A 2002 classification of the family Zingiberaceae, based on molecular phylogenetic analysis, placed Roscoea in the tribe Zingibereae, subfamily Zingiberoideae.
It was most closely related to the genus Cautleya, and then to Rhynchanthus, Pommereschea and Hedychium.
The family is mainly tropical in distribution.
The unusual mountainous distribution of Roscoea and the closely related Cautleya may have evolved relatively recently as a response to the uplift taking place in the region in the last 50 million years or so due to the collision of the Indian and Asian tectonic plates.

A molecular phylogenetic analysis of 15 species of Roscoea, based on nuclear ribosomal DNA, showed that the genus was monophyletic, and distinct from the closely related genus Cautleya.
The 15 species fell into two clear groups, a Himalayan clade and a Chinese clade (which includes one species from Burma, R. australis).

The two clades correspond to a geographical separation, the main distributions being divided by the section of the Brahmaputra River which flows south at the end of the Himalayan mountain chain.
Historical biogeography study revealed that evolutionary split between Cautleya and Roscoea occurred during the middle and late Eocene to the early Oligocene, corresponding well to the proposed early uplift of the Himalayas and Qinghai-Tibetan Plateau.
Roscoea species were then divided into two distinct clades, simultaneous with the rapid extrusion of Indochina and accompanied by the another Himalayan uplift around the Oligocene/Miocene boundary.
It has been suggested that the genus may have originated in this area and then spread westwards along the Himalayas and eastwards into the mountains of China and its southern neighbours, supported by biogeographic reconstruction.
Three species have an isolated distribution.
R. brandisii, a member of the Himalayan clade, occurs to the south of the rest of the clade in the Khasia Hills in the modern Indian state of Meghalaya (formerly part of the state of Assam).
R. australis, a member of the Chinese clade, occurs even further south, in the Chin Hills of Burma.
R. ngainoi, discovered after the phylogenetic analysis discussed above, is found roughly between these two species, in the Indian state of Manipur.

The material of R. tibetica included in the analysis came from Chinese sources.
Later research showed that plants from Bhutan and southern Tibet which had previously been considered to be R. tibetica were actually a new species, R. bhutanica, which belongs to the Himalayan clade.
There are few clear-cut morphological differences between the two clades; one is that compared to the Himalayan group, members of the Chinese clade have a larger number of bladeless leaves (i.e. leaves which have only a sheath forming part of the pseudostem).
A 2002 classification of the family Zingiberaceae, based on molecular phylogenetic analysis, placed Roscoea in the tribe Zingibereae, subfamily Zingiberoideae. It was most closely related to the genus Cautleya, and then to Rhynchanthus, Pommereschea and Hedychium. The family is mainly tropical in distribution. The unusual mountainous distribution of Roscoea and the closely related Cautleya may have evolved relatively recently as a response to the uplift taking place in the region in the last 50 million years or so due to the collision of the Indian and Asian tectonic plates.
A molecular phylogenetic analysis of 15 species of Roscoea, based on nuclear ribosomal DNA, showed that the genus was monophyletic, and distinct from the closely related genus Cautleya. The 15 species fell into two clear groups, a Himalayan clade and a Chinese clade (which includes one species from Burma, R. australis).
The two clades correspond to a geographical separation, the main distributions being divided by the section of the Brahmaputra River which flows south at the end of the Himalayan mountain chain. Historical biogeography study revealed that evolutionary split between Cautleya and Roscoea occurred during the middle and late Eocene to the early Oligocene, corresponding well to the proposed early uplift of the Himalayas and Qinghai-Tibetan Plateau. Roscoea species were then divided into two distinct clades, simultaneous with the rapid extrusion of Indochina and accompanied by the another Himalayan uplift around the Oligocene/Miocene boundary. It has been suggested that the genus may have originated in this area and then spread westwards along the Himalayas and eastwards into the mountains of China and its southern neighbours, supported by biogeographic reconstruction. Three species have an isolated distribution. R. brandisii, a member of the Himalayan clade, occurs to the south of the rest of the clade in the Khasia Hills in the modern Indian state of Meghalaya (formerly part of the state of Assam). R. australis, a member of the Chinese clade, occurs even further south, in the Chin Hills of Burma. R. ngainoi, discovered after the phylogenetic analysis discussed above, is found roughly between these two species, in the Indian state of Manipur.
The material of R. tibetica included in the analysis came from Chinese sources. Later research showed that plants from Bhutan and southern Tibet which had previously been considered to be R. tibetica were actually a new species, R. bhutanica, which belongs to the Himalayan clade. There are few clear-cut morphological differences between the two clades; one is that compared to the Himalayan group, members of the Chinese clade have a larger number of bladeless leaves (i.e. leaves which have only a sheath forming part of the pseudostem).
Roscoea