Overview
Many-flowered navarretia is an annual herb of the phlox family with pale blue flowers. This extremely rare subspecies is found only on substrates of volcanic origin and is dependent on vernal pools, vernal lakes and swales for survival. Its life history is closely linked to the hydrology of these wetlands. As of 2009, there were seven known occurrences of this subspecies; five in Lake County and two in Sonoma County, which are potentially extirpated.
The primary threats to this subspecies include wetland drainage, off-highway vehicle use, effects from road maintenance activities, residential development, competition from invasive weedy plant species, climate change climate change
Climate change includes both global warming driven by human-induced emissions of greenhouse gases and the resulting large-scale shifts in weather patterns. Though there have been previous periods of climatic change, since the mid-20th century humans have had an unprecedented impact on Earth's climate system and caused change on a global scale.
Learn more about climate change , small population size, and risk of localized stochastic extirpations.
Many-flowered navarretia was listed as endangered on June 18, 1997.
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Characteristics
Physical Characteristics
Many-flowered navarretia forms mats 2.0 to 7.9 inches across and 0.4 to 1.2 inches high. The stems have a peeling, white surface and are highly branched. Stem thickness is 0.03 to 0.06 inch and is more or less uniform throughout its length. The leaves are 1.2 to 1.6 inches long and are either entire or have a few thread-like lobes. Flower heads are 0.6 to 0.8 inch across and contain between 10 and 60 pale blue flowers. Each flower in the head is 0.20 to 0.24 inches long. Each fruit may contain as many as three seeds. The fruit of this species is a papery capsule that breaks open only when wet.
Life Cycle
Little is known about the life history and demography of many-flowered navarretia. Like many vernal pool annuals, its seeds germinate underwater and flower after the pools dry. The plants flower in May and June. The flowers are probably insect-pollinated. Navarretias with similar flowers that occur outside of vernal pools are pollinated by a variety of bees and bee flies, although other insects may visit to collect nectar.
Habitat
Many-flowered navarretia is found in pools that form on volcanic substrate, specifically in Northern Basalt Flow and Northern Volcanic Ashflow Vernal Pools. Typical many-flowered navarretia is found only at Boggs Lake. The lake itself is classified as a northern volcanic ashflow vernal pool which consists of a clay layer that is impervious to water and is buried under a layer of volcanic ash. The soil at Boggs Lake is in the Collayomi-Aiken-Whispering complex. Elsewhere, Many-flowered navarretia occurs in vernal pools, vernal lakes and swales.
Areas such as marshes or swamps that are covered often intermittently with shallow water or have soil saturated with moisture.
Timeline
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