CPC Plant Profile: Hidden Lake Bluecurls
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Plant Profile

Hidden Lake Bluecurls (Trichostema austromontanum ssp. compactum)

Image of Trichostema austromontanum ssp. compactum Photo Credit: Naomi Fraga
  • Global Rank: T1 - Critically Imperiled
  • Legal Status: N/A
  • Family: Lamiaceae
  • State: CA
  • Nature Serve ID: 145928
  • Date Inducted in National Collection:

Trichostema austromontanum subsp. compatcum (Hidden lake bluecurls) is a member of the mint family (Lamiaceae). This taxon is very small and is only about 10 cm tall. Hidden Lake blue curls is known to occur at one location in the world, in the San Jacinto Mountains in Riverside, County. Trichostema austromontanum subsp. compatcum occurs in a special habitat along the margins of a vernal lake and blooms in the late summer (July-August) when the lake has receded and has started to become dry.

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  • 10/01/2020
  • Demographic Research

Demographic study of T. a. subsp. compactum (Naomi Fraga & Ken Kietzer)

  • 09/01/2020
  • Orthodox Seed Banking

Based on an September 2020 extract of the California Plant Rescue Database, California Botanic Garden holds 9 accessions of Trichostema austromontanum subsp. compactum in orthodox seed collection. There are as many as 72514 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, California Botanic Garden has collected 9 seed accessions of Trichostema austromontanum subsp. compactum from 1 plant occurrences listed in the California Natural Diversity Database. These collections together emcompass 589 maternal plants

Nature Serve Biotics
  • 05/02/2017

Endemic to a single vernal pool - the only naturally occurring body of water in the San Jacinto Mountains of southern California, at about 2400-2500 meters. The entire range of this subspecies is an area of less than 1 hectare. The population fluctuates from year to year depending on rainfall; it varied from 11 to 10,000 individuals over an 11-year period. The site became accessible and extremely popular for recreation with construction of a tramway in 1964. Since then the plants have been subjected to more severe trampling by horses and hikers.

Terry Higgins, Naomi S. Fraga
  • 01/01/2010

Trichostema austromontanum subsp. compatcum was previously threatened by trampling (from horses and humans) caused by recreational use at the lake (USFWS 1998). Trampling by horses crushed plants and creates small depressions that retain water (Bauder 199

Terry Higgins, Naomi S. Fraga
  • 01/01/2010

The population has been documented to be as large as 27,000 individuals in 2008, to as few as 75 individuals in the year 2000 (CNDDB 2011, Fraga & Wall 2008). The population appears to decline during periods of above and below normal precipitation (Bauder 1999). This is due to lack of suitable habitat (a narrow band along the margin of Hidden Lake) and suitable conditions for germination (Bauder 1999).

Terry Higgins, Naomi S. Fraga
  • 01/01/2010

Demographic study of T. a. subsp. compactum (Naomi Fraga & Ken Kietzer)

Terry Higgins, Naomi S. Fraga
  • 01/01/2010

The park has reduced visitation to the area (by both humans and horses) by removing references to Hidden Lake from trails, maps, and signs in the park, and obscuring trails to the lake (USFWSa 2006) Additionally, the Park has installed a low wooden barrier to exclude equestrian use. Finally, the Park has closed the Hidden Divide Natural Preserve to cross country travel, an activity allowed elsewhere in the Park, making it a citable offence for unauthorized individuals to visit the lake as there are no designated trails which arrive at Hidden Lake. Rules for visitors to the Hidden Lake Divide Natural Preserve include no camping or picnicking and hikers must stay on designated paths. Pets are not allowed in the Wilderness and pack animals are not allowed off trail.

Terry Higgins, Naomi S. Fraga
  • 01/01/2010

Transplant Experiments: investigate and develop a protocol to transplant this taxon for future recovery efforts. Propagation experiments: investigate and develop protocol to grow plants up to reproductive maturity in a nursery setting. Genetic diversity of Hidden Lake bluecurls: level of genetic diversity is not known for T. a. subsp. compatcum. An understanding of the genetic diversity within the single known population of this taxon will greatly aid in any future recovery efforts. Identify additional research needs as progress toward conservation proceeds: additional research objectives and needs may include research on the effects of climate change for T. a. subsp. compatcum and an additional study of this taxons evolutionary history.

