
Serpentine Linanthus
Leptosiphon ambiguus
NATIVE – CA ENDEMIC
Description (Jepson, PlantID.net)
- Eudicotyledon
- Eudicots are a major lineage of flowering plants; see family for general characteristics
- Phlox Family (Polemoniaceae)
- Annual herb
- Stem generally erect, threadlike, and branching
- Leaves
- Opposite (2 leaves at each junction with stem), appearing whorled
- Small pairs are widely-spaced along stems
- Palmately compound (separate leaflets radiating from a single point) with deeply-cleft, needle-like leaflets
- Opposite (2 leaves at each junction with stem), appearing whorled
- Flowers
- Inflorescence (flower arrangement) usually solitary from leaf axil (junction with stem) or a few-flowered cyme (a flower cluster on which the central or terminal flower blooms first)
- Long flower stalks (peduncles) to 2 in.
- Funnel-shaped flower with 5-petaled, dish-like face (salverform)
- Petals lavender to pink
- Throat ringed white to yellow, with violet below
- Stamens (male flower parts) with yellow-orange pollen are exserted (extending beyond petals)
- Ovary superior (above the attachment of other flower parts)
- Inflorescence (flower arrangement) usually solitary from leaf axil (junction with stem) or a few-flowered cyme (a flower cluster on which the central or terminal flower blooms first)
- Fruit a capsule (a dry, multi-chambered fruit that splits open at maturity)
- Height to 8 in.

Distribution
- Native and endemic (limited) to California
- Grows in valley grassland, foothill woodland, and northern coastal scrub, generally on serpentine soils
- 95% of plants occur on ultramafic soils, e.g.serpentine; see ultramafic affinity rankings (Calflora per Safford and Miller 2020)
- See Serpentine Grassland for more about Edgewood’s serpentine soil and the unique communities it supports
- See Calflora for statewide observations of this plant
- California Rare Plant Rank: 4.2 (Watch list: limited distribution or infrequent throughout a broader area in California)
- Grows at elevations to 3,280 ft.
Uses (San Mateo County Parks prohibits removal of any natural material)
- No documented wildlife or human uses found for this species
Name Derivation
- Leptosiphon (lep-toe-SY-fon) – from the Greek leptos, “slender,” and siphon, “tube”
- ambiguus (am-BIG-yoo-us) – from the Latin ambiguus, “uncertain” or “ambiguous,” possibly referring to its uncertain relationship with other Leptosiphons with more typical, compact flowerheads
Notes
- Previously in the genus Linanthus
- Linanthus – from the Greek linon, “flax,” and anthos, “flower”
- Often still used in common names for Leptosiphon species
ID Tips
- May be confused with 3 other species of Leptosiphon at Edgewood, along with one non-native member of the Flax family (Linaceae), narrow-leaved flax (Linum bienne)
- Small-flowered leptosiphon (L. parviflorus), Edgewood’s most common species
- Common leptosiphon (L. androsaceus)
- Flax-flowered leptosiphon (L. liniflorus)
Serpentine Leptosiphon | Small-flowered Leptosiphon | Common Leptosiphon | Flax-flowered Leptosiphon | Narrow-leaved Flax | |
Inflorescence | few-flowered spray | many-flowered head | many-flowered head | few-flowered spray | few-flowered spray |
Flower Shape | flat, open-face … funnel | flat, open face … very long, narrow funnel | flat, open face … long, narrow funnel | cupped to open face … short funnel | cupped to open face … no funnel |
Floral Tube Length | ≤ 0.24 in. | ≤ 1.8 in | ≤ 1.3 in | ≤ 0.08 in. | … |
Petal Color | lavender to pink | white to cream¹ … often with 2 red dots at yellow base | pale lavender to pink | white … purple veins | white to blue … purple veins |
Pollen Color | yellow-orange | yellow-orange | yellow-orange | yellow-orange | blue |

© AFengler (LL, LM, R), SBernhard (M), KKorbholz (RM)

© LMiller
At Edgewood
- Found in serpentine grasslands
- No iNaturalist observations are documented because locations of rare species are obscured
- Flowers March – June
Specific References
Alexander, E.B. 2010, Oct. & 2011, Jan. Serpentine soils and why they limit plant survival and growth. Fremontia 38/39: 28-31.
Miller, L.B. 2004. Linanthus ambiguus [Illustration of Leptosiphon ambiguus, adapted]. T. Corelli. Flowering Plants of Edgewood Natural Preserve (2nd. ed.). Monocot Press, Half Moon Bay, California. (c) CC BY NC 3.0.
—–. Linanthus androsaceus [Illustration of Leptosiphon androsaceus, adapted]. T. Corelli. Flowering Plants of Edgewood Natural Preserve (2nd. ed.). Monocot Press, Half Moon Bay, California. (c) CC BY NC 3.0.
—–. Linanthus liniflorus [Illustration of Leptosiphon liniflorus, adapted]. T. Corelli. Flowering Plants of Edgewood Natural Preserve (2nd. ed.). Monocot Press, Half Moon Bay, California. (c) CC BY NC 3.0.
—–. Linanthus parviflorus [Illustration of Leptosiphon parviflorus, adapted]. T. Corelli. Flowering Plants of Edgewood Natural Preserve (2nd. ed.). Monocot Press, Half Moon Bay, California. (c) CC BY NC 3.0.
—–. Linum bienne [Illustration, adapted]. T. Corelli. Flowering Plants of Edgewood Natural Preserve (2nd. ed.). Monocot Press, Half Moon Bay, California. (c) CC BY NC 3.0.
Safford, H.D. 2010, Oct. & 2011, Jan. Serpentine endemism of the California flora. Fremontia 38/39: 32-39.
Safford, H.D. and J.E.D. Miller. 2020. An updated database of serpentine endemism in the California flora. Madroño 67: 85-104. BioOne Complete.