|Listed||October 29, 1991|
|Description||Branched, hairy shrub with opposite leaves and a slender flower spike at the stem ends.|
|Habitat||Gulches, steep slopes, and cliff faces in open dry forest.|
|Threats||Feral pigs, goats, and cattle; alien plant species.|
Nototrichium humile (also called kulu'i) is a branched, upright to trailing shrub of the amaranth family with stems up to 5 ft (1.5 m) long. The stems and leaves are covered with short hairs. The opposite, oblong leaves are 1.2-3.5 in (3-8.9 cm) long. Stalkless flowers appear on a slender spike 1.2-5.5 in (3-14 cm) long at the stem ends. Plants have been observed flowering after heavy rain, but flowering is generally heaviest in the spring and summer. Fruits mature a few weeks after flowering. The species has also been known as Psilotrichum humile.
N. humile is found on and at the base of rock cliffs and talus slopes in areas that do not receive full sun all day. It typically grows at an elevation of 200-2,300 ft (61-701 m) on cliff faces, gulches, or steep slopes in remnants of open dry forests often dominated by aulu or lama. Associated species include alahee, 'ohia' ha, Reynoldsia sandwicensis (ohe), Pleomele sp. (halapepe), Myrsine lanaiensis (kolea), and papala kepau.
N. humile had historical occurrences on Oahu (along the entire length of the Waianae Mountains) and on East Maui. The species is still extant on Oahu from Kaluakaulla Gulch, along Makua-Keaau Ridge to Makaha-Waianae Kal Ridge and Nanakuli, where it occurs on federal, state and private lands. It is also extant in Maui's Lualailua Hills on private land. Fourteen of the 15 known populations grow within an area of about 3 by 11 mi (4.8 by 17.7 km) in the Waianae Mountains; the other population is the poorly documented Maui occur-rence at Lualualei. The combined total of all the occurrences was estimated at 1,489-1,519 individuals in 1997. The six populations at Lualualei—Mikilua and Pahoa subdistricts, Palehua, Kealia, Kipuna Gulch, and Waianae Kai—all numbered fewer than 12 individuals.
On both Oahu and East Maui, the major threats to N. humile are habitat degradation by feral goats, pigs, and cattle; military activities; competition from the alien plants Christmas berry, koa haole, molasses grass, and strawberry guava; and fire.
Conservation and Recovery
One N. humile individual has been outplanted by the Nature Conservancy of Hawaii in a fenced enclosure in Honolulu Preserve; as of November 1997, this plant was in good condition. There are two collections at the Pahole mid-elevation Nike site. Approximately ten of the wild individuals are within the boundaries of a large fenced enclosure at Kahanahaiki Gulch. General weeding efforts within this area may benefit the species. The National Tropical Botanical Garden has collected N. humile seed, and the species is being propagated at the Waimea Arboretum. The populations that have only a few remaining individuals should be immediately fenced, weeded, and otherwise protected. Once these areas have been enclosed, commitments should be developed for their long-term steward-ship and conservation. A coordinated fire protection plan for endangered plant species on state forest reserves (Waianae Kal) and federal lands (Lualualei Naval Reservation) needs to be developed and implemented.
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
Cuddihy, L. W., and C. P. Stone. 1990. Alteration of Native Hawaiian Vegetation: Effects of Humans, Their Activities, and Introductions.Cooperative National Park Resources Study Unit, University of Hawaii Press, Honolulu.
Stone, C. P., and J. M. Scott, eds. 1985. Hawaii's Terrestrial Ecosystems: Preservation and Management. Cooperative National Park Resources Study Unit, University of Hawaii Press, Honolulu.
Wagner, W. L., D. R. Herbst, and S. H. Sohmer. 1990. Manual of the Flowering Plants of Hawaii. University of Hawaii Press and Bishop Museum Press, Honolulu.