|
''Pterospora'', commonly known as pinedrops, wooodland pinedrops, Albany beechdrops, or giant bird's nest is a North American genus in the subfamily Monotropoidiae of the blueberry family, and includes only the species ''Pterospora andromedea''.〔(【引用サイトリンク】title= United States Department of Agriculture plants profile: ''Pterospora andromedea'' Nutt. )〕〔(Biota of North America Program 2014 county distribution map )〕 It grows in coniferous or mixed forests. It is widespread across much of Canada as well as the western and northeastern United States to and northern Mexico (Sonora, Coahuila, Durango, Nuevo León).〔(SEINet, Southwestern Biodiversity, Arizona chapter )〕 Along with ''Monotropa'' it is one of the more frequently encountered members of the Monotropoidiae.〔(Flora of North America, ''Pterospora'' Nuttall, 1818. )〕 The genus name is derived from the morphology of the seeds which have narrow flaps of tissue on the side and therefore appear winged: ''ptero'' (Gr.) = winged, ''spora'' (Gr.) = seed. The specific name ''andromedea'' derives from the resemblance of the flowers to those of another genus in the Ericaceae, ''Andromeda''.〔〔 The visible portion of ''Pterospora andromedea'' is a fleshy, unbranched, reddish to yellowish flower spike (raceme) 30–100 cm (12-40 inches) in height, though it has been reported to occasionally attain a height of 2 meters (5 feet). The above-ground stalks (inflorescences) are usually found in small clusters between June and August. The inflorescences are hairy and noticeably sticky to the touch. This is caused by the presence of hairs which exude a sticky substance (glandular hairs). The inflorescences are covered by scale-like structures known as bracts. The upper portion of the inflorescence has a series of yellowish, urn-shaped flowers that face downward. The fruit is a capsule.〔 Like all members of the Monotriopoidiae (see ''Monotropa''), ''Pterospora andromedea'' lacks chlorophyll (trace amounts have been identified, but not enough to provide energy for the plant or to color it). Plants exist for most of their life as a mass of brittle, but fleshy, roots. They live in a parasitic relationship with mycorrhizal fungi, in which plants derive all their carbon from their associated fungus, but the relationship is not yet well understood. The term for this kind of symbiosis is mycoheterotrophy. In ''Pteropspora'' the association is with a very limited number of fungi in the genus ''Rhizopogon'', including ''Rhizopogon subcaerulescens, R. arctostaphyli'', and ''R. salebrosus''. A note of caution: unlike plants, fungi are not yet well categorized and so species' names are likely to change frequently as more research is done and ''Rhizopogon'' is particularly hard to taxonomically categorize. ''Pterospora'' has yet to be discovered with any species outside the genus ''Rhizopogon''.〔〔KW Cullings, TM Szaro, TD Bruns. 1996. "Evolution of extreme specialization within a lineage of ectomycorrhizal epiparasites" - Nature 379:63-65〕 ''Pterospora'' has consistently been shown to be more closely related to ''Sarcodes'' than any other member of the Monotropoidiae.〔 ==See also== * ''Corallorhiza'' 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Pterospora」の詳細全文を読む スポンサード リンク
|
