Malacothamnus marrubioides (Durand & Hilg.) Greene Malacothamnus marrubioides (Durand & Hilg.) Greene in Leafl. Bot. Observ. Crit. 1(15): 208. 1906 sec. Fryxell 1988≡Malvastrum marrubioides Durand & Hilgard, J. Acad. Nat. Sci. Philadelphia, ser. ii. 3: 38. 1855 syn. sec. Fryxell 1988