Erythranthe


Erythranthe, the monkey-flowers and musk-flowers, is a diverse plant genus with more than 120 members in the family Phrymaceae. Erythranthe was originally described as a separate genus, then generally regarded as a section within the genus Mimulus, and recently returned to generic rank. Mimulus sect. Diplacus was segregated from Mimulus as a separate genus at the same time. Mimulus remains as a small genus of eastern North America and the Southern Hemisphere. Molecular data show Erythranthe and Diplacus to be distinct evolutionary lines that are distinct from Mimulus as strictly defined, although this nomenclature is controversial.
Member species are usually annuals or herbaceous perennials. Flowers are red, pink, or yellow, often in various combinations. A large number of the Erythranthe species grow in moist to wet soils with some growing even in shallow water. They are not very drought resistant, but many of the species now classified as Diplacus are. Species are found at elevations from oceanside to high mountains as well as a wide variety of climates, though most prefer wet areas such as riverbanks.
The largest concentration of species is in western North America, but species are found elsewhere in the United States and Canada, as well as from Mexico to Chile and eastern Asia. Pollination is mostly by either bees or hummingbirds. Member species are widely cultivated and are subject to several pests and diseases. Several species are listed as threatened by the International Union for Conservation of Nature.

Description

Erythranthe is a highly diverse genus with the characteristics unifying the various species being axile placentation and long pedicels. Other characteristics of species can vary widely, especially between the sections, and even within some sections. Some species of Erythranthe are annuals and some are perennials. Flowers are red, pink, purple, or yellow, often in various combinations and shades of those colors. Some species produce copious amounts of aromatic compounds, giving them a musky odor. Erythranthe is used as food by the larvae of some Lepidoptera species, such as the mouse moth, as a main part of their diet.
Within the section Erythranthe, stems and leaves range from glabrous to hirsute, and are generally glandular. Leaves can be oblong, elliptical, or oval, with small tooths. Fruiting pedicels are longer than calyces. Calyces have sharp, definite angles and flat sides. Corollas are deciduous, relatively large, and strongly red to purplish, magentarose, pink, or white, rarely yellow.
Erythranthe guttata is the most widespread of the genus Erythranthe and its characteristics are fairly representative of the genus. E. guttata is tall with disproportionately large long, tubular flowers. Leaves are opposite and oval, long. The species as strictly defined is perennial and spreads with stolons or rhizomes. The stem may be erect or recumbent. In the latter form, roots may develop at lower leaf nodes. Sometimes dwarfed, it may be hairless or have some hairs. Leaves are opposite, round to oval, usually coarsely and irregularly toothed or lobed. The bright yellow flowers are born on a raceme, most often with five or more flowers. The calyx has five lobes that are much shorter than the flower. Each flower has bilateral symmetry and has two lips. The upper lip usually has two lobes; the lower, three. The lower lip may have one large to many small red to reddish brown spots. The opening to the flower is hairy. The fruit is a two-valved capsule long, containing many seeds.
Erythranthe alsinoides is similar to several species found in the Pacific Northwest. It is an annual herb that blooms from April–June with a preference for shady and moist dense habitats. The plant is hairy to slightly hairy and grows from tall. The stems are often reddish. The leaves are opposite and have a few prominent upper veins. Blades are long. The petiole is about the same length. The flowers are yellow with reddish-brown spots, usually on the lower lip, and the upper and lower lips have fused, growing. Each flower is attached by a pedicel. The fruits are capsules.

