Oxalis Triangularis Plant. Depending on the variety you have, the triangular leaves can be the plain green type, or they also come with dark purple leaves like my own plant. The striking purple leaves stand out amongst green indoor plants and it’s also photophilic, which mean that the leaves open and close in response to light in a process called nystinasty.
False shamrock, love plant, purple shamrock, wood sorrel. This plant’s foliage consists of trifoliate leaves (compound leaf with 3 leaflets). Each leaf has the shape of a little heart, but is triangular like butterfly wings.