Wikipedia
Arundinoideae
The Arundinoideae are a subfamily of the true grass family Poaceae with around 40 species, including giant reed and common reed. Unlike many other members of the PACMAD clade of grasses, the Arundinoideae all use C photosynthesis. Their sister group is the subfamily Micrairoideae.
Arundinoideae used to be quite large in older taxonomic systems, with over 700 species, but most of them have been moved to other subfamilies following phylogenetic analyses. Currently, species are placed in 16 genera and two tribes.