Trillium ovatum

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Trillium ovatum
Trillium ovatum - Aldergrove Regional Park.jpg
Pacific trillium blooming in Aldergrove Regional Park (British Columbia, Canada).
Status TNC G5.svg
Secure  (NatureServe) [1]
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Monocots
Order: Liliales
Family: Melanthiaceae
Genus: Trillium
Species:
T. ovatum
Binomial name
Trillium ovatum
Synonyms [3] [4]
T. ovatum var. oettingeri
    • Trillium ovatum subsp. oettingeriMunz & Thorne
T. ovatum var. ovatum
    • Trillium californicumKellogg
    • Trillium obovatumHook.
    • Trillium ovatum f. maculosumCase & R.B.Case
    • Trillium ovatum var. stenosepalumR.R.Gates
    • Trillium venosumR.R.Gates

Trillium ovatum, the Pacific trillium, also known as the western wakerobin, western white trillium, or western trillium, is a species of flowering plant in the family Melanthiaceae. [1] [5] [6] [7] It is the most widespread and abundant trillium in western North America. Its type specimen was gathered by Meriwether Lewis during the return trip of the Lewis and Clark Expedition in 1806.

Contents

Description

The most widespread of the western North American trilliums, Trillium ovatum varies greatly within its range. Despite this, T. ovatum closely resembles the eastern T. grandiflorum. Apart from geographic location, the two species are not easily distinguished. [8]

Trillium ovatum is a perennial herbaceous plant that spreads by means of underground rhizomes. At maturity, each plant has one or two flowering scapes, each 20 to 50 cm (8 to 19.5 in) in length. The specific epithet ovatum means "egg-shaped", which refers to the petals, not the leaves. The latter are generally ovate-rhombic, 7 to 12 cm (3 to 5 in) long by 5 to 20 cm (2 to 8 in) wide. [5]

The flower sits on a pedicel 2 to 6 cm (1 to 2.5 in) in length. The sepals are 15 to 50 mm (0.59 to 1.97 in) long and 6 to 20 mm (0.24 to 0.79 in) wide, while the petals are 15 to 70 mm (0.59 to 2.76 in) long and 10 to 40 mm (0.39 to 1.57 in) wide. Typically the flower opens white and becomes pink with age, but in the Smith River Canyon area of northern California and southern Oregon, the petals become almost barn-red. [9]

Taxonomy

Trillium ovatum was first described by the German–American botanist Frederick Traugott Pursh in 1813. [2] The type specimen for this species was gathered by Meriwether Lewis along the Columbia River during the return trip of the Lewis and Clark Expedition in 1806. [10]

As of April 2024, the following varieties are accepted by Plants of the World Online in addition to Trillium ovatumPursh: [11]

Trillium ovatum var. oettingeri was first described as Trillium ovatum subsp. oettingeri by the American botanists Philip Alexander Munz and Robert Folger Thorne in 1973. [12] [13] The subspecific name oettingeri honors Frederick W. Oettinger who collected the type specimen in July 1967. The type is one of about 1,500 specimens collected by Oettinger in the Marble Mountain Wilderness of the Salmon Mountains in western Siskiyou County, California. Hence Oettinger's trillium is also known as the Salmon Mountains wakerobin. [14]

Trillium ovatum var. oettingeri itself was treated by Frederick W. Case Jr. in Flora of North America in 2002. [15] Unlike the typical variety ovatum, variety oettingeri has leaves with short petioles and linear flower petals. [16] [17] In 2024, the taxon was recommended at species rank based on morphological data and phylogenetic analysis. [18] [19]

Trillium ovatum var. stenosepalum was described by the Canadian-born geneticist Reginald Ruggles Gates in 1917. [20] Its type specimen was collected in Helena, Montana in 1891. [21] The epithet stenosepalum means "narrow-sepalled", the primary difference between it and typical Trillium ovatum. As of April 2024, Trillium ovatum var. stenosepalumR.R.Gates is a synonym for Trillium ovatum var. ovatum, [22] [23] but recent evidence suggests the taxon may be a distinct species. [24]

