Lotus (genus)

Lotus (genus)
Lotus, a latinization of Greek lōtos, is a genus of flowering plants that includes most bird's-foot trefoils (also known as bacon-and-eggs) and deervetches and contains many dozens of species distributed in the eastern hemisphere, including Africa, Europe, western, southern, and eastern Asia, and Australia and New Guinea. Depending on the taxonomic authority, roughly between 70 and 150 are accepted. Lotus is a genus of legumes and its members are adapted to a wide range of habitats, from coastal environments to high elevations.
The genus Lotus is currently undergoing extensive taxonomic revision. Species native to the Americas have been moved into other genera, such as Acmispon and Hosackia, as in the second edition of The Jepson Manual.
The aquatic plant commonly known as the Indian or sacred lotus is Nelumbo nucifera, a species not closely related to Lotus.
Description
Most species have leaves with five leaflets; two of these are at the extreme base of the leaf, with the other three at the tip of a naked midrib. This gives the appearance of a pair of large stipules below a "petiole" bearing a trefoil of three leaflets – in fact, the true stipules are minute, soon falling or withering. Some species have pinnate leaves with up to 15 leaflets. The flowers are in clusters of three to ten together at the apex of a stem with some basal leafy bracts; they are pea-flower shaped, usually vivid yellow, but occasionally orange or red. The seeds develop in three or four straight, strongly diverging pods, which together make a shape reminiscent of the diverging toes of a small bird, leading to the common name "bird's-foot".
Taxonomy
The genus Lotus is taxonomically complex. It has at times been divided into subgenera and split into segregate genera, but with no consistent consensus. P.H. Raven in 1971 is said to have been the first to suggest that the "New World" (American) and "Old World" (African and Eurasian) species did not belong in the same genus. A molecular phylogenetic study in 2000 based on nuclear ribosomal ITS sequences confirmed this view. The New World species have been divided between the genera Hosackia s.str., Ottleya, Acmispon and Syrmatium. A 2006 study, primarily concerned with Old World Lotus species and hence with limited sampling of the American genera, found that they were all monophyletic. The study also supported the view that Dorycnium and Tetragonolobus are not distinct from Lotus at the generic level. More species were added to the 2006 results in 2008, but did not alter the broad conclusions reached before. Clades were identified within Lotus s.str., some of which were significantly different from the sections into which the genus had been divided. However, resolution was incomplete. The results of the analysis were presented in terms of clades and complexes.
Species
The following species are recognised in the genus Lotus:
Lotus aduncus
Lotus aegaeus
Lotus alianus
Lotus alpinus - alpine bird's-foot-trefoil
Lotus anfractuosus
Lotus angustissimus – slender bird's-foot trefoil
Lotus arabicus
Lotus arenarius
Lotus argyrodes
Lotus arinagensis
Lotus assakensis
Lotus australis – austral trefoil
Lotus axilliflorus
Lotus becquetii
Lotus benoistii
Lotus berthelotii – Canary Islands trefoil
Lotus biflorus
Lotus borbasii
Lotus broussonetii
Lotus brunneri
Lotus burttii
Lotus callis-viridis
Lotus campylocladus
Lotus carpetanus
Lotus castellanus
Lotus chazaliei
Lotus compactus
Lotus conimbricensis
Lotus conjugatus
Lotus corniculatus – common bird's-foot trefoil, bird's-foot deervetch
Lotus creticus
Lotus cruentus
Lotus cytisoides
Lotus × davyae
Lotus discolor
Lotus divaricatus
Lotus dorycnium
Lotus drepanocarpus
Lotus dumetorum
Lotus edulis
Lotus emeroides
Lotus eremiticus
