Lobelia is a genus of flowering plants in the Campanulaceae family comprising 415 species, of which 69 are indigenous to South Africa.

Lobelia linearis, synonymously known as Lobelia lasiantha, Lobelia linearis var. gloveri, Lobelia linearis var. pinnata or Lobelia spartioides and commonly known as Sleutelblombos in Afrikaans or Key Flower Bush in Afrikaans, is a South African endemic species found in the Western Cape from the Cederberg eastwards coastally and through the Little Karoo to the Eastern Cape through the Langkloof to Kareedouw. It grows into a multi-stemmed shrub of 70 cm to 1 m in height. The plants have a woody underground base allowing for resprouting after fire. This plant grows many rigid, erect branches in a grass-like tuft. The leaves are mainly low on the grey-green stems and from time to time, when in bloom, there are hardly any leaves present on the plant. Whatever leaves are present, are narrow, linear as the name says, up to 2 cm long and sometimes pinnately divided into thread-like sections. The habitat is rocky and sandy fynbos slopes and renosterveld, where rain for the most part arrives in winter and the summers are dry.