Ko'oko'olau (Bidens wiebkei)
|Listed||October 8, 1992|
|Description||Perennial herb with flower heads on side branches.|
|Habitat||Steep, exposed slopes in mesic shrublands and forests.|
|Threats||Habitat disturbance, predation by feral or domestic animals.|
Bidens wiebkei (also known as ko'oko'olau), a perennial herb of the aster family that is woody at the base, reaches a height of 1.6-3.3 ft (0.5-1 m). The opposite, pinnately compound leaves are 2.8-5.1 in (7.1-13 cm) long; individual leaves are comprised of three to seven leaflets, each 1-3 in (2.5 cm-7.6 cm) long and 0.4-l in (1-2.5 cm) wide. The flower heads are arranged on side branches in clusters of usually 10-30. Each flower head is 0.6-1 in (1.5-2.5 cm) in diameter and is comprised of four to six sterile yellow ray florets, all about 0.5 in (1.3 cm) long and 0.08-0.2 in (2-5.1 mm) wide. The flower heads also possess nine to 18 bisexual yellow disk florets. The one-seeded fruit of this plant is a brownish-black achene that is curved or twisted and winged; it is about 0.2-0.4 in (5.1-10.2 mm) long and 0.04-0.08 in (1-2 mm) wide. This particular species is distinguished from other members of Bidens by its erect habit and the curved or twisted winged achenes.
The five known populations of B. wiebkei are scattered along steep exposed slopes in mesic shrub-lands and forests at 820-3,450 ft (249.9-1,051.6 m) in elevation.
Other associated plant species include Antidesma (hame), Nestegis sandwicensis (olopua), Pisonia (papala kepau), and Scaevola gaudichaudii (naupaka kuahiwi).
Historically, B. wiebkei was known on Molokai from Pelekunu and the easternmost section of the island at Halawa. It is still found near Halawa and was recently discovered on privately owned land at Puu Kolekole, just south of its historical range.
The four extant populations of at least 100 total individuals are distributed over a distance of 2.5 by 1 mi (4 by 1.6 km).
The major threats to B. wiebkei include habitat degradation and possible predation by deer and feral goats; competition with alien plants molasses grass and Christmas berry; and fire. Damage or vandalism by humans of those plants found along trails pose problems as well.
Conservation and Recovery
Seeds of B. wiebkei have been collected and propagated by the National Tropical Botanical Garden and Waimea Arboretum.
U. S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
Eastside Federal Complex
911 N. E. 11th Ave.
Portland, Oregon 97232-4181
Pacific Remote Islands Ecological Services Field Office
300 Ala Moana Blvd., Room 3-122
P. O. Box 50088
Honolulu, Hawaii 96850
Telephone: (808) 541-1201
Fax: (808) 541-1216
U. S. Fish and Wildlife Service. 8 October 1992. "Endangered and Threatened Wildlife and Plants; Determination of Endangered or Threatened Status for 16 Plants from the Island of Molokai, Hawaii." Federal Register 57 (196): 46325-46340.