Statistical and Scanning Electron Microscopical investigations were carried out to study trichome initiation during leaf development in Pelargonium scabrum (L.) L'Herit. It is evident that leaf growth in P. scabrum can be divided into different stages of epidermal cell differentiation and enlargement, and trichome initiation. Glandular hairs are initiated continually during leaf growth, although at varying rates during the different stages of leaf development, while spiny hairs are initiated in the young leaf only. Because the rate of glandular hair initiation is lower than that of epidermal cell differentiation and enlargement, the indumentum becomes less dense with leaf expansion.
