Nohoanu

Geranium multiflorum

Description

The geranium family is represented by herbs, subshrubs, and occasionally tree-like plants. The leaves are alternate or opposite, palmately or pinnately lobed, and dissected or compound. Venation of the leaves is frequently palmate. The flowers are bisexual, actinomorphic or slightly zygomorphic, cymose or in umbels. The fruit is described as a schizocarp and the one to several seeded mericarps split away from the fruit and roll or spiral up on to a central beak.

Nohoanu (Geranium multiflorum ) is a many-branched shrub that reaches a height of 3.3-9.8 ft (9.9-29.4 m). The veined leaves are oval, 1.8-2.8 in (4.5-7 cm) long, and have grayish silky hairs observed generally on the lower surface. The clustered flowers of 25-50 have white petals 0.4-0.6 in (1-15 mm) long, with purple veins or bases. The single seed, contained in each carpel body (the seed-containing section of the fruit), is reddish brown. The carpel body is 0.1 in (2.5 mm) long and topped with an elongated style 0.6-0.8 in (15-20 mm) long that twists to aid dispersal. This species is distinguished from others of the genus by its whitish, regularly symmetrical flowers and by the shape and pattern of teeth on its leaf margins.

Habitat

Geranium multiflorum grows in vegetation communities that range from montane grasslands to wet forests and swamps; it also grows in elevations extending into the subalpine zone (1,600 to 8,800 ft [1,080 to 2,640 m]) and in climates with an annual range of precipitation from as low as 15 in (37.5 cm) to over 100 in (2.5 m). This species occurs on the windward side of East Maui; is found mostly within wet forests; and typically grows in montane grasslands, open sedge swamps, fog-swept lava flows, and occasionally in subalpine shrublands dominated by mamane. Associated species in wet montane forests include 'ohelo, 'ohi'a, pilo, pukiawe, and 'ama'u. Substrates range from lava flows to rich soils.

Distribution

Geranium multiflorum was known from historical occurrences on East Maui at Ukulele, Waieleele, and Waianapanapa. As of 2000, this species is known from Haleakala National Park, Hanawi Natural Area Reserve, Koolau Forest Reserve, and Waikamoi Preserve. There are 11 known populations of this species with a total of no more than 3,000 individuals scattered over a range that covers 6.5 by 3.5 mi (10.4 by 5.6 km).

Threats

The major threats to this species are habitat destruction by feral pigs and goats, and competition with the encroaching alien plant, prickly Florida blackberry.

The recovery of this and most other Hawaiian species depends on how well management practices can be implemented. The habitat of this and other Hawaiian species has undergone extreme alteration because of past and present land management practices, including deliberately introducing alien animals and plants, and agricultural and recreational development. To understand the recovery problems facing this species, it is necessary to understand the long-term causes of habitat destruction.

Conservation and Recovery

The Fish and Wildlife Service published a Recovery Plan for the nohoanu and co-occurring endangered species in 1997. It occurs on conserved natural land in Haleakala National Park, Hanawi Natural Area Reserve, and the Waikamoi Preserve on federal, state, and privately owned land. However, the nohoanu remains threatened by feeding by non-native mammals (especially feral goats and pigs), and by competition and habitat change caused by invasive alien plants (especially the prickly blackberry, Rubus argutus ). Its habitats must be managed to reduce or eliminate these non-native pests. The population of the nohoanu should be monitored, and research undertaken into its biology and habitat needs.

Contact

U.S. Fish and Wildlife Service
Pacific Remote Islands Ecological Services Field Office
P.O. Box 50088
300 Ala Moana Boulevard, Room 3-122
Honolulu, Hawaii 96850-500
Telephone: (808) 541-3441
Fax: (808) 541-3470
E-mail: [email protected]
http://www.rl.fws.gov/pacific

Reference

Culliney, J. 1988. Islands in a Far Sea: Nature and Man in Hawaii. Sierra Club Books, San Francisco.