| Heterotheca oregona var. rudis (Greene) Semple | Semple, J. C., C. Leeder, C. Leuty & L. Gray. 1988. Heterotheca sect. Ammodia (Compositae: Astereae): a multivariate study of H. oregona and specimens of Brewer's (golden) aster. Syst. Bot. 13: 547–558. | 88-89 | 9II | |
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