Lepidium papilliferum
Encyclopedia
Lepidium papilliferum is a rare species of flowering plant in the mustard family
known by the common names Idaho pepperweed and slickspot peppergrass. It is endemic to Idaho
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.
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
is a raceme
of many white flowers. The fruit is a rounded, flattened, winged silique
up to 3 or 4 millimeters long by 3 to 4 wide. 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
ecosystem
, where it can be found in microsite
es called slick spots, patches of soil covered in a cryptogamic crust
of cyanobacteria and algae
. 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
, and then altered early in the Holocene
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 precipitaton allows the growth of more plants. In general, the population is thought to have declined over time. Slick spot habitat in its limited area has been degraded by agriculture
, grazing
of cattle, urban development, and wildfire
. The frequency of wildfire is increasing as the habitat is invaded by introduced plants
such as cheatgrass (Bromus tectorum).
Brassicaceae
Brassicaceae, a medium sized and economically important family of flowering plants , are informally known as the mustards, mustard flowers, the crucifers or the cabbage family....
known by the common names Idaho pepperweed and slickspot peppergrass. It is endemic to Idaho
Idaho
Idaho is a state in the Rocky Mountain area of the United States. The state's largest city and capital is Boise. Residents are called "Idahoans". Idaho was admitted to the Union on July 3, 1890, as the 43rd state....
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.
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
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. Strictly, it is the part of the shoot of seed plants where flowers are formed and which is accordingly modified...
is a raceme
Raceme
A raceme is a type of inflorescence that is unbranched and indeterminate and bears pedicellate flowers — flowers having short floral stalks called pedicels — along the axis. In botany, axis means a shoot, in this case one bearing the flowers. In a raceme, the oldest flowers are borne...
of many white flowers. The fruit is a rounded, flattened, winged silique
Silique
A silique or siliqua is a fruit of 2 fused carpels with the length being more than three times the width. The outer walls of the ovary usually separate when ripe, leaving a persistent partition...
up to 3 or 4 millimeters long by 3 to 4 wide. 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
The sagebrush steppe is a type of shrub-steppe, which is a dry-xeric environment and plant community found in the Western United States and western Canada...
ecosystem
Ecosystem
An ecosystem is a biological environment consisting of all the organisms living in a particular area, as well as all the nonliving , physical components of the environment with which the organisms interact, such as air, soil, water and sunlight....
, where it can be found in microsite
Microsite
A microsite is an Internet web design term referring to an individual web page or a small cluster of pages which are meant to function as a discreet entity within an existing website or to complement an offline activity...
es called slick spots, patches of soil covered in a cryptogamic crust
Cryptobiotic soil
A Cryptobiotic soil is a biological soil crust composed of living cyanobacteria, green algae, brown algae, fungi, lichens, and/or mosses. Commonly found in arid regions around the world, cryptobiotic soils go by many names, including cryptogamic, microbiotic, or microphytic soils or crusts...
of cyanobacteria and algae
Algae
Algae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms, such as the giant kelps that grow to 65 meters in length. They are photosynthetic like plants, and "simple" because their tissues are not organized into the many...
. 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
Pleistocene
The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....
, and then altered early in the Holocene
Holocene
The Holocene is a geological epoch which began at the end of the Pleistocene and continues to the present. The Holocene is part of the Quaternary period. Its name comes from the Greek words and , meaning "entirely recent"...
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 precipitaton allows the growth of more plants. In general, the population is thought to have declined over time. Slick spot habitat in its limited area has been degraded by agriculture
Agriculture
Agriculture is the cultivation of animals, plants, fungi and other life forms for food, fiber, and other products used to sustain life. Agriculture was the key implement in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that nurtured the...
, grazing
Grazing
Grazing generally describes a type of feeding, in which a herbivore feeds on plants , and also on other multicellular autotrophs...
of cattle, urban development, and wildfire
Wildfire
A wildfire is any uncontrolled fire in combustible vegetation that occurs in the countryside or a wilderness area. Other names such as brush fire, bushfire, forest fire, desert fire, grass fire, hill fire, squirrel fire, vegetation fire, veldfire, and wilkjjofire may be used to describe the same...
. The frequency of wildfire is increasing as the habitat is invaded by introduced plants
Introduced species
An introduced species — or neozoon, alien, exotic, non-indigenous, or non-native species, or simply an introduction, is a species living outside its indigenous or native distributional range, and has arrived in an ecosystem or plant community by human activity, either deliberate or accidental...
such as cheatgrass (Bromus tectorum).
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.
- USDA Plants Profile