''Trollius laxus'' is a rare

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (). The term angiosperm is derived from the Ancient Greek, Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed with ...

species in the buttercup family,

Ranunculaceae Ranunculaceae (, buttercup or crowfoot family; Latin "little frog", from "frog") is a family (biology), family of over 2,000 known species of flowering plants in 43 genera, distributed worldwide. The largest genera are ''Ranunculus'' (600 spec ...

. It is native to

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and is considered to have two subspecies, one with a distribution is the east and one in the west. Common names for ''Trollius laxus'' include American globeflower and American spreading globeflower. The American Globeflower, ''Trollius laxus'' is an endangered species of flowering plants Native to Northeastern United States. This species of plants is limited in range by their ability to exclusively survive in wetlands and marshes. Thus, clusters of the species are constantly threatened by the ever-changing hydrology of the range they are confined to.

Subspecies

The two subspecies of ''Trollius laxus'' are: *''T. laxus'' ssp. ''albiflorus'' *''T. laxus'' ssp. ''laxus'' Subspecies ''albiflorus'' has a distribution over southwestern Canada and northwestern United States, while ssp. ''laxus'' has a range in the northeastern U.S., limited to parts of

Connecticut Connecticut ( ) is a U.S. state, state in the New England region of the Northeastern United States. It borders Rhode Island to the east, Massachusetts to the north, New York (state), New York to the west, and Long Island Sound to the south. ...

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and

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Distribution

''Trollius laxus'' is a rare, herbaceous perennial only found in a small range of fens or wetland habitats fed by groundwater in northeastern United States. In these calcium rich fens, the ''T. laxus'' can be locally abundant. They can also be found in

Oregon Oregon ( , ) is a U.S. state, state in the Pacific Northwest region of the United States. It is a part of the Western U.S., with the Columbia River delineating much of Oregon's northern boundary with Washington (state), Washington, while t ...

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British Columbia British Columbia is the westernmost Provinces and territories of Canada, province of Canada. Situated in the Pacific Northwest between the Pacific Ocean and the Rocky Mountains, the province has a diverse geography, with rugged landscapes that ...

and the

Rocky Mountains The Rocky Mountains, also known as the Rockies, are a major mountain range and the largest mountain system in North America. The Rocky Mountains stretch in great-circle distance, straight-line distance from the northernmost part of Western Can ...

Colorado Colorado is a U.S. state, state in the Western United States. It is one of the Mountain states, sharing the Four Corners region with Arizona, New Mexico, and Utah. It is also bordered by Wyoming to the north, Nebraska to the northeast, Kansas ...

. During spring, ''T. laxus'' is one of the first flowers to bloom in the Rocky Mountain. Its distribution is limited by light intensity and hydrology.

Wetlands A wetland is a distinct semi-aquatic ecosystem whose groundcovers are flooded or saturated in water, either permanently, for years or decades, or only seasonally. Flooding results in oxygen-poor ( anoxic) processes taking place, especially ...

and

marshes In ecology, a marsh is a wetland that is dominated by herbaceous plants rather than by woody plants.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p More in general ...

have consistent groundwater discharge which means that water levels will typically be high in these areas. This will result in anoxia and ultimately lower the amount of nutrients present. It is thought that the plants evolved to endure these conditions so that they have less competition for sunlight. While ''T. laxus'' prefers these wetter conditions, the plant can also grow in drier conditions if there is enough

sunlight Sunlight is the portion of the electromagnetic radiation which is emitted by the Sun (i.e. solar radiation) and received by the Earth, in particular the visible spectrum, visible light perceptible to the human eye as well as invisible infrare ...

present. Increased sunlight will increase the biomass of these plants but, there is a threshold before the plant's growth will plateau or even decline. The combination of seasonal drying along with very high light intensities can result in the competitive exclusion of ''T. laxus''. In order for T. laxus to meet this requirement of light intensity and

hydrology Hydrology () is the scientific study of the movement, distribution, and management of water on Earth and other planets, including the water cycle, water resources, and drainage basin sustainability. A practitioner of hydrology is called a hydro ...

, it must sacrifice the size of its range. This is a factor that causes its distribution to be limited.

