Phemeranthus rugospermus (Holz.) Kiger
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Basis for Listing
Phemeranthus rugospermus (rough-seeded fameflower) was first discovered in Minnesota by Douglas Houghton in 1832 on the St. Croix River at Taylor’s Falls in Chisago County. At the time, Houghton was serving as a surgeon and naturalist on the Schoolcraft Expedition that was searching for the headwaters of the Mississippi River. This remarkable discovery, as described by Rittenhouse and Voss (1962), was made on the igneous rocks along a portage at the height of the falls.
Surveys in recent years have expanded the known range of P. rugospermus in Minnesota (Eastern Broadleaf Forest Province) and across the United States. When the species was designated endangered in Minnesota in 1984, there were only four known populations in the state. Surveys since that date have discovered at least 22 additional sites, however, these records likely represent only eight population centers. Although this species is still quite rare in Minnesota, its status was down-listed from endangered to threatened in 2013.
Phemeranthus (fameflower) is a very distinctive genus. The flowers have 2 sepals and 5 pinkish petals, 8-13 mm (0.3-0.5 in.) long, which open only in the afternoon of a single day (Kiger 2003). The leaves are succulent and tubular, distinctly round in cross-section. There are two species of Phemeranthus in Minnesota: P. rugospermus and P. parviflorus (small-flowered fameflower); they look very much alike and occur in similar habitats. Phemeranthus rugospermus has 12-28 stamens and finely wrinkled seeds, while P. parviflorus has 4-8 stamens and smooth seeds.
Most known populations of P. rugospermus occur in dry, open, sandy habitats. This includes sandy terraces, fluvial sand dunes, sand barrens, savannas and prairie openings. Trees may be absent, or there can be scattered Pinus banksiana (jack pine), Quercus ellipsoidalis (northern pin oak), or Quercus velutina (black oak). A less frequent habitat is rock outcrops and dry, igneous rock ledges.
Biology / Life History
From all available evidence, P. rugospermus occupies a narrow ecological niche. It seems to be limited by its need for direct sunlight and an absence of competition. It is supremely drought tolerant, evidenced by its ability to remain green and succulent even under drought conditions. It is perhaps this quality that allows it to succeed in habitats where most competitors fail. Each plant has several flowers, but each flower is open for only a few hours during the afternoon of a single day. Flowers are insect pollinated, though specific pollinators are unknown. Each fruit is a dry, three-part pod that contains numerous small, flat seeds (Cochrane 1993; Pavlovic 1995).
Conservation / Management
Although P. rugospermus is damaged by fire, it usually grows in open sand where there may be too little fuel to carry a fire. In these instances, fire may be beneficial in that it may help control the invasion of woody plants. Additional threats include residential development, pine plantations, livestock grazing, and conversion of sand prairie habitats to agricultural fields.
Best Time to Search
The best time to search for P. rugospermus is not simply during its seasonal flowering period, which extends from about the middle of June through the middle of July, but also during its diurnal flowering cycle. Plants are very inconspicuous without flowers. Searches of known locations in the morning or early afternoon often record plants as rare or uncommon. However, searches of the same sites in late afternoon, when the flowers are open, often reveal plants to be quite abundant.
Conservation Efforts in Minnesota
Surveys conducted by the Minnesota Biological Survey resulted in the discovery or rediscovery of many of the known locations of P. rugospermus. Several of the sites receive protection within State Parks, Scientific and Natural Areas, and Wildlife Management Areas. Although these sites are generally managed to preserve and enhance the natural vegetation, no effort has been made to evaluate the effects of management on P. rugospermus.
Welby Smith, MN DNR, 1988, 2008, and 2017
Cochrane, T. S. 1993. Status and distribution of Talinum rugospermum Holz. (Portulacaceae). Natural Areas Journal 13(1):33-41.
Coffin, B., and L. Pfannmuller, editors. 1988. Minnesota's endangered flora and fauna. University of Minnesota Press, Minneapolis. 473 pp.
Holzinger, J. M. 1899. Some notes from my flower garden. Asa Gray Bulletin 7(9):80-81.
Kiger, R. W. 2003. Phemeranthus. Pages 488-495 in Flora of North America Editorial Committee, editors. Flora of North America north of Mexico. Volume 4. Oxford University Press, New York, New York.
Minnesota Department of Natural Resources. 2003. Field guide to the native plant communities of Minnesota: the Laurentian mixed forest province. Ecological Land Classification Program, Minnesota County Biological Survey, and Natural Heritage and Nongame Research Program. Minnesota Department of Natural Resources, St. Paul, Minnesota. 352 pp.
Minnesota Department of Natural Resources. 2005. Field guide to the native plant communities of Minnesota: the eastern broadleaf forest province. Ecological Land Classification Program, Minnesota County Biological Survey, and Natural Heritage and Nongame Research Program. Minnesota Department of Natural Resources, St. Paul, Minnesota. 394 pp.
Minnesota Department of Natural Resources, Division of Ecological Resources. 2008. Rare species guide: an online encyclopedia of Minnesota's rare native plants and animals [Web Application]. Minnesota Department of Natural Resources, St. Paul, Minnesota. Accessed 1 July 2009.
NatureServe. 2009. NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.1. NatureServe, Arlington, Virginia.
Pavlovic, N. B. 1995. Habitat, disturbance, density dependence and the abundance of Fame Flower (Talinum rugospermum). Thesis, University of Illinois at Chicago, Chicago, Illinois. xix + 198 pp.
Rittenhouse, J. L., and E. G. Voss. 1962. Douglass Houghton's botanical collections in Michigan, Wisconsin, and Minnesota on the Schoolcraft expedition of 1832. The Michigan Botanist 1:61-70.