Lobelia linearis, in Afrikaans the sleutelblombos (key flower bush), is a multistemmed shrub of 70 cm to 1 m in height. Multistemmed plants have the woody underround base allowing for resprouting after fire. This plant grows many rigid, erect branches in a grass-like tuft. L. spartioides forms part of L. linearis these days.
The leaves are mainly low on the grey-green stems and sometimes, when in bloom, there are hardly any leaves on the plant at all. Whatever leaves are present, are narrow, linear as the name says, up to 2 cm long and sometimes pinnately divided into thread-like segments.
The species distribution is in the Western Cape from the Cederberg eastwards coastally and through the Little Karoo to the Eastern Cape through the Langkloof to Kareedouw.
The habitat is rocky and sandy fynbos slopes and renosterveld, where rain for the most part arrives in winter and the summers are dry. The species is not considered to be threatened in its habitat early in the twenty first century.
The plants are heavily browsed, especially when the stems are young (Vlok and Schutte-Vlok, 2015; Manning, 2007; Bean and Johns, 2005; http://redlist.sanbi.org).