
Orange Bush Monkeyflower, Island Monkeyflower
Diplacus aurantiacus
NATIVE
Description (Jepson, PlantID.net)
- Eudicotyledon
- Eudicots are a major lineage of flowering plants; see family for general characteristics
- Lopseed Family (Phrymaceae)
- Evergreen shrub
- Leaves
- Opposite (2 leaves at each junction with stem)
- Narrow, dark green, and leathery, with prominent veins
- Edges often curled under
- Hairs on paler undersurface
- Distinctly sticky!
- Flowers
- Inflorescence (flower arrangement) of 2-4 yellow-orange flowers at the leaf axils (junction with stem)
- Long, narrow, calyx tube is hairless (glabrous)
- Calyx is the collective term for sepals (usually green, outer flower parts)
- Pedicel (stalk of a single flower) is shorter than the calyx
- Trumpet-shaped, bilaterally-symmetric, with 5 fused petals
- 2 upper lobes stand upright
- 3 lower lobes, often with nectar-guide markings, create a landing platform for pollinators
- Ovary superior (above the attachment of other flower parts)
- Fruit a capsule (a dry, multi-chambered fruit that is dehiscent [splits open]) with 1 seed
- Height to 4 ft.
Distribution
- Native to California
- Grows on rocky hillsides, canyon slopes, disturbed areas, chaparral margins, and open woodlands
- Tolerates serpentine soil
- See Calflora for statewide observations of this plant
- Outside California, grows from southwestern Oregon south into Baja California, Mexico
- Grows at elevations to 2,625 ft.

Uses (San Mateo County Parks prohibits removal of any natural material)
- Wildlife
- Nectar source for insects and hummingbirds
- Larval food source (host) for common buckeye (Junonia coenia) and variable checkerspot butterfly (Euphydryas chalcedona)
- Native people
- Ate the young leaves as salad greens (Ritter 2015)
- Used to treat sores, burns, diarrhea, and eye irritation
Name Derivation
- Diplacus (DIP-la-kus) – from the Greek di, “two,” and plax/plakos, “a disk,” referring to the double placenta of the seed capsule (Ritter 2015)
- aurantiacus (aw-ran-ti-AYE-kus) – from the Latin for “orange”
- Sticky – refers to the resinous leaves
- Monkeyflower – flower shape suggests a mime or monkey
- Sticky monkeyflower used to be in the genus Mimulus, named possibly
- From the Greek mimo, “ape,” because markings on the flowers (or seeds) resemble the face of a monkey
- Or from the Latin mimus, “an actor or mimic,” because the flower resembles the mouthpiece of a grinning mask worn by classical actors
- Sticky monkeyflower used to be in the genus Mimulus, named possibly
Notes
- Leaves are adapted to dry, hot summers of our Mediterranean climate
- Sticky resins help conserve water, as well as prevent browsing
- Curled edges and hairy undersurface limit the loss of water from heat, cold, and wind
- Two-part stigma (pollen-receiving part of the pistil/female structure) closes when touched to capture pollen carried by arriving pollinator and to prevent self-pollination as the pollinator backs out (Breckling 2008)
- If pollen from another flower has not been deposited, the stigma will continue to open and close until pollen is finally received (Borenstein 2010)
- You can induce this closing by lightly pressing the center of the stigma with a fingernail or pencil tip; the stigma will reopen in a few moments
- Diplacus vs Mimulus – In 2018, the scientific name for sticky monkeyflower changed from Mimulus aurantiacus to Diplacus aurantiacus
ID Tips
- Check out this short Jepson video for tips on identifying sticky monkeyflower, called here by an alternative common name, orange bush monkeyflower
- At 1:52 min. into the video, you can see the stigma close when touched
- Edgewood has 3 other monkeyflowers: the diminutive purple mouse-ears (Diplacus douglasii), small-leaved monkeyflower (Erythranthe microphylla), and seep monkeyflower (Erythranthe guttata)
Purple Mouse-ears | Small-leaved Monkeyflower | Seep Monkeyflower | Sticky Monkeyflower | |
Growth Habit | annual herb | annual herb | perennial herb | shrub |
Height | ≤ 1.6 in. | ≤ 1 ft. | ≤ 2 ft. | ≤ 4 ft. |
Flowers | magenta with gold-striped throat | yellow | yellow with orange-red spots | yellow-orange |
Leaves | ovate | elliptic to round | ovate to round | narrowly elliptic to linear |
Habitat | usually serpentine barrens | seeps and streambanks | seeps and swales | coastal scrub, chaparral, woodland openings |
Trails | upper Clarkia and upper Sunset | upper woodland of Edgewood | lower Clarkia | common, especially on lower Clarkia |
At Edgewood
- Found commonly in coastal scrub and open woodlands
- See iNaturalist for observations of this plant
- Flowers March – July
Specific References
Borenstein, C. 2010. Mimulus: Masses of Monkeyflowers.
Breckling, B. 2008. Spring Wildflowers of Henry W. Coe State Park and the Inland San Francisco Bay Area. Pine Ridge Association.
Ritter, M. 2018. California Plants: A Guide to Our Iconic Flora. Pacific Street Publishing, San Luis Obispo, California.
Ross, E.S. 1996. Mimulus aurantiacus. Insect/plant relationships: A photographic essay. Fremontia, April 1996.