See text Commonly known as hellebores (/ˈhɛləbɔːrz/), the Eurasian[2] genus Helleborus consists of approximately 20 species of herbaceous or evergreen perennial flowering plants in the family Ranunculaceae, within which it gave its name to the tribe of Helleboreae.

[5] The common name "hellebore" is first attested in 1300s; it originates, via Old French and Latin, ultimately from Ancient Greek: ἑλλέβορος, romanized: helléboros.

Ælfric of Eynsham seemed to assert that elleborus had no vernacular Old English translation; by the early 11th century, "wodewistle" was used to gloss the word, possibly referring to hemlock or similar.

[7] The flowers have five petal-like sepals surrounding a ring of small, cup-like nectaries which are actually petals modified to hold nectar.

[13] H. foetidus H. niger H. argutifolius H. lividus H. vesicarius H. thibetanus H. dumetorum H. purpurascens H. croaticus H. multifidus H. abruzzicus H. hercegovinus H. liguricus H. atrorubens H. viridis H. cyclophyllus H. torquatus H. orientalis H. odorus These four species have leaves on their flowering stems (in H. vesicarius the stems die back each year; it also has basal leaves).

Other species names (now considered invalid) may be encountered in older literature, including H. hyemalis, H. polychromus, H. ranunculinus, H. trifolius.

Hybridising (deliberate and accidental) between H. orientalis and several other closely related species and subspecies has vastly improved the colour-range of the flowers, which now extends from slate grey, near-black, deep purple and plum, through rich red and pinks to yellow, white and green.

H. × sternii, a cross between H. argutifolius and H. lividus, first exhibited in 1947, is named after the celebrated British plantsman Sir Frederick Stern.

As the population grows, the aphids eventually eat the remaining parts of the plant, such as older leaves, for food.

The spots continue to grow larger as the disease progresses, retaining an elliptical or circular shape and turning a dark brown or black color.

[30] The small black fruiting bodies which carry the spores, pycnidia, are formed in the dead cells of the leaf spots.

The fungus has an ideal habitat to spread and grow at the final growth site for hellebore plants, and if left untreated, the spores remain for many years.

The disease marks the leaves of the hellebores with black streaks, often following the veins of the leaf, and creating ring patterns.

The bacterial disease manifested on hellebore plants in the form of black leaf spots, necrosis petal, and stem lesions.

The symptoms were different from other leaf-spotting hellebore diseases, such as those caused by the fungus Coniothyrium and the bacteria Xanthomonas[33] The case in New Zealand is the only reported case of P. viridiflava infecting hellebores so far, but in other plants P. viridiflava has been reported to also induce symptoms such as leaf rot, leaf blotch, stem necrosis and blossom blight.

[33] Hellebores are widely grown in United States Department of Agriculture hardiness zones 5a to 8b gardens for decorative purposes.

They are particularly valued by gardeners for their winter and early spring flowering period; the plants are surprisingly frost-resistant and many are evergreen.

So is the 'stinking hellebore' or setterwort (H. foetidus), which has drooping clusters of small, pale green, bell-shaped flowers, often edged with maroon, which contrasts with its dark evergreen foliage.

[citation needed] The so-called Christmas rose (H. niger), a traditional cottage garden favourite, bears its pure white flowers (which often age to pink) in the depths of winter; large-flowered cultivars are available, as are pink-flowered and double-flowered selections.

This is typically caused by the ranunculin and protoanemonin found on the outside of the plant, including the leaves, stem, flower, and sap.

[36][37] The species historically known as "Black hellebore" cause tinnitus, vertigo, stupor, thirst, anaphylaxis, emesis (vomiting), catharsis, bradycardia (slowing of the heart rate), and finally, collapse and death from cardiac arrest.

[39] Although Helleborus niger (black hellebore) contains protoanemonin[40] or ranunculin,[41] which has an acrid taste and can cause burning of the eyes, mouth, and throat, oral ulceration, gastroenteritis, and hematemesis,[42] research in the 1970s showed that the roots of H. niger do not contain the cardiotoxic compounds helleborin, hellebrin, and helleborein that are responsible for the lethal reputation of "black hellebore".

It seems that earlier studies may have used a commercial preparation containing a mixture of material from other species such as Helleborus viridis, green hellebore.

[43] Although the latter plant is highly toxic, containing veratrine and the teratogens cyclopamine (which can cause the fatal birth defect of cyclopia) and jervine, it is believed to be the "hellebore" used by Hippocrates as a purgative.

[citation needed] Despite its toxicity, "black hellebore" was used by the Greek and Romans to treat paralysis, gout and other diseases, more particularly insanity.

[44] H. niger is commonly called the Christmas rose, due to an old legend that it sprouted in the snow from the tears of a young girl who had no gift to give the Christ Child in Bethlehem.

[45] In Greek mythology, Melampus of Pylos used hellebore to save the daughters of the king of Argos from a madness, induced by Dionysus, that caused them to run naked through the city, crying, weeping, and screaming.

[46] During the Siege of Kirrha in 585 BC, hellebore was reportedly used by the Greek besiegers to poison the city's water supply.