Epilobium


Epilobium is a genus of flowering plants in the family Onagraceae, containing about 197 species. The genus has a worldwide distribution. It is most prevalent in the subarctic, temperate and subantarctic regions, whereas in the subtropics and tropics Epilobium species are restricted to the cool montane biomes, such as the New Guinea Highlands.
The taxonomy of the genus has varied between different botanists, but the modern trend is to include the previously recognised genera Boisduvalia, Chamaenerion, Pyrogennema and Zauschneria within Epilobium according to Peter H. Raven, who has extensively studied the willowherbs and merges the other segregate genera into Epilobium. Fringed willowherb is likely a cryptic species complex; apparently these plants also commonly hybridize with their congeners.
Most species are known by the common name willowherbs for their willow-like leaves. Those that were once separated in Boisduvalia are called spike-primroses or boisduvalias. Those Epilobium species previously placed in the Chamaenerion group are known as fireweeds.

Description

Epilobiums are mostly herbaceous plants, either annual or perennial; a few are subshrubs. The leaves are opposite or rarely whorled, simple and ovate to lanceolate in shape. The flowers are actinomorphic with four petals that may be notched. These are usually smallish and pink in most species, but red, orange or yellow in a few. The fruit is a slender cylindrical capsule containing numerous seeds embedded in fine, soft silky fluff which disperses the seeds very effectively in the wind.
The genus name derives from the Greek words "epi" meaning "upon" and "lobos" meaning "lobe", with reference to position of the petals above the ovary.
A number of Epilobium species with slightly asymmetrical magenta flowers and alternate leaves are placed in the genus Chamaenerion, which may be further separated by some authorities into a genus Chamerion. However, Chamerion is not universally accepted.

Habitat and ecology

Willowherbs sensu lato are typically very quick to carpet large swathes of ground and may become key or dominant species of local ecosystems. In the United Kingdom, for example, rosebay willowherb is widely found on mesotrophic soils dominated by false oat-grass, cock's-foot grass, and red fescue, while great willowherb is found in mesotrophic grassland with stinging nettle. These two willowherb species also dominate open habitat early in ecological succession, to the virtual exclusion of other plant life. Broad-leaved willowherb is found characteristically, though not abundantly, in the mesotrophic grasslands with meadowsweet and sometimes the uncommon Greek valerian. Most willowherbs will not tolerate shade trees and thus are limited to more recently disturbed patches, yielding to other plants over time. Consequently, though the genus contains many pioneer plants, rather few of them are invasive weeds of major importance.
Epilobium species are used as food plants by the caterpillars of certain Lepidoptera species, including:

Geometridae
Noctuidae
Sphingidae
The main use of Epilobium by humans is as a herbal supplement in the treatment of prostate, bladder and hormone disorders.
Many of the small willowherb species are nuisance weeds in gardens. Though few are regularly used as ornamental plants, the larger willowherbs may be attractive in ruderal locales. One of the most frequently recognized members of the genus is the circumboreal fireweed, known as rosebay willowherb in the United Kingdom. It rapidly colonizes burnt ground; during the bombing of London in World War II many of the derelict bomb sites were soon covered with these plants, bringing a splash of colour to what was otherwise a very grim scene. It is the floral emblem of Yukon in Canada, Hedmark in Norway and Southern Ostrobothnia in Finland.
Fireweed is used as a sweetener in north-western North America. It is put in candy, jellies, ice cream, syrup, and sxusem. In the late summer its flowers yield pollen and copious nectar which give a rich spicy honey. Its young leaves, roots, and shoots are edible, and rich in provitamin A and vitamin C. The Dena’ina found them also useful as food supplement for dogs and applied sap from the stem to wounds, believing it to have antiinflammatory properties.
Several researchers have studied this taxon. Heinrich Carl Haussknecht in the late 19th century and Peter H. Raven about a century later researched the phylogeny, systematics, and taxonomy of willowherbs. Peter Michaelis' studies of this genus paved the way for understanding of extranuclear inheritance in plants.

