Fosberg's Love Grass

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Fosberg's Love Grass

Eragrostis fosbergii

ListedOctober 10, 1996
FamilyPoaceae (Grass)
DescriptionGrass with abruptly bent woody base and leathery leaf blades; stiffly ascending flowering stalk and long hairs on the margins of the glumes.
HabitatRidge crests or moderate slopes in native or alien forests.
ThreatsDegradation of habitat by feral pigs and goats; competition with alien plants.


Eragrostis fosbergii, a perennial grass (family Poaceae), has stout, tufted culms (stems) 24-40 in (60.9-101.6 cm) long that usually arise from an abruptly bent woody base. The leathery leaf blades, 16-24 in (40.6-60.9 cm) long and 0.2-0.4 in (5.0-10.1 mm) wide, are flat, although they curl inward towards the apex. The small flowers occur in complex clusters that are somewhat open, pyramidal, and 8-16 in (20.3-40.6 cm) long. The pale to dark green spikelets (ultimate flower clusters) are about 0.2 in (5.0 mm) long and generally contain three to five flowers. The slender glumes, small bracts at the base of the spikelet, have margins fringed with long hairs. The lemmas (inner bracts that subtend the flowers) have loosely overlapping margins occasionally fringed with hairs. The fruit is a grain. This species is distinguished from others in the genus by its stiffly ascending flowering stalk and the long hairs on the margins of the glumes and occasionally on the margins of the lemma.

In 1933, F. Raymond Fosberg collected a plant in the Waianae Mountains that Leo D. Whitney named E. fosbergii in 1937. This species is maintained in the most recent treatment of Hawaiian members of this genus.


E. fosbergii typically grows on ridge crests or moderate slopes in native or alien forests at an elevation of between 2,360 and 2,720 ft (719 and 829 m). Associated plant taxa include Christmas-berry, koa, 'ohi'a, Psydrax odoratum (alahe'e), Dodonaea viscosa ('a'ali'i), and E. grandis (kawelu).


Historically, E. fosbergii was known on Oahu only from the Waianae Mountains, from the slopes of Mount Kaala, and in Waianae Kai and its associated ridges. This species was thought to be extinct until rediscovered by Joel Lau of the Nature Conservancy of Hawaii in 1991. Only six individuals in four populations remained in 1997 in Waianae Kai on land owned by the state and the City and County of Honolulu.


Major threats to E. fosbergii include degradation of habitat by feral pigs and goats; competition with alien plants such as Christmasberry, silk oak, and strawberry guava; and trampling by hikers. This species also is threatened by the risk of extinction from random natural events and reduced reproductive vigor due to the small number of remaining populations and individuals.

E. fosbergii is directly threatened by feral goat trampling of plants and seedlings, as well as by goat-induced substrate erosion. E. fosbergii is not known to be unpalatable to goats and grows in areas where they have been reported; direct predation is therefore a possible threat.

Dense stands of strawberry guava threaten E. fosbergii. Christmasberry grows in dense thickets that threaten this species, and silk oak also poses a threat to this plant.

Overcollection for scientific or horticultural purposes and excessive visits by individuals interested in seeing rare plants in their natural settings could seriously damage E. fosbergii, whose populations are close to trails and roads, thus giving easy access to potential collectors.

E. fosbergii has populations in recreational areas, near trails, and close to roads, making it very vulnerable to human disturbance.

Conservation and Recovery

Staff from Division of Forestry and Wildlife and the Nature Conservancy of Hawaii conducted surveys during 1996-1997 in the Waianae Kai area, but located no individuals of this plant. It is difficult to identify in the field because flowers are needed to confirm its identity.


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.