Artemisia (plant)

Artemisia ( ) is a large, diverse genus of plants belonging to the daisy family, Asteraceae, with almost 500 species. Common names for various species in the genus include mugwort, wormwood, and sagebrush.

Some botanists split the genus into several genera, but DNA analysis does not support the maintenance of the genera Crossostephium, Filifolium, Neopallasia, Seriphidium, and Sphaeromeria; three other segregate genera—Stilnolepis, Elachanthemum, and Kaschgaria—are maintained by this evidence. Occasionally, some of the species are called sages, causing confusion with the Salvia sages in the family Lamiaceae.

Artemisia comprises hardy herbaceous plants and shrubs, which are known for the powerful chemical constituents in their essential oils. Artemisia species grow in temperate climates of both hemispheres, usually in dry or semiarid habitats. Notable species include A. vulgaris (common mugwort), A. tridentata (big sagebrush), A. annua (sagewort), A. absinthium (wormwood), A. dracunculus (tarragon), A. abrotanum (southernwood), and A. herba-alba (white wormwood). The leaves of many species are covered with white hairs.

Most species have strong aromas and bitter tastes from terpenoids and sesquiterpene lactones, which discourage herbivory, and may have had a selective advantage. The small flowers are wind-pollinated. A more specific reference may be to Artemisia II of Caria, a botanist and medical researcher (also a queen and naval commander), who died in 350 BCE.

Classification

Classification of Artemisia is difficult. Part of this was due to research by Watson and colleagues, who found that the four subgenera were not monophyletic except for Dracunculus, after analyzing and matching the internal transcribed spacers of nuclear ribosomal DNA from many Seriphidium and Artemisia species, and the related genera Arctanthemum and Dendranthema. The authors concluded that inflorescence morphology is not alone reliable for categorizing the genus or some subgenera, as qualities that previously demarcated them (such as homogamous, discoid, ray-less inflorescences) seemed to have undergone paralleled evolution up to seven times. In some classifications, they have previously been considered part of the genus or subgenus Seriphidium, although recent studies have contested this lineage to Old World species. Much of the debate surrounding Tridentatae is phytogeographic, thus habitat and geography are frequently cited when understanding the evolution of this endemic North American subgenus. Evolutionary cycles of wet and dry climates encouraged "diploid and polyploid races which are morphologically similar if not indistinguishable" (McArthur 598).

Autopolyploidy among plants is not uncommon, however Tridentatae exhibits a remarkable amount of chromosomal differences at the population level, rather than the taxon level. This contributes to the difficulty in determining Tridentatae's phylogeny. The subgenus' relative homogeneity within ploidies has enabled it to habitually hybridize and backcross, resulting in a high degree of genetic variation at the population level rather than the taxon level. For instance, some articles suggest that to be monophyletic, section Tridentatae should exclude Artemisia bigelovii and A. palmeri. These results were supported by extensive chloroplast DNA (cpDNA) and nrDNA sequencing which departed from prior morphological, anatomical, and behavioral data.

Traditional lineages within Tridentatae were proposed on the basis of leaf morphology, habitat preference, and the ability to leaf-sprout, among other morphological and behavioral characteristics. and there is some ribosomal molecular evidence of a "Tridentatae core" group for the subgenus. In 2011, Garcia and colleagues proposed enlarging Tridentatae and organized it into the sections Tridentatae, Nebulosae, and Filifoliae based on previous research establishing relationships via ribosomal and nuclear DNA.

Artemisia tridentata
Artemisia cana
Artemisia nova
Artemisia rigida
Artemisia arbuscula
Artemisia longiloba
Artemisia tripartita
Artemisia pygmaea
Artemisia rothrockii

Section Tridentatae includes above species with the exception of A. longiloba, which is treated as a subspecies of A. arbuscula. Section Nebulae includes A. californica, A. nesiotica, and A. filifolia.

Seriphidium

The Old World species which different classifications put into the genus or subgenus Seriphidium consist of about 125 species native to Europe and temperate Asia, with the largest number of species in Central Asia. Some classifications, such as that of the Flora of North America, exclude any New World plants from Seriphidium. Old World Seriphidium, with 125 species native to Europe and temperate Asia, was a previous classification of Seriphidium. North American or "New World" Seriphidium and Old World Seriphidium. North American Seriphidium were later placed into Tridentatae Rydb due to geographical distribution, growth habit, and karyotypic and chemotaxonomic similarities (such as presence of certain terpenols).

