Symphytum

Symphytum is a genus of flowering plants in the borage family, Boraginaceae, known by the common name comfrey (pronounced Template:IPAc-en, from the Latin confervere to 'heal' or literally to 'boil together', referring to uses in ancient traditional medicine).

Symphytum is native to northern temperate regions of Europe and Asia, with a wide introduced distribution on both continents as well as the Americas.<ref name = powo/><ref name=WFO/> There are 59 recognized species.<ref name="WFO">Template:Cite web</ref> More than 150 species have been cataloged by botanists.<ref>Template:Cite web</ref> Some species and hybrids, particularly S. officinale, Symphytum grandiflorum, and S. × uplandicum, are used in gardening and herbal medicine. Species in the genus Symphytum are different from Andersonglossum virginianum, known as wild comfrey, which is another member of the borage family.<ref name="usda">Template:PLANTS</ref>

Species

27 species are accepted.<ref name = powo/>

• Symphytum aintabicum Template:Small
• Symphytum anatolicum Template:Small
• Symphytum asperum Template:Small – prickly comfrey, rough comfrey
• Symphytum × bicknellii Template:Small
• Symphytum bornmuelleri Template:Small
• Symphytum brachycalyx Template:Small – Palestine comfrey
• Symphytum bulbosum – bulbous comfrey
• Symphytum carpaticum Template:Small
• Symphytum caucasicum – Caucasian comfrey
• Symphytum circinale Template:Small
• Symphytum cordatum Template:Small
• Symphytum creticum Template:Small
• Symphytum davisii Template:Small
• Symphytum × ferrariense Template:Small
• Symphytum grandiflorum Template:Small – creeping comfrey
• Symphytum gussonei Template:Small
• Symphytum hajastanum Template:Small
• Symphytum ibiricum Template:Small – Iberian comfrey<ref>Template:Cite web</ref>
• Symphytum kurdicum Template:Small
• Symphytum longisetum Template:Small
• Symphytum × mosquense Template:Small
• Symphytum officinale Template:Small – comfrey
• Symphytum orientale Template:Small – white comfrey
• Symphytum ottomanum Template:Small
• Symphytum podcumicum Template:Small
• Symphytum pseudobulbosum Template:Small
• Symphytum savvalense Template:Small
• Symphytum sylvaticum Template:Small
• Symphytum tauricum Template:Small – Crimean comfrey
• Symphytum tuberosum Template:Small – tuberous comfrey
• Symphytum × ullepitschii Template:Small
• Symphytum × uplandicum Template:Small (S. asperum × S. officinale, synonym: S. peregrinum) – Russian comfrey, healing herb, blackwort, bruisewort, wallwort, gum plant

Russian comfrey (Symphytum × uplandicum)

Flowers of Russian comfrey

• Symphytum × wettsteinii Template:Small

Cultivation

The Russian comfrey 'Bocking 4' and 'Bocking 14' cultivars were developed during the 1950s by Lawrence D. Hills, the founder of the Henry Doubleday Research Association (the organic gardening organization itself named after Henry Doubleday, who first introduced Russian comfrey into Britain in the nineteenth century) following trials at Bocking, Essex.<ref>Template:Cite book</ref>

Propagation

Bocking 4 and 14 are sterile, and therefore will not set seed (one of its advantages over other cultivars as it will not spread out of control); thus, it is propagated from root cuttings. The gardener can produce "offsets" from mature, strongly growing plants by driving a spade horizontally through the leaf clumps about Template:Cvt below the soil surface. This removes the crown, which can then be split into pieces. The original plant will quickly recover, and each piece can be replanted with the growing points just below the soil surface, and will quickly grow into new plants. Offsets can also be purchased by mail order from specialist nurseries in order to initially build up a stock of plants.<ref name="teynor">Template:Cite web</ref>

Phytochemistry, folk medicine, and toxicity

Folk medicine names for comfrey include knitbone, boneset, and the derivation of its Latin name Symphytum (from the Greek symphytis, meaning growing together of bones, and phyton, a plant<ref name=HyamPank95p486>Template:Cite book</ref>Template:Source needed, referring to its ancient uses. Similarly, the common French name is Template:Lang, meaning to weld together. The tradition in different cultures and languages suggest a common belief in its usefulness for mending bones.

Comfrey contains mixed phytochemicals in varying amounts, including allantoin, mucilage, saponins, tannins, pyrrolizidine alkaloids, and inulin, among others.<ref name="drugs">Template:Cite web</ref> Pyrrolizidine alkaloids are responsible for comfrey's liver toxicity,<ref>Template:Cite journal</ref> which is associated with consuming this plant or its extracts.<ref name="drugs" /> In modern herbalism, comfrey is most commonly used topically.<ref name="drugs" /><ref>Template:Cite journal</ref><ref>Template:Cite journal</ref>

In 2001, the United States Food and Drug Administration issued a ban of comfrey products marketed for internal use, and a warning label for those intended for external use.<ref>Template:Cite web</ref> Use of comfrey is particularly discouraged during pregnancy and lactation, in infants, and in people with liver, kidney, or vascular diseases.<ref name="drugs" /><ref>Template:Cite journal</ref>