Terry Higgins, Naomi S. Fraga
  • 01/01/2010

Maintain the maternal line seed collections at Rancho Santa Ana Botanic Gardens seed storage facility. Life history assessment ; conduct germination trials to determine optimal conditions for germination of this species. Assess the genetic diversity and population structure of the species to facilitate appropriate seed sampling and establish criteria that will trigger management actions.


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Taxon Trichostema austromontanum ssp. compactum
Authority F.H. Lewis
Family Lamiaceae
CPC Number 4318
ITIS 32371
Common Names Hidden Lake Bluecurls | San Jacinto bluecurls
Associated Scientific Names Trichostema austromontanum ssp. compactum
Distribution Trichostema austromontanum subsp. compatcum is mainly restricted to the margins of Hidden lake. The entire known range of T. a. subsp. compatcum encompasses an area of 0.8 ha (2 ac) (Bauder 1999). T
State Rank
State State Rank
California S1

Trichostema austromontanum subsp. compatcum is restricted to one locality on the southeastern flank of the San Jacinto Mountains; Hidden Lake, Riverside County, California (Bauder 1999, CNDDB 2011). This sole occurrence of T. a. subsp. compatcum lies within both Mount San Jacinto State Wilderness Area and Hidden Divide Natural Preserve. Hidden Lake (also known as Lake Surprise prior to 1910) is a small montane vernal lake (0.97 hectares [2.4 acres]) that sits at 8700 ft (2650 m) in elevation and is 2.5 air miles ESE of San Jacinto Peak. The lake occupies a small shallow depression that is underlain by granite derived solids (Rodgers 1967). The adjacent slopes rise to ca. 8,800 ft (2,682 m) on the north and south sides of the lake and are a source of water via runoff from rain and snow. The water level of the lake fluctuates markedly depending on the available moisture and time of year (Bauder 1999). During exceedingly wet years, the lake may remain filled for multiple years, and in years of drought the lake may be completely dry leaving the soil of the lake basin exposed for extended periods of time (Bauder, 1999). The basin effectively functions as a small vernal lake or depressional wetland with an annual hydrological cycle of shallow inundation from precipitation and interflow from adjacent uplands followed by a lengthy period of exposure (Bauder 1999). Hidden Lakes maximum depth is reported to be 4.3 ft (1.3 m) (Bauder 1999). There is a single location where water flows out of the lake located at the southwest corner of Hidden Lake.

Ecological Relationships

Trichostema austromontanum subsp. compatcum has no documented pollinators and has been found to be self-compatible (89.1% seed set with the exclusion of pollinators) (Spira 1980). Spira (1980) also found that insects visiting the con-specific taxon T. a. subsp. austromontanum lacked pollen grains on their ventral surface (which is needed for the transfer of pollen to stigma), and therefore were not acting as effective pollinators (Spira 1980). This suggests that flowers of this species are not commonly pollinated by insects and are generally self-fertilized.Associated species include: Crassula aquatica (water pygmyweed), Cyperus squarrosus (bearded flatsedge), Eleocharis bella (beautiful spikerush), Gnaphalium palustre (western marsh cudweed), Lotus nevadensis (Nevada birds foot trefoil), Calyptridium parryi var. parryi (Parrys pussypaws), Juncus bufonius. (toad rush), J. duranii (Durans rush), Muhlenbergia f iliformis. (pullup muhly), Limosella acaulis (Owyhee mudwort), Mimulus breweri (Brewers monkeyflower), M. floribundus (manyflowered monkeyflower), M. pilosus (false monkeyflower), M. suksdorfii (Suksdorfs monkeyflower), and Veronica peregrina. subsp. xalapensis (hairy purslane speedwell).

Common Name Name in Text Association Type Source InteractionID
Lead Institution State Reintroduction Type Year of First Outplanting

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