Trillium ovatum f. maculosumCase & R.B.Case refers to a form with mottled leaves that occurs in northern California. Its type specimen was collected in Mendocino County in 1996. It is the only reported instance of a pedicellate Trillium with mottled leaves. [25] [16] There is no evidence that f. maculosum is distinct from typical Trillium ovatum. [26]

The names Trillium ovatum f. hibbersoniiT.M.C.Taylor & Szczaw. and Trillium ovatum var. hibbersonii(T.M.C.Taylor & Szczaw.) G.W.Douglas & Pojar are synonyms for Trillium hibbersonii (T.M.C.Taylor & Szczaw.) D.O'Neill & S.B.Farmer. [27] Despite its provenance, Trillium hibbersonii is not related to Trillium ovatum, but rather it is a member of subgenus Trillium, the Trillium erectum group. [28] [29]

Distribution and habitat

Trillium ovatum sensu lato is the most widespread and abundant trillium in western North America. [30] [31] It ranges from Monterey County in central California northward throughout the California Coast Ranges to Vancouver Island and southwestern British Columbia. It also occurs in the Rocky Mountains from southeastern British Columbia and the tip of southwestern Alberta, southward through Idaho, eastern Washington and northeastern Oregon, and southeastward through western Montana. [32] There is a small, isolated population in northern Colorado and southern Wyoming. [33] It is often found growing in coniferous and mixed coniferous-deciduous forests, in and around alder thickets and shrubs. [25] Along the California coast, it is commonly found under coast redwood and mixed evergreen forest. [7] At Lolo Pass, Montana, it grows under spruce and Douglas fir in ravines along mountain streams. [34] It does not grow in the dry chaparral inland from the redwood and Douglas fir forests of California and Oregon, nor on ridges where the trees are sparse.

Trillium ovatum var. oettingeri is endemic to a relatively small region in northwestern California. It occurs primarily in the Salmon Mountains, a subrange of the Klamath Mountains, in southwestern Siskiyou County, northern Trinity County, and northeastern Humboldt County. Smaller populations are known to occur in the Cascade Range east of Mount Shasta straddling the border between Siskiyou County and Shasta County. [35] It is found growing at elevations from 4,000–6,300 feet (1,200–1,900 m), often in cold mountain streams, on the banks of mountain lakes, or at the base of cliffs where late summer snow patches linger. [36]

The distribution of Trillium ovatum var. stenosepalum is inconsistently reported in the literature. After examining specimens from Montana, Idaho, Oregon, Washington, and California, Gates (1917) deduced that the taxon ranged from "western Montana and southern Washington to middle California (Santa Cruz Mountains)". [37] More recently, Wayman et al. (2024) concluded that the taxon "occurs in the Rocky Mountains" of Idaho, Montana, Washington, and Colorado, with the caveat that "additional field and lab work are necessary". [38]

Ecology

Flowers bloom late February in the southern part of its range, and in March or April elsewhere. Citizen science observations of flowering plants of this species peak during the first week of April. [39] For comparison, when Trillium grandiflorum is fully open in eastern North America, T. ovatum is already fading in western North America. Apparently T. ovatum lacks sufficient winter hardiness to flourish east of the continental divide. [30] [40]

The life-cycle stages of T. ovatum include a cotyledon stage, a one-leaf vegetative stage, a three-leaf vegetative (juvenile) stage, a three-leaf reproductive (flowering) stage, and a three-leaf nonflowering regressive stage. An example of the latter involves a transition from the three-leaf flowering stage to a three-leaf nonflowering regressive stage. Approximately one of every four reproductive plants regresses to a nonflowering state in any given year. [41] Under the right conditions, individuals may undergo extended dormancy, that is, they may cease above-ground growth for one or more years. In western Montana, dormancy was observed in all adult stage classes, with most plants returning to above ground status in a year or two, although some plants exhibited dormancy for 35 years. [42]

