Click the number at the start of a key lead to highlight both that lead and its corresponding lead. Click again to show only the two highlighted leads. Click a third time to return to the full key with the selected leads still highlighted.
1 Floral tube obtusely 3-angled, greenish to creamy white; flowers in a capitate cluster (solitary in depauperate individuals)
..2 Flowers blue, with perianth lobes paler and sometimes cream; basal leaves absent
..2 Flowers yellow or greenish; basal leaves present