Root hairs are thought to play an important role in the uptake of water and nutrients from the environment. Several root hair defective mutants were isolated from Mutator-tagged stocks and EMS-mutagenized lines of maize. These mutants all condition either non-elongated root-hair initials (rth1, rth3-1, rth3-2, rth3-3, rth4, rth5, rth6) or shorter-than-normal root hairs (rth2). The morphology of rth1, rth2, and rth3 root hairs were analyzed via SEM. The rth1, rth2, and rth3 genes map to chromosomes 1L, 5L, and 1S, respectively. The rth3 gene was cloned using Mu-tagged allele. The partial cDNA sequence of this gene suggests that it may be a cell wall protein. In addition, an rth1 candidate gene was cloned. This gene contains, 25 exons and encodes a protein with similarity to yeast proteins involved in protein trafficking.