Conservation

In 2019, the global conservation status of Trillium ovatum was determined to be Secure (G5). [1] [43] At the same time, varieties Trillium ovatum var. oettingeri and var. ovatum were ranked Apparently Secure (T4) and Secure (T5), respectively. [44] [45] All known occurrences of variety oettingeri fall within protected areas in northern California but since the effects of wildfire and climate change are unknown, continued monitoring of existing populations is recommended. [46]

Related Research Articles

<i>Trillium</i> Genus of flowering plants

Trillium is a genus of about fifty flowering plant species in the family Melanthiaceae. Trillium species are native to temperate regions of North America and Asia, with the greatest diversity of species found in the southern Appalachian Mountains in the southeastern United States.

<i>Trillium chloropetalum</i> Species of flowering plant

Trillium chloropetalum, also known as giant trillium, giant wakerobin, or common trillium, is a species of flowering plant in the family Melanthiaceae. It is endemic to the western U.S. state of California, being especially frequent in and around the San Francisco Bay Area.

<i>Trillium erectum</i> Species of flowering plant

Trillium erectum, the red trillium, also known as wake robin, purple trillium, bethroot, or stinking benjamin, is a species of flowering plant in the family Melanthiaceae. The plant takes its common name "wake robin" by analogy with the European robin, which has a red breast heralding spring. Likewise Trillium erectum is a spring ephemeral plant whose life-cycle is synchronized with that of the forests in which it lives. It is native to the eastern United States and eastern Canada from northern Georgia to Quebec and New Brunswick.

<i>Trillium grandiflorum</i> Species of flowering plant

Trillium grandiflorum, the white trillium, large-flowered trillium, great white trillium, white wake-robin or French: trille blanc, is a species of flowering plant in the family Melanthiaceae. A monocotyledonous, herbaceous perennial, the plant is native to eastern North America, from northern Quebec to the southern parts of the United States through the Appalachian Mountains into northernmost Georgia and west to Minnesota. There are also several isolated populations in Nova Scotia, Maine, southern Illinois, and Iowa.

<i>Hepatica</i> Genus of flowering plants in the buttercup family Ranunculaceae

Hepatica is a genus of herbaceous perennials in the buttercup family, native to central and northern Europe, Asia and eastern North America. Some botanists include Hepatica within a wider interpretation of Anemone.

<i>Pseudotrillium</i> Genus of flowering plants

Pseudotrillium is a monotypic genus of flowering plant in the family Melanthiaceae. Its sole species, Pseudotrillium rivale, is commonly known as the brook wakerobin. It is endemic to the Siskiyou Mountains of southern Oregon and northern California. The Latin specific epithet rivale means “growing by streams”, with reference to a preferred habitat.

<i>Trillium luteum</i> Species of plant

Trillium luteum, the yellow trillium or yellow wakerobin, is a species of flowering plant in the bunchflower family Melanthiaceae. It is a member of the Trillium cuneatum complex, a closely related group of sessile-flowered trilliums. The species is endemic to the southeastern United States, especially in and around the Great Smoky Mountains of eastern Tennessee and western North Carolina.

<i>Trillium cuneatum</i> Species of flowering plant

Trillium cuneatum, the little sweet betsy, also known as whip-poor-will flower, large toadshade, purple toadshade, and bloody butcher, is a species of flowering plant in the family Melanthiaceae. It is a member of the Trillium cuneatum complex, a subgroup of the sessile-flowered trilliums. It is native to the southeastern United States but is especially common in a region that extends from southern Kentucky through central Tennessee to northern Alabama. In its native habitat, this perennial plant flowers from early March to late April. It is the largest of the eastern sessile-flowered trilliums.

<i>Trillium sessile</i> Species of flowering plant

Trillium sessile is a species of flowering plant in the bunchflower family Melanthiaceae. The specific epithet sessile means "attached without a distinct stalk", an apparent reference to its stalkless flower. It is commonly known as toadshade or toad trillium. It is also called sessile trillium or sessile-flowered wake-robin, however it is not the only member of the genus with a sessile flower.

