A collective phyllome structure that consists of two or more of the most distal perichaetal bracts on a gametophore axis and surround a capsule. [source: ISBN:0962073342]
Comment
The perichaetal bracts may fuse laterally in the gametophytic perianth. The gametophytic perianth is not the same structure as a perianth (PO:0009058) in angiosperms.