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Conserving and restoring
America's native plants |
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CPC National Collection Plant Profile
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Marsilea villosa
| Family: |
Pteridophyta (Ferns) |
| Common Names: |
'ihi La'au, 'ihi'ihi, 'Ihi'ihilauakea, villous water-fern |
| Author: |
Kaulfuss |
| Growth
Habit: |
Fern |
| CPC
Number: |
2808 |
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| Primary
custodian for this plant in the CPC National Collection of Endangered
Plants is: |
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| David Orr contributed to this Plant Profile. |
Marsilea villosa
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Marsilea villosa is a fern found only in the Hawaiian Islands, restricted to areas with irregular flooding regimes. Currently, it is known from 3 populations of O`ahu and 2 population on Moloka`i. Many of the historic populations on O`ahu were destroyed by drainage of ponding areas, habitat degradation, competition from alien plants, off road vehicles and development.
Marsilea villosa resembles a four-leaf clover, with four leaflets borne at the end of a leaf stalk. The plant occurs either in scattered clumps or as a dense interwoven mat, depending on the competition with other species for limited habitat resources. Marsilea villosa requires periodic flooding for spore release and fertilization, then a decrease in water levels for the young plants to establish, and finally dry soil for the plants to mature.
| Distribution
& Occurrence |
|
State Range
Habitat
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Restricted to areas with irregular flooding regimes and low elevations. Grows in small shallow depressions in silty clay or sand common in dry areas of most islands where winter rains create seasonal pools (USFWS 1996). |
Distribution
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O`ahu- Koko Head, Lualualei, and Makapuu
Moloka`i- Kamaka`ipo and Moki`o
(USFWS 1996) |
Number Left
| |
O`ahu- Lualualei- 1 population
O`ahu- Makapu`u- 1 population
O`ahu- Koko Head- 1 population
Moloka`i- Kamaka`ipo-1 population
Moloka`i- Moki`o- 1 population
Approximately 4000 plants total
(USFWS 1996, 2001) |
State/Area
Protection
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State/Area |
Rank |
Status |
Date |
|
| |
Hawaii |
S1 |
LE |
4/11/2002 |
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| Conservation,
Ecology & Research |
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Ecological
Relationships
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Sexual reproduction of Marsilea villosa is initiated through the production of a hard sporocarp borne on the rhizome leaf pair node. The sporocarp will mature only if the soil dries below threshold levels for leaf growth. The sporocarp remains in the soil for an extended period of time and must be scarified before it will open. It is not known how the sporocarp is scarified in Marsilea villosa, but bacterial action is thought to erode the wall of the sporocarp to the point that water can be absorbed and force the sporocarp to open.
Standing water is necessary for the sporocarp to open and release the male and female spores. Standing water also is needed for the sperm to swim to the female spore containing the egg. For Marsilea villosa, flooding and sexual reproduction may occur as infrequently as once every ten or more years, due to the infrequency of sufficiently heavy rains in the lowland areas of Hawai`i. The method of dispersal of Marsilea villosa sporocarps is unknown, although in other species, water birds have been known to disperse either internally or externally (USFWS 1996). |
Threats
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Encroachment of alien vegetation.
Habitat degradation by off-road vehicles.
Fire.
Development.
Small population size.
Trampling by humans and animals.
Browsing by feral animals.
(USFWS 1996, 2001) |
Current Research Summary
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Reproduction biology studies.
Propagation-rhizomes and sporocarps.
(USFWS 1996) |
Current Management Summary
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O`ahu
• Lualualei- removal of cattle and monitoring
• Koko Head- barrier created around population. Removal of alien plant species. Monitoring.
Moloka`i
• Kamaka`ipo- Adjustment of condominium and golf course plans by private developers.
(USFWS 1996) |
Research Management Needs
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Exclosures or barriers around the rest of the populations.
Decrease human and animal disturbance.
Control alien plant species.
Fire protection.
(USFWS 1996) |
Ex Situ Needs
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Ex situ establishment in gardens.
Seed banking.
Physiological studies.
Genetic studies.
Propagation- germplasm preservation, increase numbers of individuals.
(USFWS 1996) |
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| Books (Single Authors)
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| Hillebrand, W. 1888. Flora of the Hawaiian Islands: a description of their phanerogams and vascular cryptogams. Carl Winter, Heidelberg, Germany; Williams & Norgate, London; B. Westermann & Co., New York. 673p. |
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| Wagner, W.L.; Bruegmann, M.M.; Herbst, D.R; Lau, J.Q.C. 1999. Hawaiian Vascular Plants at Risk: 1999. Honolulu, HI: Bishop Museum Press Honolulu. |
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| Books (Sections)
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| Kartesz, J.T. 1999. A synonymized checklist of the vascular flora of the U.S., Canada, and Greenland. In: Kartesz, J.T.; Meacham, C.A., editors. Synthesis of the North American Flora, Version 1.0. North Carolina Botanical Garden. Chapel Hill, NC. |
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| Electronic Sources
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| (2002). Hawaiian Native Plant Genera. ¬ Gerald D. Carr, University of Hawaii Botany Department. http://www.botany.hawaii.edu/faculty/carr/natives.htm. Accessed: 2002. |
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| Journal Articles
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| Forbes, C.N. 1920. Notes on Marsilea villosa Kaulf. Occas. Pap. Bernice P. Bishop Mus. 8, 5: 3-5. |
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| Garnett, W. 1990. Plants in the National Collection of the Center for Plant Conservation growing at Waimea Arboretum Botanical Garden. Notes from Waimea Arboretum & Botanical Garden. 17, 2: 4-16. |
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| USFWS. 1991. Listing Proposals. Endangered Species Technical Bulletin. 16, 3: 4-5. |
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| USFWS. 1991. Proposed endangered status for a Hawaiian plant, Marsilea villosa ('ihi'ihi). Federal Register. 1991, 56: 6350-6353. |
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| USFWS. 1992. Determination of endangered status for Marsilea villosa ('ihi'ihi). Federal Register. 57, 120: 27863-27867. |
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| USFWS. 2000. Determinations of Whether Designation of Critical Habitat Is Prudent for 20 Plant Species and the Proposed Designations of Critical Habitat for 32 Plant Species From the Island of Molokai, HI. Federal Register. 65, 251: 83158-83216. |
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| USFWS. 2002. Designations of Critical Habitat for Plant Species From the Island of Oahu, Hawaii. Federal Register. 67, 102: 37108-37156. |
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| USFWS. 2002. Revised Determinations of Prudency and Proposed Designations of Critical Habitat for Plant Species From the Island of Molokai, Hawaii. Federal Register. 67, 66: 16492-16579. |
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| Wester, L.W. 1994. Weed management and habitat protection of rare species: A case study of the Endemic Hawaiian Fern, Marsilea villosa. Biological Conservation. 68, 1: 1-9. |
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| Newspaper Articles
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| Miller, Ken. 1992 June 23, 1992. Two more Hawaii plants given federal protection. Honolulu Star Bulletin; Honolulu, HI. 1 pp. |
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| TenBruggencate, Jan. 1997 January 6, 1997. Rare fern likes floods, dry seasons. The Honolulu Advertiser; |
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| Reports
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| USFWS. 1996. Marsilea villosa Recovery Plan. Portland, Oregon: U.S. Fish and Wildlife Service. p.55. |
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| USFWS. 2001. U.S. Fish and Wildlife Service Species List. March 30, 2000. Honolulu: Unpublished. U.S. Fish and Wildlife Service. p.19. |
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