<i>Geum triflorum</i> Species of flowering plant

Geum triflorum, commonly known as prairie smoke, old man's whiskers, or three-flowered avens, is a spring-blooming perennial herbaceous plant of the Rosaceae family. It is a hemiboreal continental climate species that is widespread in colder and drier environments of western North America, although it does occur in isolated populations as far east as New York and Ontario. It is particularly known for the long feathery plumes on the seed heads that have inspired many of the regional common names and aid in wind dispersal of its seeds.

<i>Tiarella trifoliata</i> Species of flowering plant

Tiarella trifoliata, the three-leaf foamflower, is a species of flowering plant in the family Saxifragaceae. The specific name trifoliata means "having three leaflets", a characteristic of two of the three recognized varieties. Also known as the laceflower or sugar-scoop, the species is found in shaded, moist woods in western North America.

<i>Trillium lancifolium</i> Species of flowering plant

Trillium lancifolium, the lanceleaf wakerobin, lance-leaved trillium, or narrow-leaved trillium, is a species of plants native to the southeastern United States. It is known to occur in Alabama, Florida, Georgia, Mississippi, South Carolina, and Tennessee. The species is imperiled in Alabama and Florida, and critically imperiled in South Carolina and Tennessee.

<i>Trillium sulcatum</i> Species of flowering plant

Trillium sulcatum is a species of flowering plant in the bunchflower family Melanthiaceae. It is a member of the Erectum group, a group of species typified by Trillium erectum. The specific name sulcatum means "furrowed, grooved, or sulcate", which describes the tips of the sepals. It is most abundant on the Cumberland Plateau in central Tennessee and eastern Kentucky where it blooms in April and May. The species is commonly known as the southern red trillium or furrowed wakerobin.

<i>Trillium pusillum</i> Species of flowering plant

Trillium pusillum is a species of flowering plant in the family Melanthiaceae known by the common names dwarf trillium, least trillium and dwarf wakerobin. It is native to the southeastern and south-central United States from Oklahoma to Maryland.

<i>Trillium petiolatum</i> Species of flowering plant

Trillium petiolatum, the Idaho trillium, also known as the long-petioled trillium or round-leaved trillium, is a species of flowering plant in the family Melanthiaceae. It is native to the northwestern United States, in Idaho, Oregon, and Washington. Its type specimen was gathered by Meriwether Lewis during the return trip of the Lewis and Clark Expedition in 1806.

<i>Trillium angustipetalum</i> Species of flowering plant

Trillium angustipetalum, with the common name is narrowpetal wakerobin, is a species of Trillium, plants which may be included within the Liliaceae or the newer family Melanthiaceae.

<i>Trillium crassifolium</i> Species of flowering plant

Trillium crassifolium, the Wenatchee Mountains trillium, is a species of flowering plant in the bunchflower family Melanthiaceae. It was previously thought to be endemic to the Wenatchee Mountains in Washington but recent findings suggest its range extends into Oregon and Idaho as well.

Trillium tennesseense, the Tennessee trillium, is a species of flowering plant in the family Melanthiaceae. It is found exclusively within two counties in northeastern Tennessee. Due to its limited range, it is designated as a critically imperiled species.

<i>Trillium hibbersonii</i> Species of flowering plant

Trillium hibbersonii is a species of flowering plant in the bunchflower family Melanthiaceae. The specific epithet hibbersonii honors the English Canadian surveyor John Arthur Hibberson (1881–1955) who first collected this plant in 1938 on Vancouver Island in British Columbia. Hibberson and his son propagated the trilliums, selling them to buyers in England and other European countries. In 1968, Leonard Wiley coined the Latin name Trillium hibbersonii, a name that has since been used by horticulturists without reservation.

Trillium scouleri is a species of flowering plant in the bunchflower family Melanthiaceae.

References

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Bibliography