A Critique on Duthie's Flora of the Upper Gangetic Plain

The base of the Himalaya has failed to provide a workable boundary for the Flora of the Upper Gangetic Plain. Climatically, the sub-mountainous tracts are similar to the Himalayan region and differ markedly from the plains which are drier. Floristic composition of the Himalayan region and that of the sub-mountainous tracts is similar and a large number of plants included in Duthie’s Flora are from these tracts. It is well known that mountainous plants have a wide altitudinal range of distribution and some of these may also be present in sheltered pockets in the submountainous regions but they very rarely reach the hot Gangetic Plain. A list of such plants to support this observation is included.

The base of Siwalik with a definite altitudinal limit is proposed as a more natural, workable boundary for the Upper Gangetic Plain, thus excluding the sub-mountainous tracts. This will result in a compact and stable flora. The inclusion of the sub-mountainous tracts' in the Himalayan region will avoid duplication and will also mean lesser new records or additions to such a Flora.