CPC Plant Profile: Macfarlane's Four-o'clock
Search / Plant Profile / Mirabilis macfarlanei
Plant Profile

Macfarlane's Four-o'clock (Mirabilis macfarlanei)

The purplish stem and leathery leaves of Mirabilis macfarlanei. Photo Credit: Tom Kaye
Description
  • Global Rank: N/A
  • Legal Status: N/A
  • Family: Nyctaginaceae
  • State: ID, OR
  • Nature Serve ID: 148885
  • Date Inducted in National Collection: 04/04/1991

This showy plant is quite something if you encounter it in the dry areas of Eastern Oregon and Western Idaho. Often growing on dry, steep slopes high above the river, this four-o'clock, with bright magenta flowers and purplish stems, stands out on the brownish hillsides. Mirabilis macfarlanei was listed as Endangered by the US Fish and Wildlife Service in 1979. An initial recovery plan was created in 1985. It called for baseline studies, determination of population trends, and periodic sampling of populations. The species was downlisted to Threatened in 1996 due to the discovery of additional populations and successful recovery efforts. A revised recovery plan was finalized in 2000. Above ground, the plant does not look very large. It may consist of a few trailing branches up to a couple of feet across. However, underground, the plant has a thick taproot that may grow up to 8 feet deep! This large underground structure enables it to remain dormant in poor growth years or to recover from above ground disturbances. The species was named after Ed MacFarlane, who was a riverboat pilot on the Snake River for over 30 years. Ed MacFarlane did not discover the species. It was shown to him by Harold St. John, a botanist, on a trip up the Snake River. For unknown reasons, St. John did not publish his find. Later, Ed MacFarlane showed two other botanists, Lincoln Constance and Reed Rollins, the plant. They described the species and named it after the pilot (Pilz 1978 in Kaye and Meinke 1992).

Participating Institutions
Updates
  • 10/17/2020
  • Reintroduction

Approximately 400 rhizomes were transplanted from an area of land slides and road construction to a Research Natural Area in 1998 and 1999 (USFWS 2000). 60 rhizomes were transplanted to a fenced exclosure within a Research Natural Area (RNA) in 1988 (USFWS 2000).

  • 10/17/2020
  • Orthodox Seed Banking

Seed from sites in Idaho and Oregon stored at The Berry Botanic Garden.

  • 10/17/2020
  • Seed Collection

Seed from sites in Idaho and Oregon stored at The Berry Botanic Garden.

  • 10/17/2020
  • Propagation Research

Initial germination trials at the Berry Botanic Garden indicated a preference for alternating temperatures. Seeds were subjected to four treatments: Either direct placement into 68F (20C) or alternating 50/68F (10/20C) or 8 weeks of cold stratification followed by 68F (20C) or 50/68F (10/20C). Treatments placed in alternating 50/68F showed 40% germination while both treatments placed in 68F showed 20% germination. Cold stratification had no effect. These results are not conclusive as seed numbers were low (BBG File).

  • 10/17/2020
  • Genetic Research

Genetic studies of Mirabilis macfarlanei utilizing isozymes. M. macfarlanei has lower genetic diversity compared to other plant species with similar life histories. Gene flow was found to decrease as the distance between populations increased. The different populations were found to have relatively high levels of genetic differentiation and small populations were found to have alleles (genes) that were not present in larger populations (Barnes et al. 1994). Genetic analysis, using isozymes, of the genetic diversity between and among 8 populations and the extent of clonality in 4 populations from Idaho (Barnes et al. 1997).

  • 10/17/2020
  • Reproductive Research

Long term monitoring of three populations. Population numbers appear to be stable (Kaye et al. 1990, Kaye and Meinke 1992, and Kaye 1995). Preliminary monitoring on the effects of cattle on Mirabilis macfarlanei. Two plots at one location were placed inside a cattle exclosure (non-grazed) and three were placed outside (grazed) to compare. Plant height was significantly greater in plots inside the cattle exclosure than outside. However, plant diameter and number of inflorescences did not differ with grazing treatment (Kaye 1995).Determination of breeding system. Inflorescences were bagged before flowers opened. Seed was collected from both bagged and un-bagged inflorescences. Bagged flowers did produce seed, indicating that the species is self-compatible. Seed set was slightly greater in un-bagged inflorescences than in bagged, indicating that insects do pollinate the flowers and contribute to higher reproduction levels than obtained through selfing (Kaye et al. 1990)

Clarice Mendoza
  • 11/30/2017

It was threatened by many things, including: trampling, grazing, disease, insect damage and horticultural collecting.

