Kuahiwi Laukahi

Plantago princeps

Description

Plantago princeps (also known by the Hawaiian name kuahiwi laukahi) is a small shrub or robust perennial herb of the plantain family. Its erect or ascending stems are hollow, about 1-100 in (2.5-254 cm) long, and often branched with young internodes that are more or less woolly with reddish-brown hairs. The oblong to elliptic, thick, leathery leaves are 2.4-12 in (6.1-30.5 cm) long, up to 2 in (5.1 cm) wide, and are tufted near the ends of stems. Each leaf also has smooth or minutely toothed margins, a pointed tip, and primary veins that converge at the base. Numerous stalkless flowers are densely arranged in a cluster 4.3-11 in (10.9-27.9 cm) long, with each cluster on a stalk 4-20 in (10.2-50.8 cm) in length. Each flower spreads at an angle of nearly 90° to the axis of the stalk or grows upright. The sepals are somewhat distinct and elliptic in shape. The fruits are capsules that contain three or four tiny black seeds, and the surface of each seed is apparently covered with a sticky membrane. This species differs from other native members of the genus in Hawaii by its large branched stems, flowers at nearly right angles to the axis of the flower cluster, and fruits that break open at a point two-thirds from the base.

Louis Charles Adelbert von Chamisso and D.F.L. Schlectendal described the species P. princeps in 1826. Several varieties and forms of P. princeps have also been described. The currently accepted classification places P. queleniana and P. fauriei in synonymy with P. princeps and recognizes only four varieties: anomala, laxifolia, longibracteata, and princeps.

Habitat

P. princeps is typically found on steep slopes, rock walls, or at bases of waterfalls from 1,580 to 3,600 ft (482 to 1,097 m) in elevation. Associated plant species include 'a'ali'i, kopiko, 'ohi'a, uluhe, and Dubautia plantaginea.

Distribution

P. princeps was found historically on Kauai, Oahu, Molokai, Maui, and the island of Hawaii. Although this variety is no longer extant on the Big Island, approximately 640-1,750 individuals in 29 populations still remained statewide in 1997.

Threats

The primary threats to P. princeps are habitat degradation by pigs and goats and competition with various alien plant species.

P. princeps is not known to be unpalatable to cattle, deer, and goats; as such, predation is a probable threat to this plant at sites where these animals have been reported.

Two of the populations of P. princeps var. princeps on Oahu have been damaged by Christmasberry. Christmasberry is spreading on East Maui in Iao Valley and on the south slope of Haleakala Volcano, proving in both locations to be one of the primary alien plant threats to the populations of P. princeps var. laxiflora that exist there.

Strawberry guava poses an immediate threat to one population of P. princeps var. princeps on Oahu. This aggressive alien plant is also beginning to invade the habitat of one population of P. princeps var. laxiflora on West Maui and at least one population of this variety on East Maui.

In the Waianae Mountains of Oahu, one population of P. princeps var. princeps is immediately threatened by molasses grass. At least one population of P. princeps var. laxiflora is being harmed on Molokai by molasses grass. Koster's curse poses a serious threat to two populations of P. princeps var. longibracteata in the Koolau Mountains of Oahu.

Conservation and Recovery

The U.S. Army Garrison's Five-Year Ecosystem Management Plans for all of its training areas in the State of Hawaii to protect endangered species, prevent range fires, and minimize soil erosion are expected to enhance conservation of the P. princeps plants found on the Makua Military Reservation.

The long-range management plan for Honouliuli Preserve includes actions for alien plant management, ungulate control, fire control, rare species recovery, and native habitat restoration. These actions are expected to benefit P. princeps in the preserve. In addition, several miles of pig-proof fencing was constructed in Palawai Gulch in 1997. It encloses approximately 90 acres (36.4 hectares) of rare plant habitat and may include the P. princeps population.

The State Division of Forestry and Wildlife hopes to propagate plants at its Pahole Plant Nursery when seeds from these plants are available. Two plants of an unspecified variety of P. princeps are in cultivation at the National Tropical Botanical Garden.

Attempts at micropropagation of P. princeps var. anomala at Lyon Arboretum have been unsuccessful.

Contacts

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
http://pacific.fws.gov/

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

Reference

U. S. Fish and Wildlife Service. 10 November 1994. "Endangered Status for 12 Plants from the Hawaiian Islands." Federal Register 59 (217): 56333-56351.