Cirsium fontinale
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| Cirsium fontinale E. Green |
Cirsium fontinale or Fountain thistle is an flowering perennial herb of the Asteraceae family, endemic to a limited region within northern and central California at an elevation not exceeding 750 meters. Occurrences appear limited to serpentine seeps and streams within portions of the San Francisco Bay Area and Outer South Coast Ranges. The Cirsium genus is commonly known as the "thistle" genus, Cirsium being the Greek word for thistle. There are three recognized varieties of this species:
- Cirsium fontinale (E. Greene) Jepson var. fontinale, Fountain Thistle, Federal and State of California Endangered
- Cirsium fontinale (E. Greene) Jepson var. campylon, Mount Hamilton Thistle, Federal candidate for listing
- Cirsium fontinale (E. Greene) Jepson var. obispoense, Chorro Creek Bog thistle, Federal and State of California Endangered
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[edit] Morphology common to all Cirsium fontinale taxa
All the taxa within Cirsium fontinale have erect stems with leaves very strongly wavy margins.[1] These tall plants may attain a height of 2.2 meters, but may exist in the form of only 0.5 meters. A given plant may have one or more stems, and the plants are sometimes short-lived, dying after flowering only once, even though the species is acknowledged to be perennial. Lower leaves are typically petioled or tapered, but mostly spiny-lobed; petioles are either spiny-lobed or toothed.
Inflorescences are characterized by prickly heads more or less grouped in a panicle-like cluster, closely subtended by the higher leaves. involucres are either hemispheric or bell-shaped, with purple to green coloration. Phyllaries range from a lanceolate to ovate shape. There are characteristically many flowers with white, pink or lavender corollae about 20 millimeters in length. Anther bases are sharply sagittate, with oblong tips; the ends of the styles manifest a somewhat swollen node, with a cylindrical superior appendage. The smooth brownish fruits are four to five millimeters in diameter, but distinctly ovoid; many pappus bristles are exhibited.
[edit] Range and distinct features of var. fontinale
Cirsium fontinale var. fontinale, Fountain Thistle, occurs only in four colonies within San Mateo County at elevations of approximately 120 meters, which implies a distribution on the lower slopes of the Montara Mountain Block, within the Santa Cruz Mountains foothills. Historically this variety occurred in a broader range throughout San Mateo and Santa Clara County.[2] Habitats are seeps, wetlands and riparian areas associated with serpentine soils. This variety of Cirsium fontinale was the first to be listed as endangered by the state of California (July, 1979).[3]
The stem of Fountain Thistle is generally less than 1.3 meter in height and reddish in color. Leaves are distinctly glandular and thinly tomentose. The inflorescence heads are generally nodding when in bloom, but typically are erect in the fruiting stage. The outer reddish phyllaries are 15 to 20 millimeters in size, and are somewhat recurved: these structures are wider above the middle, but abruptly tipped with a one to two millimeter spine. The corolla tube extends 10 millimeters, with a throat dimension of five to six millimeters and lobes approximately the same size; the style branches have a dimension of three to four millimeters. The ovoid fruits are smooth, and chromosomes are characterized as: 2n=34 +1.
[edit] Range and distinct features of var. campylon
Cirsium fontanale var. campylon is uncommon, but occurs throughout the San Francisco Bay Area in Santa Clara, San Mateo, Marin, Sonoma, Alameda and Contra Costa County. Elevations of this variety are from 300 to 750 meters, which implies occurrence on the upper elevations of the Santa Cruz Mountains, Sonoma Mountains, Mayacamas Mountains as well as the inner coastal mountains of the east bay. As with the other species varieties, the Mount Hamilton Thistle prefers moist areas on serpentine slopes including seeps, stream environments and other wetlands. For example, one colony is found on serpentine soil along the east side of Upper Crystal Springs Reservoir. This species is a candidate species for listing on the federal endangered species list.[4]
Morphological differences of the Mount Hamilton Thistle compared to other varieties of this species manifest first in a green stem which has a maximum height of two meters. The leaves of var. campylon are densely tomentose and glandular hairs are not evident. Compared to the other varieties Mount Hamilton Thistle's flowering heads are strongly and permanently nodding; moreover, its outer phyllaries present a greenish color and have a length of 20 to 30 millimeters. The phyllaries are distinctly recurved and channeled, with the widest dimension below the middle; the upper phyllary element becoming a spine of three to five millimeters. Corolla tubes are five to six millimeters long with a throat of double the tube; lobes are four toe five millimeters and style branches are about the same size as lobes. Fruits are ovoid and smooth.
[edit] Range and distinct features of var. obispoense
The Chorro Creek Bog Thistle variety occurs only in limited portions of the Outer South Coast Ranges of central Caliornia within San Luis Obispo County. As with other subspecies it prefers riparian or seep areas, typically on slopes; its occurrence is associated with Chorro Creek. It is found at elevations less than 300 meters. The Chorro Creek Bog Thistle was listed as a federally endangered species on December 15, 1994 and is classified as endangered for its entire range.[5]
The green to purplish stem of var. obispoense is always less than two meters in height, producing densely tomentose leaves, particularly for lower surfaces. When in bloom, the flowering heads have a nodding habit, but at the fruiting stage, they are erect. The plant's outer green to dark purple phyllaries are of dimension 15 to 20 millimeters; moreover these structures are strongly recurved and somewhat channeled, with the upper half tapering to a one to four millimeter spine. The corolla tube of Chorro Creek Bog thistle is seven millmeters in size with a throat ever so slightly larger; the lobes are approximately five millimeters and the style banches of approximately the same scale. Fruits are smooth, ovoid and minutely scabrous above.
[edit] References
- ^ Jepson Manual, University of California Press (1993)
- ^ Sacramento Fish & Wildlife Office, Species Account: Cirsium fontinale var. fontinale, Recovery Plan for Serpentine Soil Species of the San Francisco Bay Area, September 30, 1998
- ^ [http://www.dfg.ca.gov/bdb/pdfs/TEPlants.pdf State of California listing of endangered species, October, 2006
- ^ Earth Metrics Inc., Report of endangered species search and vegetative survey of the Polhemus Property at the northeast corner of the intersection of Ralston Avenue and State Route 92, San Mateo, prepared for San Mateo County, California, July, 1989
- ^ U.S.Fish and Wildlife Service listing details for Chorro Creek Bog Thistle