Etymology and taxonomy

The derivation of Erythranthe is from Greek ἐρυθρός, red, with ἄνθος, flower. They are called monkey-flowers because some species have flowers shaped like a monkey's face. The widely used generic name, Latin mimus meaning "mimic actor", from the Greek mimos meaning "imitator" also alludes to the fancied monkey resemblance. The stem of Erythranthe can be either smooth or hairy, and this is known in a few species to be a trait determined by a simple allelic difference. At least E. lewisii is known to possess "flypaper-type" traps and is apparently protocarnivorous, supplementing its nutrients with small insects. Variations in color largely reflect concentrations of anthocyanins. The species that are subshrubs with woody stems were originally placed in the section Diplacus, and this was subsequently made a separate genus. Diplacus is clearly derived from within Mimulus, broadly defined, and was not usually considered to be a separate genus.
The French botanist Édouard Spach established Erythranthe as a separate genus with just the type species Erythranthe cardinalis. In 1885, American botanist Edward Lee Greene classified Erythranthe as a section of Mimulus while adding E. lewisii and E. parishii. In the 2012 restructuring of Mimulus by Barker et al., based largely upon DNA evidence, seven species were left in Mimulus as strictly defined; Erythranthe was greatly enlarged to include 111 species, based upon axile placentation and long pedicels, 46 placed into Diplacus, two placed in Uvedalia, and one each placed in Elacholoma, Mimetanthe, and Thyridia. All of the American genera are still referred to as "monkey-flowers".
Views on the evolutionary position of the monkey-flower species have changed. It was long considered to be in the family Scrophulariaceae, but is now placed in Phyrmaceae, primarily on the basis of DNA evidence. The genus Phryma, for which the family is named, is considerably different in morphology from all of the monkey-flowers.
Attempts at crossing species, whether from different sections or within the same section, of Erythranthe are not always successful. E. peregrina is an example of a successful naturally occurring hybrid that not only arose independently in two different locations, but is also a rare example of evolutionary recent allopolyploidization, complete chromosomal inheritance.
Charles Darwin's 1876 study of inbreeding depression and self-fertility in South American species was a progenitor for the study of Erythranthe biology. The genus has become a model system "for studies of evolutionary and ecological functional genomics... ... contains a wide array of phenotypic, ecological and genomic diversity." Species under intense genomic study are mostly among the section Simiolus and the section Erythranthe. The genome sequence of E. guttata was released in late spring, 2007.
Many issues remain in Erythranthe taxonomy. E. guttata is highly complex, with many variations apparently reflecting differences in geographic environment and elevation. Molecular geneticists regard the species broadly as including both perennial and annual populations, but there is rationale for treating this complex as several distinct species. The perennials and annuals differ as groups from each other by an inversion sequence on chromosome 8. Evidence tentatively indicates that the perennials evolved from annual ancestors, although some evidence has been interpreted to indicate that E. nasuta evolved from E. guttata in central California between 500,000 and 200,000 years ago and since then become primarily a self-pollinator. Relationships among the apparently closely related E. tilingii, E. minor, and E. caespitosa are not clearly understood. Some currently recognized species may be just variants of other species: E. arenicola, E. brachystylis, E. regni. Chromosomal issues may affect the classification of some species: E. corallina, E. guttata, E. nasuta, E. tilingii, and E. utahensis.