Lotus eriophthalmus
Lotus frondosus
Lotus fulgurans
Lotus garcinii
Lotus gebelia
Lotus germanicus
Lotus glacialis
Lotus glareosus
Lotus glaucus
Lotus glinoides
Lotus goetzei
Lotus gomerythus
Lotus graecus
Lotus halophilus
Lotus hebecarpus
Lotus hebranicus
Lotus herbaceus
Lotus hirsutus
Lotus holosericeus
Lotus jacobaeus
Lotus japonicus
Lotus jolyi
Lotus jordanii
Lotus krylovii
Lotus kunkelii
Lotus lalambensis
Lotus lancerottensis
Lotus lanuginosus
Lotus laricus
Lotus latidentatus
Lotus lebrunii
Lotus longisiliquosus
Lotus lourdes-santiagoi
Lotus loweanus
Lotus macranthus
Lotus maculatus
Lotus maritimus
Lotus maroccanus
Lotus mascaensis
Lotus × medioximus
Lotus michauxianus
Lotus × minoricensis
Lotus miyakojimae
Lotus mlanjeanus
Lotus mollis
Lotus namulensis
Lotus nubicus
Lotus oliveirae
Lotus ononopsis
Lotus ornithopodioides
Lotus palustris
Lotus parviflorus – smallflower bird's-foot trefoil, smallflower trefoil
Lotus peczoricus
Lotus pedunculatus – greater bird's-foot trefoil, marsh bird's-foot trefoil, large bird's-foot trefoil, big trefoil
Lotus peregrinus
Lotus polyphyllos
Lotus pseudocreticus
Lotus purpureus
Lotus pyranthus
Lotus quinatus
Lotus rechingeri
Lotus rectus
Lotus requienii
Lotus robsonii
Lotus sanguineus
Lotus schoelleri
Lotus sessilifolius
Lotus simoneae
Lotus spartioides
Lotus spectabilis
Lotus stepposus
Lotus strictus
Lotus subbiflorus – hairy bird's-foot trefoil
Lotus subdigitatus
Lotus taitungensis
Lotus tenellus (including Lotus leptophyllus (Lowe) K.Larsen)
Lotus tenuis – narrowleaf trefoil, slender trefoil, creeping trefoil, or prostrate trefoil
Lotus tetragonolobus
Lotus tetraphyllus
Lotus tibesticus
Lotus torulosus
Lotus × ucrainicus
Lotus villicarpus
Lotus weilleri
Lotus wildii
Lotus zemmouriensis
Species placed elsewhere
Lotus aboriginus = Hosackia rosea
Lotus argophyllus = Acmispon argophyllus
Lotus argyraeus = Acmispon argyraeus
Lotus benthamii = Acmispon cytisoides
Lotus crassifolius = Hosackia crassifolia
Lotus dendroideus = Acmispon dendroideus
Lotus denticulatus = Acmispon denticulatus
Lotus grandiflorus = Acmispon grandiflorus
Lotus hamatus = Acmispon micranthus
Lotus haydonii = Acmispon haydonii
Lotus heermannii = Acmispon heermannii
Lotus humistratus = Acmispon brachycarpus
Lotus incanus = Hosackia incana
Lotus junceus = Acmispon junceus
Lotus mearnsii = Acmispon mearnsii
Lotus micranthus = Acmispon parviflorus
Lotus nevadensis = Acmispon decumbens
Lotus nuttallianus = Acmispon prostratus
Lotus oblongifolius = Hosackia oblongifolia
Lotus pinnatus = Hosackia pinnata
Lotus procumbens = Acmispon procumbens
Lotus rubriflorus = Acmispon rubriflorus
Lotus salsuginosus = Acmispon maritimus
Lotus stipularis = Hosackia stipularis
Lotus wrightii = Ottleya wrightii
Uses and ecology
Lotus species are used as food plants by the larvae of some Lepidoptera species. Several species are cultivated for forage, including L. corniculatus, L. glaber, and L. pedunculatus. They can produce toxic cyanogenic glycosides which can be potentially toxic to livestock, but also produce tannins, which are a beneficial anti-bloating compound.
Species in this genus can fix nitrogen from the air courtesy of their root nodules, making them useful as a cover crop. The nodulating symbionts are Bradyrhizobium and Mesorhizobium bacteria. Scientific research for crop improvement and understanding the general biology of the genus is focused on L. japonicus, which is currently the subject of a full genome sequencing project, and is considered a model organism.
Some species, such as L. berthelotii from the Canary Islands, are grown as ornamental plants. L. corniculatus is an invasive species in some regions of North America and Australia.
References
External links
Lotus species names
Fabaceae genera
Taxa named by Carl Linnaeus