Records of vascular plants (flowering plants, grasses, rushes, sedges and ferns) are kept in the OHBR database and then forwarded annually to the county recorder to be checked before being submitted to the NBN database via the Botanical Society of Britain and Ireland. The flora of the Outer Hebrides is comparatively well recorded, although many of the records are old. A number of local recorders are involved in botanical recording and have contributed records for the next edition of the Atlas of the British Flora.

Records of marine and freshwater algae, including desmids, cyanobacteria (blue-green algae) and diatoms form part of the OHBR database and appear on the NBN Atlas Scotland.

The marine algae are comparatively well recorded, and the current list of 389 species is over 60% of the documented UK seaweed flora. In comparison very little information is available about the composition and distribution of the freshwater algae, desmids, cyanobacteria and diatoms. The Outer Hebrides Algae website catalogues and illustrates the species recorded during recent fieldwork by OHBR.

Records of bryophytes (mosses and liverworts) are also included in the OHBR database and are forwarded to the county recorder to be checked before being submitted to the NBN database via the British Bryological Society.