Species

Species listed alphabetically

, Plants of the World Online accepted the following species and hybrids:
  • Erythranthe acutidens G.L.Nesom
  • Erythranthe alsinoides G.L.Nesom & N.S.Fraga – chickweed monkey-flower
  • Erythranthe ampliata G.L.Nesom
  • Erythranthe androsacea N.S.Fraga – rockjasmine monkey-flower
  • Erythranthe arenaria G.L.Nesom
  • Erythranthe arenicola G.L.Nesom
  • Erythranthe arvensis G.L.Nesom
  • Erythranthe austrolatidens G.L.Nesom
  • Erythranthe barbata N.S.Fraga
  • Erythranthe bhutanica G.L.Nesom –
  • Erythranthe bicolor G.L.Nesom & N.S.Fraga – yellow and white monkey-flower
  • Erythranthe bodinieri G.L.Nesom –
  • Erythranthe brachystylis G.L.Nesom
  • Erythranthe bracteosa G.L.Nesom –
  • Erythranthe breviflora G.L.Nesom –
  • Erythranthe brevinasuta G.L.Nesom
  • Erythranthe breweri G.L.Nesom & N.S.Fraga – Brewer's monkey-flower
  • Erythranthe bridgesii G.L.Nesom –
  • Erythranthe caespitosa G.L.Nesom
  • Erythranthe calcicola N.S.Fraga
  • Erythranthe calciphila G.L.Nesom
  • Erythranthe cardinalis Spach – scarlet monkey-flower
  • Erythranthe carsonensis N.S.Fraga – Carson Valley monkey-flower
  • Erythranthe charlestonensis G.L.Nesom
  • Erythranthe chinatiensis G.L.Nesom
  • Erythranthe cinnabarina G.L.Nesom
  • Erythranthe corallina G.L.Nesom
  • Erythranthe cordata G.L.Nesom
  • Erythranthe cuprea G.L.Nesom – Flor de cobre
  • Erythranthe decora G.L.Nesom
  • Erythranthe dentata G.L.Nesom – toothleaf monkey-flower, coastal monkey-flower
  • Erythranthe dentiloba G.L.Nesom
  • Erythranthe depressa G.L.Nesom
  • Erythranthe diffusa N.S.Fraga
  • Erythranthe diminuens G.L.Nesom –
  • Erythranthe discolor N.S.Fraga
  • Erythranthe eastwoodiae G.L.Nesom & N.S.Fraga
  • Erythranthe erubescens G.L.Nesom
  • Erythranthe exigua G.L.Nesom & N.S.Fraga – San Bernardino Mountains monkey-flower
  • Erythranthe filicaulis G.L.Nesom & N.S.Fraga – slender-stemmed monkey-flower
  • Erythranthe filicifolia G.L.Nesom
  • Erythranthe flammea G.L.Nesom
  • Erythranthe floribunda G.L.Nesom – manyflowered monkey-flower
  • Erythranthe gemmipara G.L.Nesom & N.S.Fraga – Rocky Mountain monkey-flower
  • Erythranthe geniculata G.L.Nesom
  • Erythranthe geyeri G.L.Nesom
  • Erythranthe glabrata G.L.Nesom – roundleaf monkey-flower
  • Erythranthe glaucescens G.L.Nesom – shieldbract monkey-flower
  • Erythranthe gracilipes N.S.Fraga – slenderstalk monkey-flower
  • Erythranthe grandis G.L.Nesom
  • Erythranthe grayi G.L.Nesom
  • Erythranthe guttata G.L.Nesom – common large monkey-flower, common monkey-flower, stream monkey-flower, seep monkey-flower
  • Erythranthe hallii G.L.Nesom
  • Erythranthe hardhamiae N.S.Fraga
  • Erythranthe howaldiae G.L.Nesom
  • Erythranthe hymenophylla G.L.Nesom
  • Erythranthe inamoena G.L.Nesom
  • Erythranthe inconspicua G.L.Nesom –
  • Erythranthe inflata G.L.Nesom –
  • Erythranthe inflatula G.L.Nesom
  • Erythranthe jungermannioides G.L.Nesom
  • Erythranthe karakormiana G.L.Nesom –
  • Erythranthe laciniata G.L.Nesom
  • Erythranthe lagunensis G.L.Nesom
  • Erythranthe latidens G.L.Nesom – broadtooth monkey-flower
