A rough estimate indicates that British Columbia possesses approximately 980 species of bryophytes. Of these, mosses (including Spaghnum) form the largest group with ca 740 species, while hepatics number ca. 240 and the hornworts 3. In a Canadian context the province harbours nearly 75% of the bryophytes known from Canada. Approximately 23% of the bryophytes in British Columbia are found (within Canada) only in this province.

This flora is a result of the considerable diversity of climate, combined with a complex geology in all climatic zones. Added to this, floristic elements extending from regions south and north of the province as well as remnant elements of disjunct floras of hyperoceanic, semi-desert and Mediterranean climates makes the area of considerable phytogeographic interest.

In coastal areas with hyperoceanic and relatively mild climates, the sheer luxuriance of bryophytes is impressive. The forest floor often has deep carpets of bryophytes (especially mosses) and tree trunks are often sheathed in mosses while the branches are festooned with them.

This abundance of bryophytes and their diversity makes British Columbia ideally placed to study bryophytes because the abundance is accompanied by a diversity that includes representatives of a high proportion of the major evolutionary lines of bryophytes.