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Fungal endophytes of Oxytropis kansuensis Bunge from China, previously described as Embellisia oxytropis Q. Wang, Nagao & Kakish, and endophytes of Oxytropis sericea Nutt. and Oxytropis lambertii Pursh from the United States were compared and are reported here as conspecific members of a new genus in the Pleosporaceae, Undifilum, based on morphological and molecular analyses. Morphological comparisons revealed characters that are similar to those of the genus Embellisia including conidia ovate to obclavate to long ellipsoid, straight or slightly to decidedly inequilateral with occasionally one or two cells distinctly swollen, and transepta occasionally thickened, dark, and rigid in comparison with the exterior conidium wall. However, upon germination, conidia produced unique and diagnostic germ tubes that were wavy or undulating in their growth until branching. Moreover, all isolates were found to produce the toxic alkaloid swainsonine. Parsimony analysis of sequences from ITS1-5.8S-ITS2, glyceraldehyde-3-phosphate dehydrogenase gene, and mitochondrial small subunit rDNA data sets revealed that the Oxytropis endophytes formed a clade distinct from other Embellisia species and species in the genera Alternaria, Ulocladium, Nimbya, and Crivellia. A second taxon, Helminthosporium bornmuelleri P. Magnus, was reexamined and found to possess similar morphological features to those of the Oxytropis isolates, but lacked swainsonine production. Sequence analysis placed this second taxon in the same clade with high bootstrap support. The distinct morphology and genetics of these taxa demonstrates that these fungi, both recovered from legumes, represent a new genus, hereinafter described as Undifilum. The two species now placed in this genus are redescribed as Undifilium oxytropis and Undifilium bornmuelleri. Les auteurs ont compare les endophytes fongiques de l'Oxytropis kansuensis Bunge de Chine prealablement decrits comme Embellisia axytropis Q. Wang, Nagao & Kakish, et les endophytes de l'Oxytropis sericea Nutt. et de l'Oxytropis lambertii Pursh des Etats-Unis; on en fait des membres conspecifiques le nouveau genre Undifilum membre des Pleosporaceae, base sur des analyses morphologiques et moleculaires. Les comparaisons morphologiques revelent des caracteres similaires a ceux du genre Embellisia, incluant des conidies ovees a obclavees ou ellipsoides, droites ou legerement a nettement inequilaterales, avec occasionnellement une ou deux cellules distinctes et enflees, munies de transepts occasionnellement epais, sombres, et rigides comparativement a la paroi externe des conidies. Cependant, en cours de germination, les conidies produisent des tubes germinatifs uniques et caracteristiques d'aspect sinueux ou a croissance ondulee jusqu'a leur ramification. De plus, on constate que tous les isolats produisent de la swainsonine, un alcaloide toxique. Les analyses en parcimonie des ITS1-5.8S-ITS2, du gene de la deshydrogenase du glyceraldehyde-3- phosphate, et les donnees de la petite sous unite de l'ADN mitochondrial montrent que les endophytes des Oxytropis forment un clade distinct different des autres especes d'Embellisia ainsi que les especes des genres Alternaria, Ulocladium, Nimbya et Crivellia. Les auteurs ont reexamine un second taxons, l'Helminthosporium bornmuelleri P. Magnus et ont constate qu'il possede des caracteristiques morphologiques similaires a celles des isolats des Oxytropis, mais ne produit pas de swainsonine. Les analyses de sequences situent ce deuxieme taxon dans le meme clade avec un fort support bootstrap. La morphologie et la genetique distinctes de ce taxon demontrent que ces champignons, tous deux obtenus de legumineuses, representent un nouveau genre, ici decrit comme Undifilum. Les auteurs redecrivent les deux especes maintenant attribuees a ce genre comme Undefilium oxytropis et Undefilium bornmuelleri. [Traduit par la Redaction], Introduction Locoweed is the common name for a group of toxic plants in the genera Oxytropis and Astragalus (Fabaceae) endemic to arid and semiarid regions of the western USA (Allred [...]

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.