The Parc Botanique et Zoologique de Tsimbazaza (PBZT) i is one of the National Center foir Research in madagascar, under the "Ministère de l'Enseignement Supérieur et de la Recherche Scientifique".  It includes four departements : flora, fauna, education to environmental conservation environnementale and administrative and financial departement.
A complete presentation of the Parc of Tsimbazaza is found on PBZT website.

PBZT herbarium is under responsibility of the herbarium division in the flora department. "Tan" is the international acronym (Tananarivo herbarbium, in Antananarivo, Malagasy capital.)

The first Herbarium room was created around 1950 for 40- to 60,000 herbairum sheets. In 1994, this room was full, and a new room was built in 2004 to store the last collections deposited in TAN.

Around 13,000 species of flowering plants, 1,200 bryophytes, 800 ferns are known in Madagascar. TAN herbarium countains more than 265.000 specimen of flowering plants and ferns. It is the largest one for Indian Ocean.
Bryophytes collections were thus ignored because of the lack of specialists. More than 4,000 bryophytes (mosses etc.) specimen are hosted in TAN, and BryoTan project aim to curate them, extract and share data linked to them.