Lepidium papilliferum sign on Snake River Plains

''Lepidium papilliferum'' is a rare species of flowering plant in the

mustard family Brassicaceae () or (the older) Cruciferae () is a medium-sized and economically important family of flowering plants commonly known as the mustards, the crucifers, or the cabbage family. Most are herbaceous plants, while some are shrubs. The le ...

known by the common names Idaho pepperweed and slickspot peppergrass. It is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

Idaho Idaho ( ) is a state in the Pacific Northwest region of the Western United States. To the north, it shares a small portion of the Canada–United States border with the province of British Columbia. It borders the states of Montana and Wyom ...

in the United States, where it is mostly limited to a specific habitat type in the southwestern part of the state. It was federally listed as a threatened species in 2009.USFWS
Listing ''Lepidium papilliferum'' (Slickspot Peppergrass) as a shreatened species throughout its range; Final rule.
''Federal Register'' October 8, 2009. This is an herb growing just a few centimeters to over 20 centimeters tall, and known to approach 40 centimeters. The leaves are divided into many subdivided lobes, the largest blades measuring 4 centimeters in length. The

inflorescence An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are formed o ...

is a

raceme A raceme ( or ) or racemoid is an unbranched, indeterminate type of inflorescence bearing flowers having short floral stalks along the shoots that bear the flowers. The oldest flowers grow close to the base and new flowers are produced as the s ...

of many white flowers. The fruit is a rounded, flattened, winged

silique A silique or siliqua (plural ''siliques'' or ''siliquae'') is a type of fruit (seed capsule) having two fused carpels with the length being more than three times the width. When the length is less than three times the width of the dried fruit i ...

up to 3 or 4 millimeters long by 3 to 4 wide.''Lepidium papilliferum''.
Flora of North America. There is an annual form and a biennial form of the plant, the annual form completing its life cycle in one year and the biennial not producing flowers or seed until its second year. This plant grows in the

sagebrush steppe Sagebrush steppe is a type of shrub-steppe, a plant community characterized by the presence of shrubs, and usually dominated by sagebrush, any of several species in the genus ''Artemisia''.ecosystem An ecosystem (or ecological system) consists of all the organisms and the physical environment with which they interact. These biotic and abiotic components are linked together through nutrient cycles and energy flows. Energy enters the syste ...

, where it can be found in

microsite A microsite is an individual web page or a small cluster of pages which are meant to function as a discrete entity (such as an iFrame) within an existing website or to complement an offline activity. The microsite's main landing page can have its ...

s called slick spots, patches of soil covered in a cryptogamic crust of

cyanobacteria Cyanobacteria (), also known as Cyanophyta, are a phylum of gram-negative bacteria that obtain energy via photosynthesis. The name ''cyanobacteria'' refers to their color (), which similarly forms the basis of cyanobacteria's common name, blu ...

and

algae Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular mic ...

. Occurrences outside of slick spots are rare. Slick spot soil is generally relatively high in sodium and clay, and the spots are mostly bare of vegetation and very slightly indented so that water accumulates. The soil is lighter in color than surrounding soils. In the dry season the water evaporates and the area becomes very dry. Slick spots take a long time to form; those existing now were likely formed during the

Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...

, and then altered early in the

Holocene The Holocene ( ) is the current geological epoch. It began approximately 11,650 cal years Before Present (), after the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene togethe ...

when salt deposits were layered over them by wind. It is thought that slick spots are no longer being formed in today's climate, so when they are destroyed they are permanently lost. The slickspot peppergrass population in the slick spots varies with annual moisture levels; more spring precipitation allows the growth of more plants.''Lepidium papilliferum''.

The Nature Conservancy The Nature Conservancy (TNC) is a global environmental organization headquartered in Arlington, Virginia. it works via affiliates or branches in 79 countries and territories, as well as across every state in the US. Founded in 1951, The Natu ...

. In general, the population is thought to have declined over time. Slick spot habitat in its limited area has been degraded by

agriculture Agriculture or farming is the practice of cultivating plants and livestock. Agriculture was the key development in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that enabled people to ...

grazing In agriculture, grazing is a method of animal husbandry whereby domestic livestock are allowed outdoors to roam around and consume wild vegetations in order to convert the otherwise indigestible (by human gut) cellulose within grass and other ...

of cattle, urban development, and

wildfire A wildfire, forest fire, bushfire, wildland fire or rural fire is an unplanned, uncontrolled and unpredictable fire in an area of Combustibility and flammability, combustible vegetation. Depending on the type of vegetation present, a wildfire ...

. The frequency of wildfire is increasing as the habitat is invaded by

introduced plants Introduction, The Introduction, Intro, or The Intro may refer to: General use * Introduction (music), an opening section of a piece of music * Introduction (writing), a beginning section to a book, article or essay which states its purpose and g ...

such as

cheatgrass ''Bromus tectorum'', known as downy brome, drooping brome or cheatgrass, is a winter annual grass native to Europe, southwestern Asia, and northern Africa, but has become invasive in many other areas. It now is present in most of Europe, southe ...

(''Bromus tectorum'').

References

External links

*Menke, C. A. and T. N. Kaye. (2006)
''Lepidium papilliferum'' (Slickspot peppergrass): Evaluation of trends (1998-2004) and analysis of 2004 habitat integrity and population monitoring data.
BLM, Idaho Dept Fish & Game, Idaho Conservation Data Center, and Institute for Applied Ecology. *Mancuso, M. (2000)
Field investigation for ''Lepidium pappiliferum'' (Slickspot Peppergrass) on Idaho BLM lands in the Mountain Home-Glenns Ferry area.
Idaho Dept. Fish & Game. {{Authority control papilliferum Flora of Idaho Plants described in 1913