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Lessingia germanorum
''Lessingia germanorum'' is a rare species of flowering plant in the daisy family known by the common name San Francisco lessingia. It is endemic to California, where it is known from four populations in the Presidio of San Francisco and one occurrence on San Bruno Mountain south of San Francisco.〔(California Native Plant Society Rare Plant Profile )〕 It is a state and federally listed endangered species. The already rare plant is endangered by many processes, including invasive species, development, sand mining, off-road vehicles and bulldozers, habitat fragmentation, trampling, and pollution, as well as stochastic events.〔US Fish & Wildlife Service. (Endangered status for the plant ''Lessingia germanorum'' (San Francisco Lessingia) from California ). ''Federal Register'' 62:118. June 19, 1997.
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This is an annual herb producing a decumbent to erect, reddish stem no more than 30 centimeters long. The deeply lobed leaves are up to 3 or 4 centimeters long. Some leaves and new stem parts are coated in woolly fibers. The inflorescence is a solitary flower head or cluster of heads at the tip of the stem. The bell-shaped involucre is lined with pointed phyllaries that curl back as the head matures. The head is discoid, with no ray florets but several tubular golden disc florets with raylike lobes. The plant blooms in July through November.〔(Golden Gate National Recreation Area: 2008 Endangered Species Big Year )〕 The fruit is an achene with a whitish pappus.
This plant grows in beach sand dunes and scrub and similar sandy habitat. It is native to the tip of the San Francisco Peninsula, a land mass which is intensely developed and urbanized.〔 The single population known on San Bruno Mountain near Daly City was discovered in 1989 and is threatened by the construction of houses in the immediate vicinity.〔 The largest population of the plants is in the dunes at the mouth of Lobos Creek in the San Francisco Presidio.〔 Habitat in the area is infested with non-native species such as ice plant (''Carpobrotus'' sp.), which produces mats of herbage over the sand dunes, stabilizing the sand; the lessingia requires shifting, windblown sand habitat.〔 Introduced trees have also altered the habitat of the lessingia. Old Monterey cypress (''Cupressus macrocarpa'') and Monterey pine (''Pinus radiata'') planted many decades ago remain in the Presidio dunes; these native California trees are not native to this particular ecosystem, and have become detrimental.〔Schwartz, K. (2005). (Effectively restoring the San Francisco dune ecosystem and protecting endangered species: Why removing a plantation of invasive trees is necessary. ) UC Davis Ecology.〕
==References==
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
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