CPC Plant Profile: Pine Hill Flannelbush
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Plant Profile

Pine Hill Flannelbush (Fremontodendron decumbens)

This closeup shows the flower of this flannelbush in detail. Photo Credit: Dieter Wilken
Description
  • Global Rank: G1 - Critically Imperiled
  • Legal Status: Federally Endangered
  • Family: Malvaceae
  • State: CA
  • Nature Serve ID: 141870
  • Date Inducted in National Collection: 03/06/1993

This species of flannelbush cannot self-pollinate but has a fascinating relation with the three native bee species that pollinate its flowers. The bees are attracted to the high levels of ultraviolet light the flowers reflect. The nectar they produce absorbs UV light (appearing darker to the bees) and then reflects some of it in visible wavelengths with the brightness proportional to the amount of nectar present. This allows the foraging bees to determine when another pollinator has recently visited a flower from a distance and increases the chance that the bee will visit flowers that have not been pollinated. (Boyd 1985) Pine Hill Flannel Bush is a member of the cacao family (Sterculiaceae). Members of this family include the tropical and subtropical plants that are used to make cola, chocolate and various drugs. Some plants are also used as ornamental in garden plants. This family is noteworthy because of its evergreen leaves. The name Flannel Bush alludes to the fuzzy-feeling leaves of this particular plant. These fuzzy leaves have tiny hairs covering their whole surface, which keeps Fremontodendron decumbens from losing too much water from its leaves. This is a very important adaptation in the hot and drought-prone areas in California where this plant grows.

Participating Institutions
Updates
  • 09/01/2020
  • Orthodox Seed Banking

Based on an September 2020 extract of the California Plant Rescue Database, University of California Botanical Garden holds 1 accessions of Fremontodendron decumbens in orthodox seed collection. There are as many as 349 seeds of this species in their collection - although some may have been used for curation testing or sent to back up.

  • 09/01/2020
  • Orthodox Seed Banking

Based on an September 2020 extract of the California Plant Rescue Database, California Botanic Garden holds 5 accessions of Fremontodendron decumbens in orthodox seed collection. There are as many as 1862 seeds of this species in their collection - although some may have been used for curation testing or sent to back up.

  • 08/05/2020
  • Seed Collection

Based on an August 2020 extract of the California Plant Rescue Database, University of California Botanical Garden has collected 3 seed accessions of Fremontodendron decumbens from 2 plant occurrences listed in the California Natural Diversity Database. These collections together emcompass 26 maternal plants

  • 08/05/2020
  • Seed Collection

Based on an August 2020 extract of the California Plant Rescue Database, California Botanic Garden has collected 1 seed accessions of Fremontodendron decumbens from 1 plant occurrences listed in the California Natural Diversity Database. These collections together emcompass an unknown number of maternal plants

Nature Serve Biotics
  • 05/02/2017

Narrowly endemic to a gabbroic soil area in western El Dorado County, California. The plants are scattered within an area of approximately 18 sq mi and are vulnerable to destruction by development and to the long-term effects of fire suppression due to their proximity to current and planned residential and commercial development projects. Trash dumping and road construction are also threats.

  • 01/01/2010

Fire suppression (Boyd 1985) Development Road Construction Trash Dumping (NatureServe 2001)

  • 01/01/2010

One extended population at Pine Hill that is managed by the CA Dept. of Forestry. Another small population has been recorded south of Grass Valley (Nevada Co), CA. Regional Parks Botanical Garden has collected seed which is stored at RSA.

  • 01/01/2010

Walter Knight published an article on the successful cultivation of this species at Regional Parks Botanic Garden in 1996. Robert S. Boyd published a number of articles describing the fascinating reproductive biology of this species. (Boyd 1966, 1985, 1987, 1992, 1994, 1996, 2001)

  • 01/01/2010

The largest population is protected by the Pine Hill Ecological Preserve although there have been attempts by the state to sell portions of it for development, the populations are still relatively intact due to pressure from concerned citizens and botanists.

  • 01/01/2010

Research needed includes the determination of habitat requirements for the species pollinators (solitary bees). Management needs include managing for these pollinator populations and developing/maintaining a fire regime to promote seed germination for the species.

  • 01/01/2010

Off-site study needed for this species includes determining its genetic diversity.

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Photos
Nomenclature
Taxon Fremontodendron decumbens
Authority R.M. Lloyd
Family Malvaceae
CPC Number 1952
ITIS 502666
USDA FRDE2
Common Names Pine Hill flannelbush
Associated Scientific Names Fremontodendron decumbens | Fremontodendron californicum subsp. decumbens | Fremontodendron californicum ssp. decumbens
Distribution Western El Dorado County, California (NatureServe 2001)
State Rank
State State Rank
California S1
Habitat

Tops of rocky ridges and on scattered rock outcrops of gabbro in chaparral communities or in the ecotone between chaparral and woodland. (NatureServe 2001)

Ecological Relationships

Both the flower buds and the flowers themselves suffer high levels of damage from two species of moth larvae (only 10% of buds survive to become flowers and only half of all flowers survive to produce fruit). The fruit are fuzzy which deters these two species from feeding but a third undescribed species bores holes into the fruit to eat the seeds. Despite starting out with up to 5600 buds at the beginning of the process, most plants only produce 100-200 seeds in a growing season. These seeds are dropped into the surrounding litter and rodents consume 90% of new seeds each year. Harvester ants disperse these seeds which have a small bit of tissue, a caruncle, attached to their coat that the harvester ants eat. These ants take the seeds back to their mounds, eat the caruncle and toss them out to the area surrounding their mounds. This effectively disperses the seeds up to 25 feet from where they fall. The surviving seeds will germinate when they are heated by fire. (Boyd 1985)

Pollinators
Common Name Name in Text Association Type Source InteractionID
Bees
Stingless bees Tetralonia stretchii Confirmed Pollinator Link
Leaf-cutting bees Callanthidium illustre Confirmed Pollinator Link
Sweat bees Halictidae Floral Visitor Link
Honey bees Apis mellifera Floral Visitor Link

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