| 词条 | Wilkesia gymnoxiphium |
| 释义 |
| image = Wilkesia gymnoxiphium2.jpg | image_caption = Wilkesia gymnoxiphium growing near Waimea Canyon | regnum = Plantae | unranked_divisio = Angiosperms | unranked_classis = Eudicots | unranked_ordo = Asterids | ordo = Asterales | familia = Asteraceae | genus = Wilkesia | species = W. gymnoxiphium | binomial = Wilkesia gymnoxiphium | binomial_authority = A.Gray, 1852[1] | status = EN | status_system = IUCN3.1 }}Wilkesia gymnoxiphium (Hawaiian iliau), is a species of flowering plant in the sunflower family, Asteraceae, that is endemic to the island of Kaua{{Okina}}i in Hawai{{Okina}}i. It is classified as endangered on the IUCN Red List.[2] Wilkesia is one of three genera, with Argyroxiphium (silverswords and greenswords) and Dubautia (a larger group with many varied species) that are believed to be descendant from a single species related to the North American tarweed.[3] The members of these three genera constitute what is called the silversword alliance, a group whose exceedingly close genetic heritage is not reflected in their exceptionally diverse morphologies.[4] DescriptionW. gymnoxiphium is a monocarpic rosette shrub, with rosettes elevated on woody stems as much as {{Convert|5|m|ft|abbr=on}} tall. Distinctive features include a usually unbranched, monocarpic axis, leaves in whorls of 9-15 that join to form a basal sheath around the stem, and peduncles that are commonly branched. Fountains of yellow, daisy-like flowers form mostly May to July. When unbranched the plant dies after flowering, but if it branches into multiple heads (as may happen if the top is broken off), each head will flower and die separately. HabitatThis species occurs only on Kaua{{Okina}}i, on dry ridges or dry to mesic forests. The most common location is along the slopes of Waimea Canyon. It grows at elevations of {{Convert|425|-|1100|m|ft|abbr=on}} in areas that receive {{Convert|800|-|2000|mm|in|abbr=on}} of annual precipitation. Heavily grazed by feral goats in the canyon, they are most often seen on inaccessible slopes. However, a dense population can be seen in a fenced enclosure just off the road heading to Kōke{{Okina}}e State Park. References1. ^{{GRIN | accessdate=2009-10-31}} {{Taxonbar|from=Q8002480}}{{DEFAULTSORT:Wilkesia Gymnoxiphium}}{{asteroideae-stub}}2. ^{{Cite web|url=https://www.iucnredlist.org/species/97910910/97911062|title=The IUCN Red List of Threatened Species|website=IUCN Red List of Threatened Species|access-date=2018-11-23}} 3. ^{{cite book|last=Carlquist|first=Sherwin|title=Hawaii, a natural history: geology, climate, native flora and fauna above the shoreline|publisher=Pacific Tropical Botanical Garden|location=Lawai|year=1980|pages=250–266}} 4. ^{{cite web|title= Adaptive Radiation and Hybridization in the Hawaiian Silversword Alliance |url= http://www.botany.hawaii.edu/faculty/carr/habit.htm |work=|publisher=University of Hawaii Botany Department|accessdate=December 8, 2009}} 5 : Madieae|Endemic flora of Hawaii|Biota of Kauai|Plants described in 1852|Taxa named by Asa Gray |
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