''Trillium petiolatum'', the Idaho trillium, also known as the long-petioled trillium or round-leaved trillium, is a

species In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of ...

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. They include all forbs (flowering plants without a woody stem), grasses and grass-like plants, a vast majority of ...

in the

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Melanthiaceae Melanthiaceae, also called the bunchflower family, is a family of flowering herbaceous perennial plants native to the Northern Hemisphere. Along with many other lilioid monocots, early authors considered members of this family to belong to ...

. It is native to the northwestern

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., federal district, five ma ...

, in

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 W ...

Oregon Oregon () is a state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington, while the Snake River delineates much of its eastern boundary with Idah ...

, and

Washington Washington commonly refers to: * Washington (state), United States * Washington, D.C., the capital of the United States ** A metonym for the federal government of the United States ** Washington metropolitan area, the metropolitan area centered o ...

. The

type specimen In biology, a type is a particular specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally attached. In other words, a type is an example that serves to anchor or centralizes the ...

for this species was gathered by

Meriwether Lewis Meriwether Lewis (August 18, 1774 – October 11, 1809) was an American explorer, soldier, politician, and public administrator, best known for his role as the leader of the Lewis and Clark Expedition, also known as the Corps of Discovery, wi ...

during the return trip of the

Lewis and Clark Expedition The Lewis and Clark Expedition, also known as the Corps of Discovery Expedition, was the United States expedition to cross the newly acquired western portion of the country after the Louisiana Purchase. The Corps of Discovery was a select gr ...

in 1806.

Description

''Trillium petiolatum'' is "without question the least ''Trillium''-like of all trilliums." The

specific epithet In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...

''petiolatum'', meaning "petioled," is intended to draw attention to its very long petioles, which are long. The petioles are nearly as long as the leaf blades, which themselves are long and wide. The round-ovate blades are green but not

mottle Mottle is a pattern of irregular marks, spots, streaks, blotches or patches of different shades or colours. It is commonly used to describe the surface of plants or the skin of animals. In plants, mottling usually consists of yellowish spots ...

d. The petiolate leaves strongly resemble the leaves of the common plantain. Pursh himself observed that ''T. petiolatum'' "has leaves very much like ''

Plantago major ''Plantago major'', the broadleaf plantain, white man's footprint, waybread, or greater plantain, is a species of flowering plant in the plantain family Plantaginaceae. The plant is native to Eurasia. The young, tender leaves can be eaten raw, a ...

''." The scape is long but most of it remains below the surface since the rhizome is deep underground, presumably for protection. Consequently the leaf-whorl and the

sessile Sessility, or sessile, may refer to: * Sessility (motility), organisms which are not able to move about * Sessility (botany), flowers or leaves that grow directly from the stem or peduncle of a plant * Sessility (medicine), tumors and polyps that ...

flower sit at or near ground level. The flower is small, with sepals from long and wide and petals from long and wide. The petals are red, maroon, or purple, but yellow-flowered forms devoid of purple pigments have been identified. Due to its small size and uncharacteristic leaf structure (for a trillium), the plant is inconspicuous and easily overlooked. ''Trillium petiolatum'' shows similarities to both ''T. sessile'' and ''T. recurvatum''. Of the sessile trilliums, only ''T. recurvatum'' and ''T. petiolatum'' have petiolate leaves, but apart from this, the two species have little else in common. Based on flower parts and reproductive organs, ''T. petiolatum'' appears to be more closely related to ''T. sessile''.

Taxonomy

''Trillium petiolatum'' was first described by the German–American botanist

Frederick Traugott Pursh Frederick Traugott Pursh (or Friedrich Traugott Pursch) (February 4, 1774 – July 11, 1820) was a German– American botanist. Born in Großenhain, Saxony, under the name Friedrich Traugott Pursh, he was educated at Dresden Botanical Gardens, ...

in 1813. The

for this

was gathered by

along the Clearwater River (originally called Koos-Koos-Kai-Kai by the

Nez Perce people The Nez Percé (; autonym in Nez Perce language: , meaning "we, the people") are an Indigenous people of the Plateau who are presumed to have lived on the Columbia River Plateau in the Pacific Northwest region for at least 11,500 years.Ames, ...

) during the return trip of the

in 1806.

Distribution

''Trillium petiolatum'' is native to the mountainous areas of the northwestern

, in

, and

Ecology

''Trillium petiolatum'' flowers very early April to late May (depending upon conditions and elevation) but it may bloom earlier upon south-facing slopes. It occurs at elevations from , above stream beds, under scrub brush, and near the edges of coniferous and deciduous forests. No other ''Trillium'' species survives in such harsh conditions. Only the habitat of ''

Pseudotrillium rivale ''Pseudotrillium'' is a monotypic genus of flowering plants in the family Melanthiaceae containing the single species ''Pseudotrillium rivale''. The genus was proposed in 2002 on the basis of morphology and molecular evidence that suggest the pl ...

'', a close relative, approaches the habitat of ''T. petiolatum'' in terms of exposure, openness, and seasonal dryness. Like ''T. ovatum'', ''T. petiolatum'' does not do well in eastern gardens. Like other ''Trillium'' species, ''T. petiolatum'' has a one-leaf vegetative stage followed by a three-leaf vegetative (juvenile) stage. After several years of vegetative growth, the plant finally reaches its three-leaf reproductive (flowering) stage. It has an indefinite life span of many years. Trillium petiolatum- Washington

References

Bibliography

* * *

External links

*
Oregon Flora Project
{{Taxonbar, from=Q3009760 petiolatum Flora of Idaho Flora of Oregon Flora of Washington (state) Endemic flora of the United States Plants described in 1813 Taxa named by Frederick Traugott Pursh