''Epilobium ciliatum'', known by the common names fringed willowherb, American willowherb, slender willow herb, and northern willow herb is a species of ''

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants th ...

'' in the willowherb family

Onagraceae The Onagraceae are a family of flowering plants known as the willowherb family or evening primrose family. They include about 650 species of herbs, shrubs, and trees North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

, southern

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...

, and

East Asia East Asia is the eastern region of Asia, which is defined in both geographical and ethno-cultural terms. The modern states of East Asia include China, Japan, Mongolia, North Korea, South Korea, and Taiwan. China, North Korea, South Korea and ...

. It is an

introduced species An introduced species, alien species, exotic species, adventive species, immigrant species, foreign species, non-indigenous species, or non-native species is a species living outside its native distributional range, but which has arrived there ...

in much of Eurasia and Australia. This

perennial A perennial plant or simply perennial is a plant that lives more than two years. The term ('' per-'' + '' -ennial'', "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also wide ...

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 of t ...

usually occurs in wetlands, but may be found in a great variety of habitats, including disturbed areas and roadsides, at elevations below .

Description

''Epilobium ciliatum'' is a clumping perennial often exceeding in height. It has thickly veined lance-shaped leaves which may be up to 15 centimeters long toward the base of the plant. The foliage, stem, and

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 ...

are covered in bristly hairs and glands. There are four sepals. The regular, trumpet-shaped flowers have four petals which are so deeply notched they look like four pairs. They are white to light purple or pink with dark veining. There are eight stamens and a club-shaped stigma. The fruit is a narrow, hairy, four-chambered capsule up to 10 centimeters in length which may be held on a long stalk. The seeds are downy and can float for long distances with the wind.

Subspecies

Three

subspecies In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (morphology), but that can successfully interbreed. Not all species ...

are currently recognized: * ''Epilobium ciliatum'' ssp. ''ciliatum'' * ''Epilobium ciliatum'' ssp. ''glandulosum'' — (Lehm.) Hoch & P.H.Raven * ''Epilobium ciliatum'' ssp. ''watsonii'' — (Barbey) Hoch & P.H.RavenUSDA:''Epilobium ciliatum'' ssp. ''watsonii''
/ref>

Taxonomy

''Epilobium ciliatum'' may be a

cryptic species complex In biology, a species complex is a group of closely related organisms that are so similar in appearance and other features that the boundaries between them are often unclear. The taxa in the complex may be able to hybridize readily with each oth ...

. The Rocky Mountain Willowherb (''Epilobium saximontanum'') is sometimes included as yet another subspecies. The three currently recognized subspecies may each constitute a distinct species. If so, ''E. ciliatum'' ssp. ''watsonii'' would perhaps use the name ''E. adenocaulon'' and include those populations, while ''E. ciliatum'' ssp. glandulosum'' would perhaps use the name ''E. bergianum'' and include those populations. The others named ''E. ciliatum'' ssp. ''ciliatum'' populations would remain.

Distribution and habitat

''Epilobium ciliatum'' is native to the southern part of Canada and most of the United States of America. It arrived in northern Europe early in the 20th century and spread rapidly, reaching Finland in about 1920. It is a plant of moist places, stream-sides, ditches, ponds, gardens, roadsides, recently cleared areas and wasteland.

References

External links

Jepson Manual Treatment for ''Epilobium ciliatum''CalFlora database — ''Epilobium ciliatum'' (Slender Willow herb)''Epilobium ciliatum'' — Photo gallery
{{Taxonbar, from=Q164151 ciliatum Flora of North America Flora of southern South America Flora of temperate Asia Flora of the California desert regions Taxa named by Constantine Samuel Rafinesque Flora without expected TNC conservation status