No Common Name
|Listed||October 29, 1991|
|Description||Shrub with heart-shaped leaves and single, drooping flowers with green petals, often tipped with reddishbrown.|
|Habitat||Steep slopes in dry to moist forest.|
|Threats||Invasive alien plant species, fire, cattle.|
Abutilon sandwicense is a shrub of the mallow family (Malvaceae). It is covered with short glandular hairs and grows to 10 ft (3 m) in height. The shrub's heart-shaped leaves are light green and 3-9 in (7.6-22.9 cm) long. A single pendulous flower grows from the leaf axil, the point between the leaf and the stem. The flowers have pale, greenish-yellow, hairy, glandular sepals, as well as bright green petals (often tipped in reddish-brown) up to 2 in (5.1 cm) long. A greenish-yellow staminal column with about 350 stamens near its tip protrudes from the flower. The fruit, a capsule up to 1 in (2.5 cm) long, breaks into eight to ten parts, each enclosing three or more seeds. The brown seeds are slightly hairy and 0.1 in (2.5 mm) long. This species is distinguished from others in the genus by the green or reddish-brown tipped petals that extend beyond the sepals.
A. sandwicense has been observed flowering in winter and spring. Most plants have flowered by summer, and the fruits have usually dried up by fall. Fruit capsules develop within six weeks. Although seedlings are often initially abundant, few plants appear to survive to maturity for unknown reasons. The species has also been known by the name Abortopetalum sandwicense.
A. sandwicense typically grows on steep slopes or gulches in dry to mesic lowland forest at an elevation of 1,000-2,000 ft (304.8-609.6 m). Associated species include Diospyros ssp. (lama), Sapindus oahuensis (aulu), Pipturus albidus (mamaki), Elaeocarpus bifidus (kalia), Nestegis sandwicensis (olopua), and Psyrdax odoratum (alahee).
A. sandwicense had historical occurrences along nearly the entire length of the Waianae Mountains, from Makaleha Valley to Nanakuli Valley. This species is now known from Makaleha Valley east to Palikea Gulch, south to Nanakuli Valley, and at Makaha-Waianae Kai Ridge on federal, state, city/ county, and privately owned land. The 12 known populations, found in an area of about 5 by 10 mi (8 by 16.1 km), contained about 280-290 individuals in 1994.
The major threats to A. sandwicense are competition from alien plants (Christmasberry, Koster's curse, molasses grass, and huehue haole); fire; and trampling by goats, pigs, and cattle. Cultivated plants of A. sandwicense are also affected by the black twig borer.
Conservation and Recovery
The Nature Conservancy is monitoring and controlling alien weeds around one population of A. sandwicense in Honouliuli Preserve at Huliwai Gulch. The 11 plants in this population appear to be healthy, but they are threatened by Passiflora suberosa and human activity on an adjacent trail. A. sandwicense has been outplanted by Division of Forestry and Wildlife at Pahole Natural Area Reserve. It has also been successfully propagated at the National Tropical Botanical Garden and the Waimea Arboretum.
U. S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
Eastside Federal Complex
911 N.E. 11th Avenue
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.