Nature Serve Biotics
  • 05/02/2017

A narrow endemic of the canyon slopes above the Snake, Salmon, and Imnaha Rivers in western Idaho and extreme northeastern Oregon. The species' global range is approximately 46 km by 28.5 km. Fewer than 20 occurrences are currently known, and these vary in population size from a few to over 1000 plants. Most sites are less than 4000 square meters in size. The majority of the populations face few or no direct serious threats. However, canyon grassland communities at most sites have been degraded by past management, land use, and invasive species. The United States Fish and Wildlife Service (2009) states that major threats are indirect effects of domestic livestock grazing and invasion of exotic plants with the subsequent increase in wildfires. Minor threats include human trampling, off-road vehicle use, construction, pest damage, maintenance of roads and trails, and roadside herbicidal treatments.

Edward Guerrant, Ph.D.
  • 01/01/2010

Grazing and trampling by native and domestic animals. Invasion of exotic (non-native) plants (USFWS 2000). Collection for horticultural use (Meinke 1982). Damage to plants and habitat from human trampling, Off-road vehicle (ORV) use, construction a

Edward Guerrant, Ph.D.
  • 01/01/2010

Currently 11 populations in Idaho and Oregon with a total population and estimated 8,000 to 9,000 individuals (based on 39,00 to 44,000 stems) (Craig Johnson in litt. 1999 in U.S. Fish and Wildlife Service, 2000). Because of clonality, it is difficult to determine the number of genetic individuals (Barnes et al. 1997).

Edward Guerrant, Ph.D.
  • 01/01/2010

Long term monitoring of three populations. Population numbers appear to be stable (Kaye et al. 1990, Kaye and Meinke 1992, and Kaye 1995). Preliminary monitoring on the effects of cattle on Mirabilis macfarlanei. Two plots at one location were placed inside a cattle exclosure (non-grazed) and three were placed outside (grazed) to compare. Plant height was significantly greater in plots inside the cattle exclosure than outside. However, plant diameter and number of inflorescences did not differ with grazing treatment (Kaye 1995). Determination of breeding system. Inflorescences were bagged before flowers opened. Seed was collected from both bagged and un-bagged inflorescences. Bagged flowers did produce seed, indicating that the species is self-compatible. Seed set was slightly greater in un-bagged inflorescences than in bagged, indicating that insects do pollinate the flowers and contribute to higher reproduction levels than obtained through selfing (Kaye et al. 1990). Genetic studies of Mirabilis macfarlanei utilizing isozymes. M. macfarlanei has lower genetic diversity compared to other plant species with similar life histories. Gene flow was found to decrease as the distance between populations increased. The different populations were found to have relatively high levels of genetic differentiation and small populations were found to have alleles (genes) that were not present in larger populations (Barnes et al. 1994). Genetic analysis, using isozymes, of the genetic diversity between and among 8 populations and the extent of clonality in 4 populations from Idaho (Barnes et al. 1997). Initial germination trials at the Berry Botanic Garden indicated a preference for alternating temperatures. Seeds were subjected to four treatments: Either direct placement into 68F (20C) or alternating 50/68F (10/20C) or 8 weeks of cold stratification followed by 68F (20C) or 50/68F (10/20C). Treatments placed in alternating 50/68F showed 40% germination while both treatments placed in 68F showed 20% germination. Cold stratification had no effect. These results are not conclusive as seed numbers were low (BBG File).

Edward Guerrant, Ph.D.
  • 01/01/2010

One new transplanted population was established by the Bureau of Land Management (BLM) (USFWS 2000). Habitat Management Plans have been developed and monitoring has occurred for several populations in Idaho by the BLM (USFWS 2000). Several sites on Forest Service land have been fenced to exclude cattle (USFWS 2000). Seed from sites in Idaho and Oregon stored at The Berry Botanic Garden. Approximately 400 rhizomes were transplanted from an area of land slides and road construction to a Research Natural Area in 1998 and 1999 (USFWS 2000). 60 rhizomes were transplanted to a fenced exclosure within a Research Natural Area (RNA) in 1988 (USFWS 2000).

