A nomenclatural type is the element to which the name of a taxon is permanently attached, whether as the correct name or as a synonym. Types are the anchor voucher specimens for a name of species and of great importance in plant taxonomy to ascertain the scientific names of plants. There are various classes of type specimens such as holotype, isotype, syntype, lectotype, isolectotype, neotype, paratype and epitype.  

The Herbaria (ARUN, ASSAM, BSA, BSD, BSHC, BSI, BSID, BSIS, BSJO, CAL, MH and PBL) of Botanical Survey of India (BSI) are one of the main attractions for the botanical research program throughout the world and houses approximately 3 million specimens, collected from all around the world. Type specimens are one of the important collections and these are our primary botanical collections. These collections have been consulted by researchers throughout the world either by visiting to our herbaria or by digital images.

BSI is committed to make this important collection available online free of cost, hence, the digital images of all the type specimens housed at different herbaria of BSI are now freely accessible. This section offers an online access to about 26100 type collections of Phanerogams from about 50 countries. Out of them, about 21000 type specimens are housed at CAL.