Two new species of Undifilum, fungal endophytes of Astragalus (locoweeds) in the United States.

New species of Undifilum, from locoweeds Astragalus lentiginosus Vitman and Astragalus mollissimus Torr., are described using morphological characteristics and molecular phylogenetic analyses as Undifilum fulvum Baucom & Creamer sp. nov. and Undifilum cinereum Baucom & Creamer sp. nov. Fungi were isolated from dried plants of A. lentiginosus var. araneosus, diphysus, lentiginosus, and wahweapensis collected from Arizona, Oregon, and Utah, USA, and A. mollissimus var. biglovii, earleii, and mollissimus collected from New Mexico, Oklahoma, and Texas, USA. Endophytic fungi from Astragalus locoweeds were compared to Undifilum oxytropis isolates obtained from dried plant material of Oxytropis lamberteii from New Mexico and Oxytropis sericea from Arizona, Colorado, New Mexico, Utah, and Wyoming. Extremely slow growth in vitro was observed for all, and conidia, if present, were ellipsoid with transverse septa. However, in vitro color, growth on four different media, and conidium size differed between fungi from Astragalus spp. and U. oxytropis. Neighbor-joining analyses of internal transcribed spacer (ITS) region and glyceraldehyde-3-phosphate dehydrogenase (GPD) gene sequences revealed that U. fulvum and U. cinereum formed a clade distinct from U. oxytropis. This was supported by neighbor-joining analyses of results generated from random amplified polymorphic DNA (RAPD) fragments using two different primers.