districts of the greater Chittagong and the Chittagong Hill Tracts.

Based on the herbarium collections, floristic accounts (descriptions of flora) of the region are prepared, the distributions of the various species are worked out, and the economic uses of them are recorded. The data on the herbarium labels draw our attention to the abundance of species or its rarity in the country, and thus indicate what immediate measures should be taken to protect endangered species. A herbarium is also a centre of plant identification where all pertinent data regarding any particular species can be obtained. It is an institute where authentic information about the names of plants, the status of any particular species in the wild, and its conservation is available to the public. Recently, Bangladesh National Herbarium has been established at the Botanical Garden, Mirpur, Dhaka. [Md. Salar Khan]

Pests of herbarium Notable among the pests are book lice, silver fish, Almond moth, cigarette beetle, and carpet beetles. The book lice, Liposcelis species of order Psocoptera, family Liposcelidae are small, flat or oval, soft bodied and transparent, yellowish-white insects. The head is large, very mobile, and has compound eyes that are markedly convex, and protrude from the surface of the head. Antennae are filiform and 13-segmented. Both the adult and young are found in herbarium sheets. The young resemble the adult in form and general appearance but are smaller in size and milky-whitish in colour. They are the most damaging of the pests and feed upon starchy portions, glue, paper, labellings, and fragments of dry plant materials.

Silver fish, Lepisma saccharina of order Thysanura, family Lepismatidae, are small, wingless, spindle-shaped apterygote insects. This pest mostly feed upon the glue and labelling of the specimens. The Almond moth, Ephestia cautella (Lepidoptera, Pyralidae) infests the herbarium specimens at the larval stage. Pupation occurs within the herbarium sheets in silken cocoons. It is a serious pest and damage dry plant material by feeding as well as by web-spinning. They also pollute the uneaten portions of herbarium sheets by their silk and excreta.

The cigarette-beetle, Lasioderma serricorne, is a beetle of the family Anobiidae. It is a small robust-bodied insect, oval, and reddish-yellow in colour. The head and prothorax bent downward giving a strong humped appearance when viewed from the side. Females usually deposit eggs on herbarium sheets. After the eggs are hatched, the larvae starts feeding upon them.

The carpet beetle, Anthrenus scrophulariae (family Dermestidae) is also known to infest herbarium specimens at the larval stage. The larvae bore into preserved specimens, by making holes. The black carpet beetle, Attagenus piceus, also infests herbarium specimens. The nature of damage is similar to that of the common carpet beetle. [A Jabber Howlader]