Edward Guerrant, Ph.D.
  • 01/01/2010

Route recreational trails and facilities away from populations (Meinke 1982). Fence populations to prevent grazing (Meinke 1982). Monitor Mirabilis. macfarlanei population trends and habitat conditions (USFWS 2000). Conduct surveys in potential habitat areas. Manage and protect any newly discovered populations (USFWS 2000). If warranted, establish and maintain new populations on areas where Mirabilis macfarlanei has been extirpated (USFWS 2000). Random samples of soil should be gathered to test for the presence of a soil seed bank (Kaye et al. 1992). Study the relative contribution of sexual versus vegetative reproduction further (USFWS 2000). Control invasive Bromus tectorum (cheatgrass) (USFWS 2000). Manage herbicide and pesticide use (USFWS 2000). Conduct demographic monitoring if populations decline by more than 25% over a 3 year period (USFWS 2000). Conduct research on pollinators (USFWS 2000). Conduct inventory of suitable habitat, especially on the Oregon side of the Snake River, to locate new populations.

Edward Guerrant, Ph.D.
  • 01/01/2010

Collect and store seeds from populations across the range. Determine optimum germination procedures.

MORE

Be the first to post an update!

Photos
Newsletters
Nomenclature
Taxon Mirabilis macfarlanei
Authority Constance & Rollins
Family Nyctaginaceae
CPC Number 2868
ITIS 19653
USDA MIMA2
Common Names MacFarlane's Four-o'clock
Associated Scientific Names Mirabilis macfarlanei
Distribution This taxon is natively found in the Blue Mountains of Oregon, specifically around the Imnaha River and Snake River, and Idaho, in the lower Salmon River Canyon and around the Snake River.
State Rank
State State Rank
Idaho S2
Oregon S1
Habitat

MacFarlane's four-o'clock is found on slopes that range from extremely steep to nearly flat, but are always covered with sandy to talus (gravel and cobble) substrate. Elevations range from 1000 to 3000 ft (300-900 m).

Ecological Relationships

Mirabilis macfarlanei is a taprooted herbaceous perennial that reproduces by seed, but also colonizes via long spreading rhizomes. Individual plants may produce a few to several hundred stems in clusters ranging up to about nine square meters in size (Callihan 1988 in Mancuso 1996). Because many stems may arise from a single taproot, it is difficult to accurately determine the number of individuals in each population. What appear to be many individuals (ramets) may in fact be comprised of only a few genetic individuals (genets). The long, thick taproot helps the plant survive unfavorable climactic conditions as well as damage and disturbances. The underground stems of Mirabilis macfarlanei can survive most natural fires, especially since they most occur later in the summer, when the plant is dormant. (Based on conversations with Craig Johnson, Cottonwood District BLM, concerning an Idaho population affected by wildfire).

Individual plants have been observed to live over 20 years (USFWS 2000), but seedling recruitment is low. In the wild, only 12% of seedlings remained alive after two years of observation (Kaye 1995). The plants are at least partially self-compatible.

Insect pollination may not be crucial to short-term population survival, as plants can produce seed without them. However, insect pollination is crucial to the long-term survival of the species. Without pollinators, inbreeding depression may develop and lead to a decrease in population viability (Kaye et al. 1990). This will hinder the species' ability to adapt to changing conditions. The large magenta flowers are pollinated by bumblebees (Bombus fervidus), Tetralonia sp. and Anthophora sp. (large solitary bees) (Kaye et al. 1992). The protection of Mirabilis macfarlanei is especially important because it is host to a rare moth that was discovered in 1983. This Heliodinid moth (Lithariapteryx sp.) is host specific to M. macfarlanei. The moth larvae only feeds on the leaves and flowers of Mirabilis macfarlanei (Baker 1985). In the interests of biodiversity, it is important to preserve both the rare moth and the rare four-o'clock. Because the moth's feeding preferences have the capability of reducing reproduction of the four-o'clock, it is important to protect large numbers of plants.

Habitat occupied by Mirabilis macfarlanei was found to have a greater density of native grasses than adjacent unoccupied habitat (Kaye 1992). Unoccupied habitat contained far more exotic (non-native) species such as yellow starthistle, toadflax and spotted knapweed. This suggests that M. macfarlanei populations require high quality native grasslands to ensure their long-term survival.
 

Pollinators
Common Name Name in Text Association Type Source InteractionID
Bees
Solitary bees Confirmed Pollinator Link
Bumble bees Bombus fervidus Confirmed Pollinator Link

Donate to CPC to Save this Species

CPC secures rare plants for future generations by coordinating on-the-ground conservation and training the next generation of plant conservation professionals. Donate today to help save rare plants from extinction.

Donate Today