Phyllostegia velutina

No Common Name

Description

Phyllostegia velutina, of the mint family, is a climbing vine with dense, backward-pointing hairs on the leaves and square stems. The hairs are silky on the opposite, narrow, toothed leaves, which are 3.6-6.9 in (9.1-17.5 cm) long and 1-2 in (2.5-5 cm) wide. Six to ten white flowers are borne in an unbranched inflorescence with conspicuous leaflike bracts. The green bell-shaped calyx is 0.4 in (1 cm) long, upper lip 0.2-0.3 in (0.5-0.75 cm) long, and lower lip 0.1-0.2 in (0.25-0.5 cm) long. Fruits are divided into four nutlets about 0.1-0.2 in (0.25-0.5 cm) long. This species is distinguished from others in this genus by its silky hairs, lack of a main stalk to the flower clusters, and calyx teeth that are narrow and sharply pointed. Based on a specimen collected on Mauna Kea by the U. S. Exploring Expedition in 1840, a new variety of P. macrophylla var. velutina was described, named for its velvety leaves and stems. Harold St. John determined that this entity was sufficiently different to constitute a separate species, P. velutina, which has been maintained in the current treatment of the genus.

Habitat

P. velutina typically grows in 'ohi'a-and koa-dominated montane mesic and wet forests at elevations between 4,900 and 6,000 ft (1,493.5 and 1,828.8 m). Associated taxa include hapu'us, Cheirodendron trigynum ('olapa), 'ohelo, pilo, Dryopteris wallichiana, akala, mamaki, ho'i'o, Myrsine sp. (kolea), and Ilex anomala (kawa'u).

Distribution

Historically, P. velutina occurred on the island of Hawaii on the southern slopes of Hualalai and the eastern, western, and southern slopes of Mauna Loa. Three extant populations are known to occur at Puu Waawaa on a state-owned wildlife sanctuary, in Honuaula Forest Reserve on state-owned land, and at Kulani/Keauhou on a state-owned correctional facility and adjacent privately owned land. Approximately 30-55 plants are known from these three populations. A fourth population has been reported from the general area of Waiea Tract in South Kona, but the exact location and current status of this population are unknown.

Threats

Threats to P. velutina are habitat damage by cattle, feral pigs and sheep; prison facility expansion, road clearing, and logging; competition from alien plants, such as kikuyu grass, yellow Himalayan raspberry, Vasey grass, and fountain grass; fire; habitat change due to volcanic activity; and a risk of extinction from naturally occurring events and/or reduced reproductive vigor due to the small number of existing populations and individuals.

Conservation and Recovery

As of May 1998, the Volcano Rare Plant Facility had 282 plants; the National Tropical Botanical Garden had two plants and 251 seeds. The Puu Waawaa population has been fenced to exclude ungulates. Inmates from the Kulani Correctional Facility, through the Olaa-Kilauea Partnership, are fencing individual plants for short-term protection while plans are being implemented for larger fenced areas. Preliminary efforts are being made to search for natural enemies of the yellow Himalayan raspberry.

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. "Big Island II: Addendum to the Recovery Plan for the Big Island Plant Cluster." U.S. Fish and Wildlife Service, Portland, Oregon. 80 pp., plus appendices.