Everything about Euphorbia totally explained
Euphorbia is a
genus of
plants belonging to the
family Euphorbiaceae. Consisting of about 2160
species,
Euphorbia is one of the most diverse genera in the plant kingdom. Members of the family and genus are sometimes referred to
Spurges. The genus is primarily found in the
tropical and
subtropical regions of
Africa and the
Americas, but also in
temperate zones worldwide.
Succulent species originate mostly from Africa, the Americas and
Madagascar. There exists a wide range of
insular species, namely on the
Hawaiian Islands where spurges are collectively known as
ʻakoko
The
common name "spurge" derives from the
Middle English/
Old French espurge ("to purge"), due to the use of the plants sap as a
purgative.
The
botanical name Euphorbia derives from
Euphorbus, the
Greek physician of king
Juba II of
Numidia (52-50 BC - 23 AD). He is reported to have used a certain plant, possibly
Resin Spurge (
E. resinifera), as a
herbal remedy when the king suffered from a swollen belly.
Carolus Linnaeus assigned the name
Euphorbia to the entire genus in the physician's honor.
Juba II himself was a noted patron of the arts and sciences and sponsored several expeditions and biological research. He also was a notable author, writing several scholarly and popular scientific works such as treatises on natural history or a best-selling traveller's guide to
Arabia.
Euphorbia regisjubae (
King Juba's Euphorbia) was named to honor the king's contributions to natural history and his role in bringing the genus to notice.
Description
The plants are
annual or
perennial herbs, woody
shrubs or
trees with a caustic, poisonous milky sap (
latex). The
roots are fine or thick and fleshy or tuberous. Many species are more or less
succulent, thorny or unarmed. The main stem and mostly also the side arms of the succulent species are thick and fleshy, 15-91 cm (6-36 inches) tall. The deciduous
leaves are opposite, alternate or in whorls. In succulent species the leaves are mostly small and short-lived. The
stipules are mostly small, partly transformed into
spines or
glands, or missing.
Like all members of the family Euphorbiaceae, all spurges have unisexual
flowers. In
Euphorbia these are greatly reduced and grouped into
cyathia called
pseudanthia.
There are also (
monoecious) species with male and female flowers on the same plant and those (
dioecious) with male and female flowers occurring on different plants. It isn't unusual for the central cyathia of a
cyme to be purely male, and for lateral cyathia to carry both sexes. Sometimes young plants or those growing under unfavourable conditions are male only, and only produce female flowers in the cyathia with maturity or as growing conditions improve.
The
bracts are often leaf-like, sometimes brightly coloured and attractive, sometimes reduced to tiny scales.
The
fruits are three (rarely two) compartment
capsules, sometimes fleshy but almost always ripening to a woody container that then splits open (explosively). The
seeds are 4-angled, oval or spherical, and in some species have a
caruncle.
Xerophytes and succulents
In the genus
Euphorbia succulence in the species has often evolved divergently and to differing degrees. Sometimes it's difficult to decide, and it's a question of interpretation, whether or not a species is really succulent or "only"
xerophytic. In some cases, especially with
geophytes, plants closely related to the succulents are normal herbs. About 850 species are succulent in the strictest sense. If one includes slightly succulent and xerophytic species, this figure rises to about 1000, representing about 45% of all
Euphorbia species.
Toxicity
The latex (milky sap) of spurges acts as a deterrent for
herbivores as well as a wound healer. Usually it's white, but in rare cases (for example
E. abdelkuri) yellow. As it's under pressure, it runs out from the slightest wound and congeals within a few minutes of contact with the air. Among the component parts are many
di- or tri-terpen esters, which can vary in composition according to species, and in some cases the variant may be typical of that species. The terpen ester composition determines how caustic and irritating to the skin it is. In contact with mucous membranes (eyes, nose, mouth) the latex can produce extremely painful
inflammation. In experiments with animals it was found that the terpen ester
resiniferatoxin had an irritating effect 10,000 to 100,000 times stronger than
capsaicin, the "hot" substance found in
chillies. Several terpen esters are also known to be
carcinogenic.
Therefore handling spurges needs to be done with caution. Latex coming in contact with the skin should be washed off immediately and thoroughly. Partially or completely congealed latex is often no longer soluble in water, but can be removed with an emulsion (milk, hand-cream). With inflammation of a mucous membrane a doctor needs to be consulted. If cutting large succulent spurges in a greenhouse, it has been noticed that vapours from the latex spread and can cause severe irritation to the eyes and air passages several metres away. Caution is therefore required and for example ensure sufficient ventilation. Small children and domestic pets should never come into contact with spurges.
Uses
Several spurges are grown as garden plants, among them
Poinsettia (
E. pulcherrima) and the succulent
E. trigona.
E. pekinensis (Chinese: ; pinyin: dàjǐ) is used in
traditional Chinese medicine, where it's regarded as one of the
50 fundamental herbs. Several
Euphorbia species are used as food plants by the
larvae of some
Lepidoptera (butterflies and moths), including the
Giant Leopard Moth.
