Sisyrinchium L.
Perianth yellow or rarely blue Sisyrinchium
Perennial or annual with compressed or winged stems, up to 35 cm high. Perianth 10–20 mm diam., yellow or blue to purple. Capsule c. 6 mm diam. Sporadic in a variety of habitats. Introd. from America. Fl. spring–summer. Blue Pigroot Sisyrinchium iridifolium
Annual with only slightly compressed stems, up to 15 cm high. Perianth 5–7 mm diam., yellow. Capsule c. 4 mm diam. Widespread in a variety of habitats. Introd. from S. America. Fl. spring. (Previously included in S. micranthum and may be a subspecies of S. iridifolium.) Scour Weed or Yellow Rush Lily s. A. (