Species

The following species are recognised in the genus Epilobium:
File:Epilobium spp Sturm40.jpg|thumb|right|Top left: Epilobium alsinifolium
Bottom left: Epilobium anagallidifolium
Center: Epilobium tetragonum
File:Epilobium spp Sturm39.jpg|thumb|right|Left: Epilobium roseum
Right: Epilobium obscurum
  • Epilobium × abortivum
  • Epilobium × aggregatum
  • Epilobium aitchisonii
  • Epilobium algidum
  • Epilobium alpestre
  • Epilobium alsinifolium - chickweed willowherb
  • Epilobium alsinoides
  • Epilobium × amphibolum
  • Epilobium amurense
  • Epilobium anagallidifolium – alpine willowherb, pimpernel willowherb
  • Epilobium anatolicum
  • Epilobium anglicum
  • Epilobium angustifolium
  • Epilobium angustum
  • Epilobium arcticum – Arctic willowherb
  • Epilobium × argillaceum
  • Epilobium arvernense
  • Epilobium × aschersonianum
  • Epilobium astonii
  • Epilobium atlanticum
  • Epilobium australe
  • Epilobium barbeyanum
  • Epilobium billardiereanum – glabrous willowherb
  • Epilobium blinii
  • Epilobium × boissieri
  • Epilobium × borbasianum
  • Epilobium × brachiatum
  • Epilobium brachycarpum – tall willowherb, tall annual willowherb, tall fireweed, panicled willowherb
  • Epilobium brevifolium
  • Epilobium brevipes
  • Epilobium × brevipilum
  • Epilobium brevisquamatum
  • Epilobium × brunnatum
  • Epilobium brunnescens - New Zealand willowherb
  • Epilobium campestre – pygmy willowherb, smooth boisduvalia
  • Epilobium canum – Zauschneria, California-fuchsia, hummingbird flower, hummingbird trumpet
  • Epilobium capense
  • Epilobium × celakovskyanum
  • Epilobium × chateri
  • Epilobium chionanthum
  • Epilobium chitralense
  • Epilobium chlorifolium
  • Epilobium ciliatum – fringed willowherb, American willowherb
  • Epilobium clarkeanum
  • Epilobium clavatum – talus willowherb, clavatefruit willowherb
  • Epilobium cleistogamum – selfing willowherb
  • Epilobium cockayneanum
  • Epilobium colchicum
  • Epilobium collinum
  • Epilobium coloratum – purpleleaf willowherb
  • Epilobium confertifolium
  • Epilobium × confine
  • Epilobium × confusilobum
  • Epilobium confusum
  • Epilobium conjungens
  • Epilobium conspersum
  • Epilobium × cornubiense
  • Epilobium crassum
  • Epilobium curtisiae
  • Epilobium cylindricum
  • Epilobium × dacicum
  • Epilobium × dasycarpum
  • Epilobium davuricum – Daurian willowherb
  • Epilobium × decipiens
  • Epilobium densiflorum – denseflower willowherb, dense spike-primrose, dense boisduvalia
  • Epilobium densifolium
  • Epilobium densum – downy willowherb, stiff spike-primrose
  • Epilobium denticulatum
  • Epilobium detznerianum
  • Epilobium dodonaei
  • Epilobium duriaei
  • Epilobium elegans
  • Epilobium × erroneum
  • Epilobium × fallacinum
  • Epilobium fangii
  • Epilobium fastigiatoramosum
  • Epilobium fauriei
  • Epilobium × finitimum
  • Epilobium fleischeri
  • Epilobium × floridulum
  • Epilobium forbesii
  • Epilobium × fossicola
  • Epilobium fragile
  • Epilobium fugitivum
  • Epilobium gemmascens
  • Epilobium × gemmiferum
  • Epilobium × gerstlaueri
  • Epilobium glabellum – smooth spike-primrose
  • Epilobium glaberrimum – glaucous willowherb
  • Epilobium glaciale
  • Epilobium × glanduligerum
  • Epilobium glaucum
  • Epilobium × goerzii
  • Epilobium gouldii
  • Epilobium gracilipes
  • Epilobium × grenieri
  • Epilobium griffithianum
  • Epilobium gunnianum
  • Epilobium × gutteanum
  • Epilobium hallianum – glandular willowherb
  • Epilobium × haussknechtianum
  • Epilobium × haynaldianum
  • Epilobium × hectori-leveilleanum
  • Epilobium hectorii
  • Epilobium × heterocaulon
  • Epilobium hirsutum – great willowherb, great hairy willowherb, hairy willowherb, codlins-and-cream, apple-pie, cherry-pie
  • Epilobium hirtigerum
  • Epilobium hohuanense
  • Epilobium hooglandii
  • Epilobium hornemannii - Hornemann's willowherb
  • Epilobium howellii – Yuba Pass willowherb, subalpine fireweed
  • Epilobium × huteri
  • Epilobium indicum
  • Epilobium insulare
  • Epilobium × interjectum
  • Epilobium × intersitum
  • Epilobium × jinshaense
  • Epilobium karsteniae
  • Epilobium × keredjense
  • Epilobium kermodei
  • Epilobium keysseri
  • Epilobium kingdonii
  • Epilobium × kitcheneri
  • Epilobium komarovianum – bronzy willowherb
  • Epilobium komarovii
  • Epilobium korshinskyi
  • Epilobium × krausei
  • Epilobium lactiflorum – milkflower willowherb, whiteflower willowherb