Subgenus Dracunculus

One group which is well-supported by molecular data is subgenus Dracunculus. It consists of 80 species found in both North America and Eurasia, This study places Dracunculus as one of the more recent subgenera within Artemisia, situating A. salisoides more basally on the tree, with North American endemic groups such as the sagebrushes having derived on the other end of a split from a common ancestor with Dracunculus. Formerly proposed genera Mausolea, Neopallasia and Turaniphytum are now argued to be within the subgenus Dracunculus due to ribosomal and chloroplast DNA evidence, with further species resolved as sister groups to Dracunculus due to phytochemical relationships.

Species

thumb|[[Artemisia abrotanum]]

thumb|[[Artemisia absinthium]]

thumb|[[Artemisia annua]]

thumb|[[Artemisia californica (California sagebrush) leaves]]

thumb|[[Artemisia mauiensis (Maui wormwood)]]

thumb|[[Artemisia nilagirica (Nilagiri wormwood)]]

thumb|[[Artemisia pontica (Roman wormwood)]]

thumb|[[Artemisia pycnocephala (beach sagewort) flowers]]

, Plants of the World Online accepted almost 500 species. Below are named some of the most notable Artemisia species:

Artemisia abrotanum L. – southernwood, southern wormwood, slovenwood, abrotanum, old-man, lad's love
Artemisia absinthium L. – grand wormwood, absinthium
Artemisia afra Jacq. ex Willd. – African wormwood, African sagebrush
Artemisia alba Turra – camphor southernwood
Artemisia aleutica Hultén – Aleutian wormwood
Artemisia annua L. – annual wormwood, sweet sagewort, sweet Annie
Artemisia arborescens L. – tree wormwood
Artemisia arbuscula Nutt. – little sagebrush, low Sagebrush, black sage
Artemisia arenaria DC.
Artemisia argyi H.Lév. & Vaniot – Chinese mugwort
Artemisia austriaca Jacq.
Artemisia bhutanica Grierson & Spring.
Artemisia biennis Willd. – biennial sagewort, biennial wormwood
Artemisia bigelovii A.Gray – Bigelow sage, Bigelow sagebrush
Artemisia caerulescens L.
Artemisia californica Less. – coastal sagebrush, California sagebrush
Artemisia campestris L. – field wormwood, sand wormwood
Artemisia cana Pursh – silver sagebrush
Artemisia capillaris Thunb. – capillary wormwood, yin-chen wormwood
Artemisia carruthii Wood ex Carruth. – Carruth sagewort, Carruth's sagebrush
Artemisia chamaemelifolia Vill.
Artemisia cina O.Berg & C.F.Schmidt – santonica, Levant wormseed
Artemisia douglasiana Bess. – Douglas' mugwort, Douglas' sagewort, northwest mugwort
Artemisia dracunculus L. – tarragon, silky wormwood
Artemisia filifolia Torr. – sand sagebrush, sand-sage, silvery wormwood
Artemisia franserioides Greene – ragweed sagebrush
Artemisia frigida Willd. – fringed sagebrush, fringed-sage, prairie sagewort, estafiata
Artemisia furcata Bieb. – forked wormwood
Artemisia glacialis L. – glacier wormwood, alpine mugwort
Artemisia glauca Pall. ex Willd.
Artemisia globularia Cham. ex Bess. – purple wormwood
Artemisia gmelinii Webb ex Stechmann – Gmelin's wormwood, Russian wormwood
Artemisia gorgonum Webb
Artemisia herba-alba Asso – white wormwood
Artemisia inculta Delile
Artemisia indica Willd. – Indian wormwood
Artemisia integrifolia L.
Artemisia japonica Thunb. – otoko yomogi
Artemisia laciniata Willd. – Siberian wormwood
Artemisia lactiflora Wall. ex DC. – white mugwort
Artemisia longifolia Nutt. – longleaf sagebrush, longleaf wormwood
Artemisia ludoviciana Nutt. – gray sagewort, prairie sage, white sagebrush, Louisiana-sage, western-sage
Artemisia maritima L. – sea wormwood, absinthe de mer
Artemisia marschalliana Spreng.
Artemisia michauxiana Bess. – Michaux sagebrush, Michaux's wormwood, lemon sagewort
Artemisia nesiotica Raven – island sagebrush
Artemisia norvegica Fr. – Norwegian mugwort, alpine sagewort
Artemisia nova A.Nels. – black sagebrush, small sagebrush
Artemisia olchonensis Leonova
Artemisia orientalixizangensis Y.R.Ling & Humphries
Artemisia packardiae J.Grimes & Ertter – Packard's wormwood, Succor Creek sagebrush
Artemisia pallens Wall
Artemisia palmeri A.Gray – San Diego sagewort
Artemisia papposa S.F.Blake & Cronq. – Owyhee sage, Owyhee sagebrush
Artemisia pedatifida Nutt. – birdfoot sagebrush, matted sagewort
Artemisia pontica L. – Roman wormwood, green-ginger
Artemisia porteri Cronq. – Porter's wormwood, Porter mugwort
Artemisia princeps Pamp. – Japanese mugwort, yomogi
Artemisia pycnocephala (Less.) DC. – beach wormwood, coastal sagewort
Artemisia pygmaea A.Gray – pygmy sagebrush
Artemisia rigida (Nutt.) A.Gray – scabland sagebrush
Artemisia rothrockii A.Gray – timberline sagebrush
Artemisia rupestris L. – rock wormwood
Artemisia schmidtiana Maxim. – angel's hair
Artemisia scoparia Waldst. & Kit. – redstem wormwood, yin-chen wormwood
Artemisia senjavinensis Bess. – arctic wormwood
Artemisia serrata Nutt. – sawtooth wormwood
Artemisia sieversiana Willd. – sieversian wormwood
Artemisia spiciformis K.Koch
Artemisia spinescens D.C.Eaton – budsage [syn. Picrothamnus desertorum]
Artemisia stelleriana Bess. – hoary mugwort, oldwoman, Dusty Miller, beach wormwood
Artemisia suksdorfii Piper – coastal wormwood, Suksdorf sagewort
Artemisia thuscula Cav.
Artemisia tilesii Ledeb. – Tilesius' wormwood, Aleutian mugwort
Artemisia tridentata Nutt. – big sagebrush, blue sage, black sage, basin sagebrush, common sagebrush
Artemisia tripartita Rydb. – threetip sagebrush
Artemisia umbelliformis Lam. – Alps wormwood, alpine wormwood
Artemisia verlotiorum Lamotte – Chinese wormwood
Artemisia viridis Willd. ex DC.
Artemisia vulgaris L. – mugwort, felonherb, green-ginger, common wormwood

