Phyllostegia Hirsuta

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Phyllostegia hirsuta

No Common Name

Status Endangered
Listed October 10, 1996
Family Lamiaceae (Mint)
Description Erect subshrub or vine with stems densely covered with coarse or stiff hairs; corolla is white and usually purple-tinged on the upper lip.
Habitat Steep, shaded slopes in mesic to wet forests dominated by 'ohi'a or a mix-ture of 'ohi'a and uluhe.
Threats Habitat degradation and destruction by feral pigs; potential impacts from military activities; and competition with alien plants.
Range Hawaii

Description

Phyllostegia hirsuta, a member of the mint family (Lamiaceae), is an erect subshrub or vine with stems densely covered with coarse or stiff hairs. The wrinkled leaves are egg-shaped, generally 6.7-12 in (1-30.5 cm) long and 2.9-7 in (7.4-17.8 cm) wide. Both leaf surfaces are moderately covered with long, flat hairs. The upper surface is inconspicuously dotted with glands, while the lower surface is more densely glandulose. The egg-shaped floral bracts are 0.1 to 0.2 in (0.25-0.5 cm) long. The flowers have two lips the upper one is approximately 0.1 in (0.25 cm) long and the lower one is 0.2-0.3 in (0.5-0.75 cm) long. The tubular portion of the flower is slightly curved. The white corolla is usually purple-tinged on the upper lip. The fruit is a nutlet about 0.1 in (0.25 cm) long. This species is distinguished from others in the genus by the texture, hairiness, and size of the leaves and the length of the upper bracts.

James Macrae, botanist on H.M.S. Blonde, collected a plant on Oahu in 1825 that George Bentham described and named P. hirsuta. This species has been maintained in the current treatment of the Hawaiian members of the genus.

Habitat

P. hirsuta is usually found at elevations between 1,970 and 3,610 ft (600.5 and 1,100.3 m) on steep, shaded slopes in mesic to wet forests dominated by 'ohi'a or a mixture of 'ohi'a and uluhe. Associated plant taxa include 'ala'a, kanawao, mamaki, pilo, Hedyotis terminalis (manono), Myrsine lessertiana (kolea lau nui), and native and alien ferns.

Distribution

P. hirsuta was known historically from widespread populations in the Waianae and Koolau Mountains on Oahu. This species ranged from the head of Kukuiula (Pahole) Gulch to North Palawai Gulch in the Waianae Mountains and from Pupukea-Kahuku Trail to Palolo along almost the entire length of the Koolau Mountains. The current distribution of this species in the Waianae Mountains, now restricted to 10 populations in the southern part of its historical range, runs from the ridge between Makaha and Waianae Kai to the south fork of North Palawai Gulch. The current distribution in the Koolau Mountains is six populations scattered over a 6-mi (9.7-km) length of the summit, from Kawainui Gulch in Kawailoa Training Area to South Kaukonahua drainage. About 150-200 individuals remained in these 16 populations in 1997. These populations occur on federal land in Lualualei Naval Reservation and Schofield Barracks Military Reservation; state land, including Mount Kaala National Area Reserve; and private land, including the Nature Conservancy of Hawaii's Honouliuli Preserve and land leased by the Department of Defense for Kawailoa Training Area.

Threats

One threat to P. hirsuta is degradation and destruction by feral pigs.

The noxious shrub Koster's curse and the noxious weed prickly Florida blackberry are both threats to P. hirsuta. Dense stands of strawberry guava threaten this species, as does Christmasberry, which grows in suffocating thickets. The smothering vine huehue haole threatens P. hirsuta, and Lantana, a thicket-forming shrub, is also a menace to this endangered species.

Populations of P. hirsuta that occur on land leased and owned by the U. S. Army face the threat of being damaged through military activity, either by troops in training maneuvers or by the construction, maintenance, and utilization of helicopter landing and drop-off sites. Fire is also a potential threat to this plant, which occurs in dry or mesic habitats where seasonal conditions exist for the easy spread of fire.

Conservation and Recovery

One accession of seeds was made from state lands in the Koolau Mountains during 1997, resulting in more than 70 individuals that flowered in July in the mid-elevation Nike facility in the Waianae Mountains.

The Lyon Arboretum and the National Tropical Botanical Garden have propagated this species, and P. hirsuta seeds are in storage at the National Tropical Botanical Garden.

Contact

U.S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
Eastside Federal Complex
911 N.E. 11th Ave.
Portland, Oregon 97232-4181
(503) 231-6121
http://pacific.fws.gov/

Reference

U.S. Fish and Wildlife Service. 1998. "Recovery Plan for Oahu Plants." U.S. Fish and Wildlife Service, Portland, Oregon. 207 pp., plus appendices.

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Phyllostegia Hirsuta

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