Common St. Johnsworth
St.johnswort, also known as Klamath weed, is a member of the St. johnswortfamily. It is an introduced, creeping perennial which reproduces byseeds and short horizontal roots. The multi-branched stems are 1 to 2 ½feet tall and emerge from a woody base.
Leaves are opposite, elliptic to oblong, with translucent dots alongthe leaf margins. The bright yellow flowers have five petals which haveblack dots along their margins, an occur on showy terminal clusters.
St.johnswort is an aggressive invader of overgrazed rangeland. It is foundon gravelly or dry sandy soils. This plant may be toxic to white-hairedanimals (causes photosensitization), such as white-faced sheep.