Meloidogyne californiensis n. sp. is described and illustrated from bulrush Scirpus robustus in California. LM and SEM studies revealed that this species differs from other known species in the genus Meloidogyne especially by the prominent posterior cuticular protuberances in the female, the distinct shape of the perineal pattern which is marked by one prominent stria in the perineum, indistinct lateral lines, many broken discontinuous striae on both sides of the arch, and the excretory pore being located posterior to stylet base. Second-stage juveniles 448-628 mum long, stylet length 11-13 mum, styler delicate, with small knobs sloping posteriorly, cephalic region with 2 or 3 annuli, and inflated rectum. Males vary greatly in size (712-1,952 mum), stylet length 18-28 mum (mean 22 mum), cephalic region slightly set off the body with two or three annuli, spear heavy with massive rounded knobs, lateral field marked by four areolated incisures as seen by SEM.
Keywords: Meloidogyne californiensis; Scirpus robustus; bulrush; new species; root-knot nematode; scanning electron microscopy.