Known from fewer than ten occurrences. Threatened by fire suppression, non-native plants, recreational activities, and road maintenance.. Equals T. macrophylla var. agnina; USFWS uses this name. See T. macrophylla var. macrophylla in The Jepson Manual (1993). See Annals of the Missouri Botanical Garden 81(4): 719 (1994) for species account.