|Listed||October 8, 1992|
|Description||Bellflower with oval leaves, fragrant flowers clustered in groups of three to eight.|
|Habitat||Rock crevices on inaccessible steep sea cliffs.|
|Threats||Habitat disturbance; predation by wild, feral, or domestic animals.|
Pua'ala, Brighamia rockii, is a bellflower that grows as an unbranched plant 3.3-16 ft (1-5 m) tall with a thickened succulent stem that tapers from the base. The fleshy, oval leaves are widest at their tips and are arranged in a rosette at the top of the plant. The leaves measure 2.4-8.7 in (6-22 cm) long and 2-6 in (5-15 cm) wide. The fragrant flowers are clustered in groups of three to eight on the leaf axils. Each flower cluster is on a stalk 1.4-3 in (3.5-7.5 cm) long, and individual flowers connect to a stalk 0.2-0.4 in (6-12 mm) long. The 10-ribbed hypanthium is topped by five calyx lobes 0.2-0.5 in (6-13 mm) long.
The petals are fused into a green to yellowish-green tube that flares into five white, elliptic lobes. The capsulelike fruit is 0.5-0.8 in (1.3-2 cm) long and contains numerous seeds. This species is an endemic Hawaiian genus that differs from other Brighamia species by the color of its petals, the longer calyx lobes, and the shorter flower stalks.
B. rockii grows in rock crevices on inaccessible steep sea cliffs along East Molokai's northern coastline in coastal dry to mesic forests or shrublands at an elevation of sea level to 1,540 ft (470 m). Associated species include Canthium odoratum (alahe'e), Osteomeles anthyllidifolia ('ulei), and Scaevola (nanpaka).
Endemic to the Hawaiian Islands, B. rockii once ranged along the northern coast of East Molokai from Kalaupapa to Halawa and may possibly have grown on Lanai and Maui. Its range is now reduced to scattered populations on steep, inaccessible sea cliffs along East Molokai's northern coastline from Anapuhi Beach to Wailau Valley on private land, and on the relatively inaccessible state-owned sea stack of Huelo, east of Anapuhi Beach. The five known populations of B. rockii that extend over this 6.5-mi (10.5-km) long stretch total fewer than 200 individuals.
Habitat damage and possible predation by deer and goats pose serious threats to B. rockii. Competition with alien plants is also a threat. Although there is no evidence that rats feed on the fruits, these rodents are also a potential threat, as evidenced by their predation on related Hawaiian genera. Recent observations suggest that low reproductive rates in wild populations could be due to a combination of factors including low production of pollen, low establishment of seedlings, and a lack of pollinators.
Conservation and Recovery
Hand pollinations of B. rockii have been conducted, and seeds have been collected and propagated by the National Tropical Botanical Garden. No additional species-specific conservation efforts have been undertaken.
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
U. S. Fish and Wildlife Service. 8 October 1992. "De-termination of Endangered or Threatened Status for 16 Plants from the Island of Molokai, Hawaii." Federal Register 57 (196): 46325-46340.