National Collection of Imperiled Plants

CPC National Collection Plant Profile

Photographer:

Dieter Wilken

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CPC National Collection Plant Profile

Helianthemum greenei

Family:	Cistaceae
Common Name:	island rush-rose
Author:	B.L. Robins.
Growth Habit:	Subshrub, Shrub, Forb/herb
CPC Number:	2190

Distribution
Protection
Conservation
References

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Photographer: Dieter Wilken
dwilken[at]sbbg.org

Helianthemum greenei is Not Sponsored

Primary custodian for this plant in the CPC National Collection of Endangered Plants is:

Santa Barbara Botanic Garden

Dieter Wilken, Ph.D. contributed to this Plant Profile.

Helianthemum greenei

Flowers have 5 bright yellow petals and are about 2 cm in diameter. One-year-old plants with 1-5 flowers may be only 10-15 cm tall. However, mature plants may reach 0.5 m in height, producing up to 100 flowers on multiple branches, and may live for up to 10 years. The minute, black, globose seeds, less than 0.5 mm in diameter, have exceedingly thick coats and show low rates of germination unless abraded and/or heated. Most occurrences are each composed of 1 to 7 widely scattered plants. However, a few large populations with high densities have been found in burned chaparral, with most plants persisting for about 4-5 years.

Distribution & Occurrence

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State Range

California

Habitat

Open sites on rocky to gravelly soils of bluffs, slopes, and ridges, often in chaparral or mixed oak-pine woodland. Common associates include Pinus muricata and species of Arctostaphylos, Ceanothus, Eriogonum, and Quercus.

Distribution

Santa Catalina, Santa Cruz, and Santa Rosa islands.

Number Left

At least 14 occurrences have been documented, including one each on Santa Catalina and Santa Rosa islands respectively. The remaining 12 are known from widely scattered localities on Santa Cruz Island. Most occurrences are composed of less than 10 plants each. However, one area on Santa Cruz Island, which was burned in 1994, supported several 1000 individuals for 4-5 years, followed by a decline to a few hundred individuals in 2000.

Protection

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Global Rank:	G2	6/18/1997	Guide to Global Ranks
Federal Status:	LT	7/31/1997	Guide to Federal Status
Recovery Plan:	Yes	9/26/2000

State/Area Protection

	State/Area	Rank	Status	Date
	California	S2.2	5

Conservation, Ecology & Research

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Ecological Relationships

� Island rush-rose is self-compatible and partly self-pollinating (McEachern et al., 1997). However, insect visitation by small bees and flies results in complete seed set in most flowers, which each produce 10-12 seeds.
� Seed germination is enhanced by scarification and/or heat (Wilken pers. obs.).
� Highest densities of plants were found in open sites among completely burned shrubs after a fire on Santa Cruz Island (Wilken pers. obs.).
� Plants can be found on a diversity of substrates, ranging from fine-grained shales to rocky volcanic soils, and occasionally alluvial deposits in ephemeral stream channels.

Threats

As listed in the recovery plan for thirteen plants from the northern channel islands (USFWS 2000):
� Loss of small populations as a result of feral pig activities.
� Competition from noxious weeds.
� Erosion at sites near established roads.

Current Research Summary

� Demography is being studied on Santa Cruz island by the Santa Barbara Botanic Garden. Populations on Santa Catalina and Santa Rosa islands are being monitored by the Catalina Island Conservancy and the National Park Service, respectively.
� Seed biology is being studied by Carol Baskin at the University of Kentucky.

Current Management Summary

The population on Santa Catalina Island is managed by the Catalina Island Conservancy and is protected from disturbance by feral goats and pigs. The population on Santa Rosa Island is managed by the National Park Service and is protected from grazing by feral deer and elk. Populations on Santa Cruz Island occur on lands owned and managed partly by The Nature Conservancy and partly by the National Park Service. The Nature Conservancy and the National Park Service are working collaboratively to develop a plan for weed control and removal of feral pigs, but no short-term measures have been taken to protect vulnerable populations.

Research Management Needs

� Genetic analyses within and among populations, including the natural seed bank.
� Studies of ecological factors that influence establishment and survival, including competitive effects of native vegetation and potential mycorrhizal relationships.

Ex Situ Needs

Seed collections representing the entire geographic distribution.

References

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Books (Single Authors)

Skinner, M.W.; Pavlik, B.M. 1997. Inventory of rare and endangered vascular plants of California: Electronic Inventory Update of 1994, 5th edition. Sacramento: California Native Plant Society.

Books (Sections)

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.

Books (Edited Volumes)

James C. Hickman, Editor. 1993 The Jepson manual: Higher plants of California. Berkeley: University of California Press. 1400p.

Electronic Sources

(2002). New York Botanical Garden--The Virtual Herbarium. [Searchable Web site] New York Botanical Garden. Fordham Road Bronx, New York. http://scisun.nybg.org:8890/searchdb/owa/wwwspecimen.searchform. Accessed: 2002.

CatalinaConservancy. (2002). Island Ecology: Plants of Catalina Island. Catalina Island Conservancy. http://www.catalinaconservancy.org/ecology/plants/species1.asp. Accessed: 2002.

USFWS. (2002). Threatened & Endangered Plants Within Ventura Field and Wildlife Office Area of Responsibility. U.S. Fish and Wildlife Service, Ventura Fish and Wildlife Office. http://ventura.fws.gov/plant.html. Accessed: 2002.

Journal Articles

Thorne, R.F. 1967. A flora of Santa Catalina Island, California. Aliso. 6, 3: 1-77.

Thorne, R.F. 1969. A supplement to the floras of Santa Catalina and San Clemente Islands, Los Angeles County, California. Aliso. 7, 1: 73-83.

USFWS. 1995. Proposed rule for 16 plant taxa from the northern Channel Islands, California. Federal Register. 60, 142: 37993-38010.

USFWS. 1997. Final rule for 13 plant taxa from the northern Channel Islands, California. Federal Register. 62, 147: 40954-40974.

USFWS. 1997. Notice of Reopening of Comment Period on Proposed Endangered Status for Sixteen Plants from the Northern Channel Islands of California. Federal Register. 62, 14: 3263.

Reports

McKeachern, K.; Wilken, D.; Chess, K. 1997. Inventory and monitoring of California islands candidate plant taxa. U.S. Geological Survey, Biological Resources Division. p.46.

USFWS. 2000. Thirteen plant taxa from the northern Channel Islands Recovery Plan. Portland, Oregon: U.S. Fish & Wildlife Service, Region 1. p.93.

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This profile was updated on 3/4/2010