Formerly placed here

Centipeda minima (L.) A.Braun & Asch. (as A. minima L.)
Eupatorium capillifolium (Lam.) Small (as A. capillifolia Lam.)
Filifolium sibiricum (L.) Kitam. (as A. sibirica (L.) Maxim.)
Grangea maderaspatana (L.) Poir. (as A. maderaspatana L.)
Matricaria discoidea DC. (as A. matricarioides auct.)

Ecology

Artemisia species are found on every continent except Antarctica, and have become part of many ecosystems around the world as a result. Below is currently a partial view of the importance of Artemisia species in ecosystems around the world.

North America

In North America, several species of Artemisia have become important parts of local environments, with wide adaptability. Artemisia papposa described by S.F.Blake & Arthur Cronquist can grow in the harsh, dry expanses of alkali flats, but also adapts to meadowlands.

Sagebrushes like A. papposa (of the Tridenteae subgenus) in general are found in the north and southwest areas of the North American continent. In the Intermountain West, in a habitat known as Sagebrush Steppe, A. tridentata, A. tripartite, and A. arbuscula grow alongside various grasses and species of bitter bush, creating an important environment for mule deer, pygmy rabbits, antelopes, and the sage grouse. Understanding the phylogenetic relationships among the sagebrushes has been helpful in understanding the relationships among these plants and their environments, as well as learning more about how these plants formed these communities over long stretches of time. with sagebrush shrubs living as long as 200 years (though potentially typically 88), this particular combination of Artemisia with other flora form an enduring habitat. Destabilization of the vegetation creates higher risk of fires, causing concern among the local conservation and wildlife groups.

