Echinochloaconstitutes some of the most prominent weed species found in rice ( Oryza sativaL.) production worldwide. The taxonomy of Echinochloais complex due to its morphological variations. The morphophysiological diversity and taxonomic characteristics of Echinochloaecotypes infesting rice fields in Texas are unknown. A total of 54 Echinochloaecotypes collected during late-season field surveys in 2015 and 2016 were characterized in a common garden in 2017. Plants were characterized for 14 morphophysiological traits, including stem angle; stem color; plant height; leaf color; leaf texture; flag leaf length, width, and angle; days to flowering; panicle length; plant biomass; seed shattering; seed yield; and seed dormancy. Principal component analysis indicated that 4 (plant height, flag leaf length, seed shattering, and seed germination) of the 14 phenological traits characterized here had significantly contributed to the overall morphological diversity of Echinochloaspp. Results showed wide interpopulation diversity for the measured traits among the E. colonaecotypes, as well as diverse intrapopulation variability in all three Echinochloaspecies studied, including barnyardgrass [ Echinochloa crus-galli(L.) P. Beauv.], junglerice [ Echinochloa colona(L.) Link], and rough barnyardgrass [ Echinochloa muricata(P. Beauv.) Fernald]. Taxonomical classification revealed that the collection consisted of three Echinochloaspecies, with E. colonabeing the most dominant (96%), followed by E. crus-galli(2%), and E. muricata(2%). Correlation analysis of morphophysiological traits and resistance status to commonly used preemergence (clomazone, quinclorac) and postemergence herbicides (propanil, quinclorac, imazethapyr, and fenoxaprop-ethyl) failed to show any significant association. Findings from this study provided novel insights into the morphophysiological characteristics of Echinochloaecotypes in rice production in Texas. The morphological diversity currently present in Echinochloaecotypes could contribute to their adaptation to selection pressure imposed by different management tools, emphasizing the need for a diversified management approach to effectively control this weed species.