Habitat and Ecology

''Trollius laxus'' is a

perennial In horticulture, the term perennial ('' per-'' + '' -ennial'', "through the year") is used to differentiate a plant from shorter-lived annuals and biennials. It has thus been defined as a plant that lives more than 2 years. The term is also ...

found predominantly in forested wetlands with cold

alkaline In chemistry, an alkali (; from the Arabic word , ) is a basic salt of an alkali metal or an alkaline earth metal. An alkali can also be defined as a base that dissolves in water. A solution of a soluble base has a pH greater than 7.0. The ...

groundwater Groundwater is the water present beneath Earth's surface in rock and Pore space in soil, soil pore spaces and in the fractures of stratum, rock formations. About 30 percent of all readily available fresh water in the world is groundwater. A unit ...

. This plant is one of the first to flower in the spring from mid-April to early May in

, and the seeds are ripened by mid-June where they are dispersed passively with the help of wind and water. ''Trollius laxus'' has few effective

pollinators A pollinator is an animal that moves pollen from the male anther of a flower to the female stigma of a flower. This helps to bring about fertilization of the ovules in the flower by the male gametes from the pollen grains. Insects are the ma ...

including the sweat bee, the Cuckoo bee, and a fly within the family Tachinidae. Molluscan herbivores such as slugs and snails can cause leaf damage impacting the overall plant community diversity. Slug predation on ''T. laxus'' affects its seedling survival, as well as competition and predation due to the presence of neighboring plants and herbivores. Removing neighboring plants lowers the predation risk on T. Laxus and increases its growth and reproductive success. ''Trollius laxus'' may also occur in forested wetlands so it may be well-adapted to growing under closed forest canopies. Field observations have indicated that both light and groundwater levels affect ''T. laxus'' plant and population vigor, and that the distribution of ''T. laxus'' may be limited by competition with other plants.

Morphology

''Trollius laxus'' is easily identifiable by

botanists This is a list of botanists who have Wikipedia articles, in alphabetical order by surname. The List of botanists by author abbreviation is mostly a list of plant taxonomists because an author receives a standard abbreviation only when that aut ...

due to their showy bright yellow flowers which are globular in shape. When flower is absent, other characteristics can be used to identify the plant. This herbaceous flowering plant with a one to two foot stems, thick and fibrous roots, and basal

leaves A leaf (: leaves) is a principal appendage of the stem of a vascular plant, usually borne laterally above ground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, stem, ...

. The plant can include one or more stems, each with a cream or pale yellow flower up to 5 cm in diameter with 5-7 petaloid sepals. The actual petals are reduced to staminodes with basal nectar glands. Each leaf of ''Trollius laxus'' consists of five three-lobed leaflets that spread horizontally from the tip of the petiole. Each leaflet has sharp teething margins. The leaves sprout on petioles which grow from the base of the plant.

Fruits and flowers

This

herbaceous plant Herbaceous plants are vascular plants that have no persistent woody stems above ground. This broad category of plants includes many perennials, and nearly all annuals and biennials. Definitions of "herb" and "herbaceous" The fourth edition o ...

is one of the first to bloom in the spring. The flowering stalk is usually longer than the leaf stalk. The flowers are terminal, meaning the grow at the tip of the flowering stalk and each stalk has one flower. Each flower has five veiny

sepals A sepal () is a part of the flower of angiosperms (flowering plants). Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom., p. 106 Etymology The term ''sepalum'' ...

and in the center of the flower sit numerous stamens and ten to fifteen petals deep yellow or orange in color. Hidden among the

petals Petals are modified leaves that form an inner whorl surrounding the reproductive parts of flowers. They are often brightly coloured or unusually shaped to attract pollinators. All of the petals of a flower are collectively known as the ''coroll ...

are five or more separate fruits. The fruit of Trollius laxus are dry with each follicle containing three to six seeds on average, and are formed in aggregate on the stems. The flowers of T. laxus range from white to yellow in color with nectar glands at the base, and can grow up to five centimeters in diameter. Both flowering and fruit level are positively correlated with light intensity, possibly due to pollinators being able to travel longer distances after leaving a warmer flower than a colder one. Trollius laxus BB-1913.png , ''Trollius laxus'' illustration

References

{{Taxonbar, from=Q7845287

laxus ''Laxus'' is a genus of nematode worms from the subfamily Stilbonematinae of the family Desmodoridae. Like other members of this subfamily, they are covered by a layer of symbiotic Symbiosis (Ancient Greek : living with, companionship < ...

Plants described in 1807