This is particularly true of Artemisia vulgaris, known as "common mugwort", in North America, where it was introduced by European colonists and settlers in the 1600s, when Jesuit priests and other colonizers may have first brought the herb for ointments and teas and likely also let into port cities via ballast dumping. Artemisia vulgaris will grow in dense groups and out-compete other plants in an area, in part due to its ability to grow on poorly enriched soils. Disturbed habitats, cities and roadsides or parking lots can easily become a field of A. vulgaris, which is the Artemisia species designated as invasive by New York State.

Cultivation and uses

Historical uses

Historically, Artemisia species were used in the attempted cure of various medical ailments, particularly related to women's health. In the Middle Ages, Artemisia sp. were regarded as herbs of significant medical power, and described as "the most important master against all exhaustions". By the Renaissance, Artemisia sp. (particularly A. absinthium) was used particularly in the cure of digestive ailments, though the use of species such as A. vulgaris in women's health still persisted. Historian John Scarborough (1940-2022) argued that Dioscorides' discussion of Artemisia sp. was an adaptation of folklore medicine that was commonly used in Asia Minor and Thrace. Learned medicine in the Middle Ages was largely based on humoral theory, which ascribed certain properties to herbs based on their use in heating/cooling and wetting/drying the body. A. vulgaris was described by the second century physician Galen (c.129-216 AD) as having warming and drying effects, which recommended it to the treatment of urological diseases. The continued use of Artemisia as an abortifacient was described by twelfth-century women's health texts in the Trotula. This use was further integrated into university teaching by Johannes II Platearius (active 1120-1150) at the medical school of Salerno, who proscribed a "wine of the decoction of artemisia" as a cure to blocked menstrual flow.

thumb|Gart Artemisia Text

Artemisia sp. continued to be used in women's health into the 16th century, and was described by Johann Wonnecke von Kaub in Gart der Gesundheit as the "mother herb", for use in "women's sickness". This continued in the English medical tradition as well, with mugwort (likely A. vulgaris) being described as a "an herb appropriated to the female sex" for use in "bringing down the menses" by the English physician Nicholas Culpeper's 1653 Complete Herbal.

Historical medicinal uses

In Anglo-Saxon medicine, Artemisia vulgaris (mugwort) and A. pontica were described as treatments for soreness, pains and aches. A. vulgaris and A. absinthium were used to repel midges (Old English mucgwyrt seems to be derived from mycg ), fleas and moths, intestinal worms, and in brewing (mugwort beer, mugwort wine) as a remedy against hangovers and nightmares.

Modern uses

The aromatic leaves of some species are used for flavouring. Most species have an extremely bitter taste. A. dracunculus (tarragon) is widely used as a culinary herb, particularly important in French cuisine.

Artemisia absinthium is used to make the highly potent spirit absinthe. Malört also contains wormwood. The aperitif vermouth is a wine flavored with aromatic herbs, but originally with wormwood.

Artemisia arborescens (tree wormwood, or sheeba in Arabic) is an aromatic herb indigenous to the Middle East used in tea, usually with mint.

A few species are grown as ornamental plants, the fine-textured ones used for clipped bordering. All grow best in free-draining sandy soil, unfertilized, and in full sun.

The largest collection of living Artemisia species, subspecies and cultivars is held in the National Collection of Artemisia in Sidmouth, Devon, UK, which holds about 400 taxa. The National Collection scheme is administered by Plant Heritage (formerly National Council for Conservation of Plants and Gardens, NCCPG) in the British Isles.

Medicinal uses

Artemisinin (from Artemisia annua) and derivatives are a group of compounds used to treat malaria. Treatments containing an artemisinin derivative (artemisinin-combination therapies) are now standard treatment worldwide for malaria caused by Plasmodium falciparum.

Tu Youyou received the 2015 Nobel Prize in Physiology or Medicine for her discovery of the semisynthetic derivatives. She conducted research on traditional Chinese medicine and potential contributions to cures for malaria, on the basis of folk medicine and ancient Chinese texts. From reviewing ancient Chinese texts, they found that the compound artemisinin was optimally extracted at lower temperatures, as high temperature water poured over sweet wormwood leaves destroyed essential treatment properties.

The World Health Organization does not support the promotion or use of Artemisia plant material in any form for the prevention or treatment of malaria. They note that the plant form of medication has several problems. These include a lack of consistent artemisinin content, the content being low enough that recurrence of malaria often occurs, that the use of the plant may contribute to widespread artemisinin resistance, and that the plant form is not effective in malaria prevention.