Saxifrage Family

Species of the saxifrage family are prominent in certain habitats in North America. The genera are described below, with particular reference to species occurring in North America.

The most diverse group is the saxifrages. The swamp saxifrage (Saxifraga pensylvanica) occurs in wet meadows, bogs, and moist woods over much of eastern North America, while the early saxifrage (S. virginiensis) occurs in dry forests and rocky habitats. Most species, however, are alpine or arctic in their distribution. Relatively widespread species that occur in both alpine and arctic tundras include the purple mountain saxifrage (S. oppositifolia), golden saxifrage (S. aizodes), spider-plant (S. flagellaris), prickly saxifrage (S. tricuspidata), snow saxifrage (S. nivalis), and bulblet saxifrage (S. cernua).

The lace flowers or foam-flowers occur in moist woods and include Tiarella cordifolia of eastern North America and T. trifoliata and T. unifoliata of western North America.

Miterworts occur in moist woods and bogs. Mitella diphylla and M. nuda occur in the east, while M. pentandra is in western North America.

Several species of grass-of-parnassus occur in cool, open, wet places, including the widespread northern grass-of-parnassus (Parnassia palustris).

Currants and gooseberries are shrubs that occur extensively in boreal and temperate habitats. The bristly black currant (Ribes lacustre), northern black currant (R. hudsonianum), skunk currant (R. glandulosum), and northern red currant (R. triste) all occur widely in boreal and montane habitats. More temperate species include wild black currant (R. americanum), gooseberry (Ribes hirtellum), swamp currant (R. lacustre), and golden currant (R. odoratum).

The hydrangea (Hydrangea arborescens) is another native shrub in the saxifrage family that occurs in southeastern North America.