  • Epilobium ladakhianum
  • Epilobium laestadii
  • Epilobium × lamotteanum
  • Epilobium lanceolatum - spear-leaved willowherb
  • Epilobium × langeanum
  • Epilobium × laschianum
  • Epilobium latifolium
  • Epilobium laxum
  • Epilobium leiophyllum
  • Epilobium leptocarpum – slenderfruit willowherb
  • Epilobium leptophyllum – bog willowherb, linear-leaved willowherb
  • Epilobium × limosum
  • Epilobium lipschitzii
  • Epilobium luteum – yellow willowherb
  • Epilobium macropus
  • Epilobium margaretiae
  • Epilobium × marshallianum
  • Epilobium matthewsii
  • Epilobium maysillesii
  • Epilobium melanocaulon
  • Epilobium × mentiens
  • Epilobium microphyllum
  • Epilobium minutiflorum
  • Epilobium minutum – chaparral willowherb, desert willowherb, smallflower willowherb
  • Epilobium mirabile – Olympic Mountain willowherb
  • Epilobium × montaniforme
  • Epilobium montanum – broad-leaved willowherb
  • Epilobium nanhualpinum
  • Epilobium nankotaizanense – Nankotaizan willowherb
  • Epilobium × neogradiense
  • Epilobium nerterioides
  • Epilobium nevadense – Nevada willowherb
  • Epilobium nivale
  • Epilobium nivium – Snow Mountain willowherb
  • Epilobium × novae-civitatis
  • Epilobium nummulariifolium
  • Epilobium nutans
  • Epilobium × nutantiflorum
  • Epilobium obcordatum – rockfringe willowherb
  • Epilobium × obscurescens
  • Epilobium obscurum – dwarf willowherb, short-fruited willowherb
  • Epilobium oreganum – Grants Pass willowherb, Oregon fireweed
  • Epilobium oregonense – Oregon willowherb
  • Epilobium × palatinum
  • Epilobium pallidiflorum
  • Epilobium pallidum – largeflower spike-primrose
  • Epilobium palustre – marsh willowherb
  • Epilobium pannosum
  • Epilobium parviflorum - small-flowered willowherb, hoary willowherb
  • Epilobium pedicellare
  • Epilobium pedunculare – rockery willowherb
  • Epilobium pengii
  • Epilobium × percollinum
  • Epilobium pernitens
  • Epilobium perpusillum
  • Epilobium × persicinum
  • Epilobium petraeum
  • Epilobium pictum
  • Epilobium platystigmatosum
  • Epilobium ponticum
  • Epilobium porphyrium
  • Epilobium × prionophylloides
  • Epilobium prostratum
  • Epilobium pseudorubescens
  • Epilobium × pseudotrigonum
  • Epilobium psilotum
  • Epilobium pubens
  • Epilobium puberulum
  • Epilobium × pulchrum
  • Epilobium purpuratum
  • Epilobium × purpureum
  • Epilobium pycnostachyum
  • Epilobium pyrricholophum
  • Epilobium ravenii – leafy willowherb, California willowherb
  • Epilobium rechingeri
  • Epilobium × reedii
  • Epilobium rhynchospermum
  • Epilobium rigidum – stiff willowherb, Siskiyou Mountains willowherb
  • Epilobium × rivulare
  • Epilobium × rivulicola
  • Epilobium roseum – pale willowherb
  • Epilobium rostratum
  • Epilobium rotundifolium
  • Epilobium royleanum
  • Epilobium rubromarginatum
  • Epilobium salignum
  • Epilobium sarmentaceum
  • Epilobium saximontanum – Rocky Mountain willowherb
  • Epilobium × schmidtianum
  • Epilobium × schulzeanum
  • Epilobium semiamplexicaule
  • Epilobium septentrionale – northern willowherb, Humboldt County fuchsia
  • Epilobium × sericeum
  • Epilobium sikkimense
  • Epilobium × similatum
  • Epilobium × simulatum
  • Epilobium sinense
  • Epilobium siskiyouense – Siskiyou willowherb, Siskiyou fireweed
  • Epilobium smithii
  • Epilobium speciosum
  • Epilobium spitianum
  • Epilobium staintonii
  • Epilobium stereophyllum
  • Epilobium stevenii
  • Epilobium stracheyanum
  • Epilobium subalgidum
  • Epilobium subcoriaceum
  • Epilobium subdentatum
  • Epilobium suffruticosum – shrubby willowherb
  • Epilobium × surreyanum
  • Epilobium taiwanianum
  • Epilobium tasmanicum
  • Epilobium tetragonum – square-stemmed willowherb
  • Epilobium thermophilum
  • Epilobium × thuringiacum
  • Epilobium tianschanicum
  • Epilobium tibetanum
  • Epilobium tonkinense
  • Epilobium torreyi – Torrey's willowherb, brook spike-primrose
  • Epilobium × treleaseanum
  • Epilobium trichophyllum
  • Epilobium tulinianum
  • Epilobium turkestanicum
  • Epilobium × udicola
  • Epilobium × uechtritzianum
  • Epilobium ulleungensis
  • Epilobium vernicosum
  • Epilobium vernonicum
  • Epilobium verticillatum
  • Epilobium × vicinum
  • Epilobium wallichianum
  • Epilobium × waterfallii
  • Epilobium wattianum
  • Epilobium williamsii
  • Epilobium willisii
  • Epilobium wilsonii
  • Epilobium × winkleri
  • Epilobium × wisconsinense – Wisconsin willowherb