The present study has been undertaken on phenology, pollen morphology, and the effect of environmental temperatureon pollen viability of four woody species (Cordia boissieri, Parkinsonia texana, Parkinsonia aculeate and Leucophyllum frutescens) in northeast Mexico. These four species started flowering from March till June during this month they are in fruiting stage. Large variations were observed on pollen morphology with respect to form, size, and surface ornamentations of pollen grains. The species varied widely in pollen viability percentage in response to the prevailing environmental temperatures. Although, at 23°C the species showed high pollen viability, Cordia boissieru (81.22%), Parkinsonia aculeate (80.11), Parkinsonia texana (79.40). and Leucophyla frutescens 73.79%) but with an incease in temperature pollen viability decreased down to about 60%). The temperature 23°C was found to be favorable for optimum pollen viability (80%) of all the species studied. With an increase in temperature, C. boissieri showed drastic decrease in pollen viability, while the pollen viability remained more or less stable, but decreased at 32°C.