  • Erythranthe lewisii G.L.Nesom & N.S.Fraga – great purple monkey-flower, Lewis' monkey-flower
  • Erythranthe linearifolia G.L.Nesom & N.S.Fraga
  • Erythranthe lutea G.L.Nesom – yellow monkey-flower, monkey musk, blotched monkey-flower, and blood-drop-emlets
  • Erythranthe madrensis G.L.Nesom
  • Erythranthe marmorata G.L.Nesom
  • Erythranthe michiganensis G.L.Nesom – Michigan monkey-flower
  • Erythranthe microphylla G.L.Nesom
  • Erythranthe minima J.M.Watson & A.R.Flores–
  • Erythranthe minor G.L.Nesom
  • Erythranthe montioides N.S.Fraga – montia-like monkey-flower
  • Erythranthe moschata G.L.Nesom –
  • Erythranthe naiandina G.L.Nesom
  • Erythranthe nasuta G.L.Nesom
  • Erythranthe nelsonii G.L.Nesom & N.S.Fraga – In 2014 Nesom lists as a synonym of Erythranthe verbenacea
  • Erythranthe nepalensis G.L.Nesom
  • Erythranthe norrisii G.L.Nesom
  • Erythranthe nudata G.L.Nesom
  • Erythranthe orizabae G.L.Nesom –
  • Erythranthe pallens G.L.Nesom
  • Erythranthe palmeri N.S.Fraga – Palmer's monkey-flower
  • Erythranthe pardalis G.L.Nesom
  • Erythranthe parishii G.L.Nesom & N.S.Fraga – Parish's monkey-flower
  • Erythranthe parvula G.L.Nesom
  • Erythranthe patula G.L.Nesom
  • Erythranthe pennellii G.L.Nesom
  • Erythranthe percaulis G.L.Nesom
  • Erythranthe platyphylla G.L.Nesom –
  • Erythranthe plotocalyx G.L.Nesom
  • Erythranthe primuloides G.L.Nesom & N.S.Fraga – primrose monkey-flower
  • Erythranthe procera G.L.Nesom –
  • Erythranthe ptilota G.L.Nesom
  • Erythranthe pulsiferae G.L.Nesom – candelabrum monkey-flower
  • Erythranthe purpurea N.S.Fraga – little purple monkey-flower
  • Erythranthe regni G.L.Nesom
  • Erythranthe rhodopetra N.S.Fraga
  • Erythranthe rubella N.S.Fraga – little redstem monkey-flower
  • Erythranthe rupestris G.L.Nesom & N.S.Fraga
  • Erythranthe scouleri G.L.Nesom
  • Erythranthe serpentinicola D.J.Keil
  • Erythranthe sessilifolia G.L.Nesom –
  • Erythranthe shevockii N.S.Fraga – Kelso Creek monkey-flower
  • Erythranthe sierrae N.S.Fraga
  • Erythranthe sinoalba G.L.Nesom –
  • Erythranthe sookensis B.G. Benedict – newly discovered 2012, originally named M. sookensis
  • Erythranthe stolonifera G.L.Nesom –
  • Erythranthe suksdorfii N.S.Fraga – Suksdorf's monkey-flower and miniature monkey-flower
  • Erythranthe szechuanensis G.L.Nesom –
  • Erythranthe taylorii G.L.Nesom
  • Erythranthe tenella G.L.Nesom –
  • Erythranthe thermalis G.L.Nesom –
  • Erythranthe tibetica G.L.Nesom –
  • Erythranthe tilingii G.L.Nesom – large mountain monkey-flower, Tiling's monkey-flower
  • Erythranthe trinitiensis G.L.Nesom
  • Erythranthe unimaculata G.L.Nesom
  • Erythranthe utahensis G.L.Nesom
  • Erythranthe verbenacea G.L.Nesom & N.S.Fraga
  • Erythranthe veronicifolia G.L.Nesom
  • Erythranthe visibilis G.L.Nesom
  • Erythranthe washingtonensis G.L.Nesom
  • Erythranthe willisii G.L.Nesom
Hybrids:
  • Erythranthe × burnetii Silverside
  • Erythranthe × hybrida Silverside
  • Erythranthe × maculosa Mabb.
  • Erythranthe × robertsii G.L.Nesom, syn. Erythranthe peregrina G.L.Nesom – newly discovered 2012, originally named ''M. peregrinus''