Pentagramma rebmanii
Rebman's silverback fern, Rebman's Silverback Fern
(c) Trevor Van Loon, some rights reserved (CC BY) · licence
Family: Pteridaceae · Type: Perennial · Native
Conservation status: CNPS 1B.3
Pentagramma rebmanii (Rebman's silverback fern) is a native California perennial in the Pteridaceae family, recognized by subtle differences in gland density and exudate characteristics.
Rebman's silverback fern is a rare (CNPS 1B.3) California native perennial found in southern San Diego County in seasonally moist, shaded, rocky slopes at elevations of 450 to 1,250 meters. This distinctive fern features a rhizome with unique white-scaled tips and blade surfaces covered in sparse to dense white exudate. Growing with ternate leaf structures where lower pinnae are approximately as wide as long and range 2 to 5 centimeters in length, the fern has deeply lobed pinnae with asymmetrical basal configurations. Its leaf blades are not sticky on the upper surface but display intricate white powdery coating, particularly on the undersides. The fern's complex leaf architecture, with pinnae that are deeply pinnately lobed almost to the point of being one-pinnate, makes it a distinctive species in its habitat.
Identification and appearance
Key characters: 3 sympatric species; subtle differences in gland density and exudate characteristics
Habitat and range
Habitat: Seasonally moist, shaded, rocky slopes
Elevation: 450-1250 m
Outside California: nw Baja California
Conservation status
CNPS 1B.3
How to tell it apart
vs Pteridium: Pentagramma is small (<30 cm) and stays in rock crevices; Pteridium is tall (>50 cm) and spreads in open areas.; vs Polypodium: Pentagramma fronds are finely divided multiple times; Polypodium fronds are simple with one row of undivided leaflets.; vs Dryopteris: Pentagramma has golden/silver coating underneath; Dryopteris undersides are green with kidney-shaped spore covers.; vs Aspidotis: Pentagramma segments attach broadly; Aspidotis segments are bead-like with edges rolled under to protect spores.; vs Myriopteris: Pentagramma undersides are smooth or waxy; Myriopteris undersides are fuzzy with hairs or scales.
Frequently asked questions
Is Pentagramma rebmanii native to California?
Yes. Pentagramma rebmanii is native to California (recorded as native).
What plant family does Pentagramma rebmanii belong to?
Pentagramma rebmanii is in the Pteridaceae family, genus Pentagramma.
Is Pentagramma rebmanii rare or endangered?
Pentagramma rebmanii carries California Rare Plant Rank 1B.3, state rank S3.
What habitat does Pentagramma rebmanii grow in?
Pentagramma rebmanii grows in Seasonally moist, shaded, rocky slopes.
Related species
Other California species in the same genus, family, or bioregion.
- Pentagramma sp. — Goldback or silverback fern
- Pentagramma triangularis — Goldback fern
- Pentagramma viscosa — Coastal silverback fern
- Pentagramma glanduloviscida — San diego silverback fern
- Pentagramma maxonii — Desert silverback fern
- Pentagramma pallida — Frosty silverback fern
- Pteridaceae sp. — Brake family
Sources: Jepson eFlora · CNPS Rare Plant Inventory · Index of California Plant Names · CalPhotos · CDFW CNDDB
Last updated 2026-09-30
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.