Ha'iwale (Cyrtandra subumbellata)
|Listed||October 10, 1996|
|Family||Gesneriaceae (African violet)|
|Description||Shrub with papery textured leaves and five to 15 densely arranged white flowers.|
|Habitat||Moist, forested slopes or gulch bottoms dominated by 'ohi'a or a mixture of 'ohi'a and uluhe.|
|Threats||Competition from alien plants, potential predation by rats, and potential fire.|
Cyrtandra subumbellata is a shrub of the African violet family that grows to a height of 6.6-10 ft (2.0-3.0 m). The papery leaves are almost circular to egg-shaped, 4.7-15.4 in (11.9-39.1 cm) long, and 1.2-7.5 in (3.0-19.1 cm) wide. The upper leaf surface is wrinkled, whereas the lower surface has conspicuously raised netlike veins and is moderately covered with white glands. Five to 15 white flowers are densely arranged on an inverse umbrella-shaped flowering stalk that arises from the leaf axil. The main flower stalk is 0.1-0.3 in (2.0-7.6 mm) long. The style is approximately 0.4 in (1.0 cm) long. The round, white berries are 0.4-0.6 in (1.0-1.5 cm) long. This species is distinguished from others in the genus by the number and arrangement of the flowers, the lengths of the style and main flower stalks, and the texture of the leaves. C. subumbellata has been observed in fruit in September.
Wilhelm Hillebrand collected a specimen on Oahu that he named Cyrtandra gracilis var. subumbellata in 1888. Harold St. John and W. B. Storey elevated the variety in 1950 to full species status. The authors of the current treatment of the family concur with this designation, and they do not recognize the variety St. John named in 1966. The specific cific epithet refers to the umbrellalike flowering stalk.
C. subumbellata typically grows at elevations between 1,500 and 2,200 ft (457.2 and 670.6 m) on moist, forested slopes or gulch bottoms dominated by 'ohi'a or a mixture of 'ohi'a and uluhe. Associated plant taxa include 'uki, Adiantum raddiantum, 'akole, kanawao, and Thelypteris sp.
C. subumbellata was historically known from six scattered populations in the central Koolau Mountains on the island of Oahu, but the species is now known from just three populations. These occur at Schofield-Waikane Trail and Pu'u Ohulehule on private and state land and Kaukonahua drainage on federal land within Schofield Barracks Military Reservation. The total number of extant plants was estimated to be less than 50 in 1997.
The major threats to C. subumbellata are competition with the alien plant Koster's curse, potential impact from military activities, potential predation by rats and slugs. Additionally they are at risk of extinction from naturally occurring events or reduced reproductive vigor due to the small number of remaining populations and individuals.
Populations of C. subumbellata 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. Unintentionally ignited fires from ordnance training practices on military reservations pose a potential threat to this taxon.
Conservation and Recovery
The Lyon Arboretum and the National Tropical Botanical Garden are propagating C. subumbellata.
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. 1998. "Recovery Plan for Oahu Plants." U.S. Fish and Wildlife Service, Portland.