Within 1 yr of collection, 60% or more of false broomweed (Ericameria austrotexana M. C. Johnst.) seed germinated at continuous temperatures from 15 to 30C if light was provided for 8 h daily. Maximum radicle elongation and fresh weight of 14-day-old seedlings occurred at 25 and 30C. Alternating temperatures did not enhance germination, and germination was suppressed in the dark. Germination, time required for germination, and early seedling vigor were tolerant of CaCl2 and MgCl2 solutions at concentrations as high as 200 mM, but NaCl reduced germination at concentrations in excess of 100 mM. Germination was sensitive to polyethylene glycol solution osmotic potentials of 0.6 mPa or more. Reduced germination in salt solutions was attributed to an osmotic effect rather than a direct effect of ions. Other than an inability to germinate when soil water is limited, no narrow environmental requirements appear to restrict establishment of this undesirable rangeland shrub.
