类似 Hypericum perforatum
Several native Hypericum spp. exist that look similar to H. perforatum, but are usually distinctive with at least one of the following morphological characteristics: prostrate growth pattern, linear leaves with acute tips, small basal sterile shoots, and leaves folded along midrib (CDFA, 2005).
Canary Island St. John's wort (Hypericum canariense) is an ornamental shrub with a height of 4-6 meters making it much larger than the common St. John's wort(CDFA, 2005). The leaves are also much narrower in H. canariense than in H. perforatum, and the sepals in H. canariense have marginal hairs(CDFA, 2005).
Dwarf St. John's wort (Hypericum mutilum) like its name implies is a smaller plant, about half the height of common St. John's wort, with one-chambered capsule unlike the common St. John's wort which has a three-chambered capsule (CDFA, 2005). The dwarf St. John's wort is not as common, but its range is expected to expand and is currently associated with moist or riparian habitats (CDFA, 2005).