Figures 6-8. Scanning electron micrographs of pollen graiiv; from three species of Erigeron. 6. Erigcron 

 lackschewiuii, x 3500. 7. Erigcron simplex, x 3500. 8. Erigcron ocbrokucus var. scribncri, x 3500. SEM pho(os by 

 Wayne Wamken, Western State college. 



