Hibiscadelphus hualalaiensis
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Hibiscadelphus hualalaiensis is a species of the Hawaiian genus Hibiscadelphus within the mallow family (Malvaceae). It is considered to be extinct in nature.
features
Hibiscadelphus hualalaiensis is a tree that reaches a height of 5 to 7 m. The trunk has a diameter of 30 cm and a white bark. The 10 to 15 cm long, heart-shaped leaf blade is broadly pointed and has a notched base. The leaf surface is covered with star hairs. The leaf stalks are 4 to 10 cm long. The leaf axils bear one or two flowers, the stems of which are 1.5 to 14 cm long. Five serrated bracts are located below each flower and the calyx is tubular or bag-like. The overlapping petals form a bisymmetrical flower and are elongated at the top, which is typical of flowers that are pollinated by birds. The flowers are greenish-yellow outside, inside the greenish-yellow color changes into a purple color. The petals are 2 to 5.5 cm long. The capsule fruit is woody and the seeds are densely hairy. This species differs from other species of this genus by its flower color, the smaller flower size and the serrated bracts.
Distribution, habitat and endangerment
Originally, Hibiscadelphus hualalaiensis was known from three populations on the slopes of Hualālai near Kailua in the Puʻu Waʻawaʻa region on the island of Hawaii . The last known wild tree was in the Puʻu Waʻawaʻa Plant Sanctuary and died in 1992. Previously, however, twelve trees were grown in a fenced area. In addition, there are ten cultivated trees near the State's Kokia Sanctuary in Kaʻūpūlehu . In Kipuka Puaulu in the Hawai'i Volcanoes National Park a reintroduction project was started, but stopped again in order to avoid hybridization with the species Hibiscadelphus giffardianus . Originally, Hibiscadelphus hualalaiensis grew in the remains of dry or semi-arid forests on lava fields at altitudes between 915 and 1020 m. The species formed communities with Diospyros sandwicensis , Sophora chrysophylla , Pouteria sandwicensis , species of the genera Nothocestrum and Charpentiera , Claoxylon sandwicense and Pennisetum clandestinum . The main threats are cattle, pigs and sheep that could break through the fencing, rats that eat the flowers and seeds, competition from invasive plants such as the grass species Pennisetum clandestinum and Lantana camara , habitat changes due to volcanic activities, the risk of extinction due to naturally occurring events such as Fires and the low rate of reproduction due to the fact that all cultivated specimens are clones from a single parent plant.
literature
- Hawaii's Comprehensive Wildlife Conservation Strategy: Flora Fact Sheets - Hibiscadelphus hualalaiensis PDF online
- Warren L. Wagner, Derral R. Herbst, SH Sohmer: Manual of the Flowering Plants of Hawai'i. University of Hawai'i Press, 1999 online version
- Joseph Francis Rock: The indigenous trees of the Hawaiian Islands , 1913: p. 297-299. PDF online
Web links
- Hibiscadelphus hualalaiensis . In: CPC National Collection Plant Profiles . Center for Plant Conservation. Retrieved July 25, 2012.
- Hibiscadelphus hualalaiensis on the IUCN Red List