Species: Centaurea solstitialis Traditional Cache
Species: Centaurea solstitialis
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This cache is located in the Cronan Ranch Regional Trails Park in Pilot Hill, California.
It is another in a series of educational caches that combines geocaching and my love of nature.
"I have never let my schooling interfere with my education." -Mark Twain-
Kingdom: Plantae -> (unranked): Angiosperms -> (unranked): Eudicots -> (unranked): Asterids -> Order: Asterales -> Family: Asteraceae -> Tribe: Cynareae -> Genus: Centaurea -> Species: C. solstitialis

This cache is hidden in an example of Yellow Starthistle (Centaurea solstitialis), is a member of the family Asteraceae, native to the Mediterranean Basin region. The plant is also known as golden starthistle, yellow cockspur and St. Barnaby's thistle (or Barnaby thistle) The plant is a thorny winter annual species in the knapweed genus.
Description
Centaurea solstitialis is an annual herb from the Asteraceae family. During the vegetative stage if forms a rosette of non-spiny leaves (5–20 cm diameter). As the summer approaches, it produces a flowering stem (1 m) which will produce numerous spinous capitula containing numerous (10-50) yellow flowers. Flowers within capitula are pollinated by insects and each capitula will produce a mix of (10-50) pappus and non-pappus seeds. It is an annual semelparous species, and will die after reproduction is completed, normally by the end of the summer.
Ecology
Centaurea solstitialis is a weed also on its native European range (e.g. Turkey, Greece, Italy, France, Spain), consequently, it inhabits highly disturbed ruderal habitats, being typically found on roadsides and cereal crop margins. After introduction in several parts of the world as an exotic species (e.g. Australia, Argentina, Chile, USA), it has developed local adaptations to the different habitats colonized, and an incipient level of reproductive isolation between native and non-native ranges has been detected. This makes this species a candidate case for incipient ecological speciation.
Invasive species
Centaurea solstitialis grows as a balanced part of the ecosystems in Eurasia, where it is kept in check by an assortment of natural herbivore enemies and other plants that have co-evolved with it in its native habitat. However, it has been introduced in several parts of the world, including Australia, Argentina, Chile, and the USA.[2] In many of these non-native regions, where the particular array of natural biological controls found in the native regions do not exist, it has become an invasive species and noxious weed.
Species introduction
The introduction of Centaurea solstitialis in North America probably occurred in California sometime after the start of the California Gold Rush, as a fodder seed contaminant in imported Chilean-harvested alfalfa seed, also known as Chilean clover (Trifolium macraei). Introduction in other parts of the world is poorly known. In California, Yellow star-thistle was dispersed into agricultural fields, and immediately took hold in the state's Mediterranean-type climate areas. Human factors, such as mowing, land grading for development and roads, domestic animal grazing, and disturbance of the soil surface for agricultural tillage and wildland firebreaks have and continue to contribute to the successful thriving and spread of this plant. Yellow starthistle is now a very common sight in vacant lots and fields, along roadsides and trails,in pastures and ranch lands, and in parks, open-space preserves and natural areas.
Wikipedia has more related links about Centaurea solstitialis. .
Cache Information:
The cache is a regular sized cache hidden in amongst a field of Centaurea solstitialis. Parking and a restroom are located near by. The terrain rating may be elevated to a 4.5 if you look for this cache during the summer in shorts and sandals.
Please log your find or no find online so I will know how the cache is doing. If you feel my coordinates are off please post your coordinates with your log. So I can make adjustments if necessary.
Additional Hints
(Decrypt)
Qba'g sbetrg gb ybt gur pnpur
Treasures
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