Gerrit van Iterson Jr (Roermond, August 19, 1878 – Wassenaar, January 4, 1972) was a Dutch botanist and professor who developed a mathematical approach to plant growth (phyllotaxis).
The grounds for splitting Cotyledon to create the new genus included certain features of the flowers, but more conspicuously, the leaves of Tylecodon are deciduous in summer and they are borne in a spiral arrangement, rather than the opposite, decussate arrangement of Cotyledon leaves.