Euphorbias are used in natural medicine to heal cancer,leukemia and other virus caused illnesses.(esula, cyparissias, helioscopia and others)
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Systematics and taxonomy
According to recent studies of
DNA sequence data most of the smaller "satellite genera" around the huge genus
Euphorbia nest deep within the latter. Consequently these
taxa, namely the never generally accepted genus
Chamaesyce as well as the smaller genera
Cubanthus,
Elaeophorbia,
Endadenium,
Monadenium,
Synadenium
and
Pedilanthus were transferred to
Euphorbia. The entire
subtribe Euphorbiinae now consists solely of the genus
Euphorbia.
Selected species
See
List of Euphorbia species for complete list.
- Euphorbia albomarginata – Rattlesnake Weed, White-margined Sandmat
- Euphorbia amygdaloides – Wood Spurge
- Euphorbia bulbispina
- Euphorbia cyparissias – Cypress Spurge
- Euphorbia decidua
- Euphorbia elastica – (Mexican) Palo Amarillo
- Euphorbia esula – Leafy Spurge
- Euphorbia franckiana
- Euphorbia helioscopia – Sun Spurge
- Euphorbia heterophylla – Painted Euphorbia, Desert Poinsettia, (Mexican) Fireplant, Paint Leaf, Kaliko
- Euphorbia labatii
- Euphorbia lactea – Mottled Spurge, Frilled Fan, Elkhorn
- Euphorbia lathyris – Caper Spurge, Paper Spurge, Gopher Spurge, Gopher Plant, Mole Plant
- Euphorbia maculata – Spotted Spurge, Prostrate Spurge
- Euphorbia maritae
- Euphorbia milii – Crown-of-thorns, Christ Plant
- Euphorbia myrsinites – Myrtle Spurge, Creeping Spurge, donkey tail
- Euphorbia peplis – Purple Spurge
- Euphorbia peplus – Petty Spurge
- Euphorbia pulcherrima – Poinsettia, Mexican Flame Leaf, Christmas Star, Winter Rose, Noche Buena, Lalupatae, Pascua, Atatürk çiçeği (Turkish)
- Euphorbia resinifera – Resin Spurge
- Euphorbia tirucalli – Indian Tree Spurge, Milk Bush, Pencil Tree
- Euphorbia tithymaloides – Devil's Backbone, "Redbird cactus", cimora misha (Peru)
- Euphorbia virosa
Subgenera
The genus
Euphorbia is one of the largest and most complex genera of
flowering plants and several
botanists have made unsuccessfully attempts to subdivide the genus into numerous smaller genera. According to the recent
phylogenetic studies
,
Euphorbia can be divided into 4
subgenera, each containing several not yet sufficiently studied
sections and groups. Of these,
Esula is the most
basal.
Chamaesyce and
Euphorbia are probably
sister taxa but very closely related to
Rhizanthium. Extensive
xeromorph adaptations in all probability
evolved several times; it isn't known if the common ancestor of of the cactus-like
Rhizanthium and
Euphorbia lineages was xeromorphic - in which case a more normal morphology would have re-evolved namely in
Chamaesyce - or whether extensive xeromorphism is entirely
polyphyletic even to the level of the subgenera.
Esula
Image:Light green flowers.jpg|Wood SpurgeEuphorbia amygdaloides
Image:Zypressenwolfsmilch01.jpg|Cypress SpurgeEuphorbia cyparissias
Image:Euphorbia esula.jpeg|Leafy SpurgeEuphorbia esula
Image:Euphorbia myrsinites.JPG|Myrtle Spurge
Euphorbia myrsinites
Rhizanthium
Image:E ferox ies.jpg|Euphorbia ferox
Image:E flanaganii ies.jpg|Euphorbia flanaganii
Image:E meloformis valida ies.jpg|Euphorbia meloformis ssp. valida
Image:E obesa symmetrica ies.jpg|Euphorbia obesa ssp. symmetrica
Chamaesyce
Image:Chamaesyce cyathia.jpg|Euphorbia celastroides
Image:Euphorbiaheterophylla1web.jpg|Painted Euphorbia
Euphorbia heterophylla
Image:E pulcherrima ies.jpg|Poinsettia
Euphorbia pulcherrima
Image:E rivae ies.jpg|Euphorbia rivae
Euphorbia
Image:E actinoclada ies.jpg|Euphorbia actinoclada
Image:E attastoma attastoma ies.jpg|Euphorbia attastoma var. attastoma
Image:E confinalis rhodesica ies.jpg|Euphorbia confinalis ssp. rhodesica
Image:E lupulina ies.jpg|Euphorbia lupulina
Footnotes
Further Information
Get more info on 'Euphorbia'.
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