Erythranthe rubella is a species of monkeyflower known by the common name little redstem monkeyflower. It was formerly known as Mimulus rubellus.
It is native to western North America, including the southwestern United States to Wyoming and Texas, and into Baja California.
Erythranthe rubellus is an annual herb growing 2 to 32 centimeters tall with a very slender, red stem. The oppositely arranged oval leaves are up to 3 centimeters long and lance-shaped to oval, the lower ones borne on short petioles. The herbage is usually lightly hairy and green to reddish in color.
The petite tubular flower is no more than a centimeter long, the base of its tube encapsulated in a narrow, ribbed calyx of sepals. The flower may be yellow or pink in color and the mouth of the flower is usually dotted with red or purple.
^ Barker, W.R.; Nesom, G.L.; Beardsley, P.M.; Fraga, N.S. (2012), "A taxonomic conspectus of Phrymaceae: A narrowed circumscriptions for Mimulus, new and resurrected genera, and new names and combinations" (PDF), Phytoneuron, 2012–39: 1–60CS1 maint: uses authors parameter (link)
^ Beardsley, P. M.; Yen, Alan; Olmstead, R. G. (2003). "AFLP Phylogeny of Mimulus Section Erythranthe and the Evolution of Hummingbird Pollination". Evolution. 57 (6): 1397–1410. doi:10.1554/02-086. JSTOR 3448862.
^ Beardsley, P. M.; Olmstead, R. G. (2002). "Redefining Phrymaceae: the placement of Mimulus, tribe Mimuleae, and Phryma". American Journal of Botany. 89 (7): 1093–1102. doi:10.3732/ajb.89.7.1093. JSTOR 4122195. PMID 21665709.
^ Beardsley, P. M.; Schoenig, Steve E.; Whittall, Justen B.; Olmstead, Richard G. (2004). "Patterns of Evolution in Western North American Mimulus (Phrymaceae)". American Journal of Botany. 91 (3): 474–4890. doi:10.3732/ajb.91.3.474. JSTOR 4123743. PMID 21653403.