No Common Name
|Listed||October 29, 1991|
|Description||Sparsely branched with hairy stems, opposite leaves, and lipped, tubular white flowers.|
|Habitat||Slopes and gulches in moist to wetforest.|
|Threats||Alien plant species, low numbers.|
Phyllostegia mollis is a sparsely branched, nonaromatic perennial of the mint family with stems that are densely covered with short hairs. The opposite, oval leaves have rounded teeth and are 4-9.4 in (10-24 cm) long. Lipped and tubular white flowers appear, usually in groups of six, at intervals along the stems. The fruits are fleshy, dark nutlets. This species flowers in the late winter and spring, and its life span is about five years. The species has also been known by the names P. haliakaloe, P. honolulensis, P. parviflora var. honolulensis, and P. parviflora var. mollis.
P. mollis grows on steep slopes and in gulches in moist to wet forest at elevations of 1,500-2,800 ft (450-850 m). Associated plant species include kopiko, papala kepau, raspberry, and various ferns.
Historically, P. mollis was known on the Hawaiian island of Oahu from Mt. Kaala to Honouliuli in the central and southern Waianae Mountains and from Makiki in the Koolau Mountains. It also was known from Molokai and East Maui. This species remains in four populations on Oahu just 2.5 mi (4 km) apart on federal, state, and private land in the Waianae Mountains. These occurrences contained about 120-140 individuals in 1997: one plant grew at Kaluaa Gulch, 45 plants at Palawai, 50-70 at Puu Kumakili, and 19 at Pun Kalena. Only one plant grew at Waiopai Gulch on East Maui.
The major threats to P. mollis are competition from an aggressive non-native plant and its own small population and limited distribution. The habitat of this species is being invaded by Christmas berry, an aggressive tree that forms dense thickets and may also release chemicals that inhibit the growth of other species. With a population of less than 140 plants and a restricted distribution, P. mollis is vulnerable to extinction through unpredictable natural or human-induced events.
Conservation and Recovery
P. mollis is being successfully propagated at the Lyon Arboretum and the National Tropical Botanical Garden. The Palawai population is located within the boundaries of a fenced exclosure that the Nature Conservancy of Hawaii constructed in 1998. Taxonomic research is needed to examine the genetic differences between the Oahu and Maui populations of this species; pending the results of such investigations, the Maui population may be separated into its own species.
U. S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
Eastside Federal Complex
911 N. E. 11th Ave.
Portland, Oregon 97232-4181
Telephone: (503) 231-6121
U. S. Fish and Wildlife Service
Pacific Remote Islands Ecological Services Field Office
300 Ala Moana Blvd., Room 3-122
P.O. Box 50088
Honolulu, Hawaii 96850-5000
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. Cooperation National Park Resources Study Unit, University of Hawaii Press, Honolulu.
Stone, C. P., and J. M. Scott, eds. 1985. Hawai 'i'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 Hawai 'i. University of Hawaii Press and Bishop Museum Press, Honolulu.