2000 species in 100 genera are of cosmopolitan distribution.
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In a study of Plants and Animals of the Santa Barbara Backcountry it was noted that "[the plant's] dense growth makes a natural barrier to hiking in the chaparral. It sometimes forms almost pure stands called a chamissal. It's easier to force your way through chamise than manzanita or ceanothus, but the persistent dry flowers and seed husks mix with your sweat and get down your shirt and become very irritating."
The plant should not be confused with Larrea tridentata Cov. (fam. Zygophyllaceae), an unrelated plant also known as greasewood.
Both Wren (1975) and Flück & Jaspersen-Schib (1976) refer to the external use of a preparation of this plant in folk medicine as a vulnerary.
The fruit is covered with hooks hence the first colloquial name. A decoction of the root and leaf is used as a blistering agent in Africa (Watt & Breyer-Brandwijk 1962). The plant was incriminated in Oppenheim's meadow dermatitis (O'Donovan 1942) but has, at the most, only slight photosensitising activity (Van Dijk & Berrens 1964, Van Dijk 1964) suggesting that irritation rather than photodermatitis can result from contact.
Cooper (1902) described three cases of acute dermatitis of the hands, wrists, face, and thighs in gardeners who had clipped extensive Cotoneaster microphylla [sic] hedges. He noted that the leaves of the plant were thickly covered with filiform white hairs with a sharply pointed free extremity. These, he believed, were responsible [in part] for the dermatitis. The eruptions, which had an erythematous and urticarial appearance, resolved after 10–14 days. Intense irritation was the worst feature of these cases. The head gardener later reported that further slight cases occurred in spite of the men wearing gloves and keeping their sleeves turned down.
Prosser White (1934) seemingly referred to this report but the reference he provided to Cooper's article was, unfortunately, incorrect.
Crataegus pubescens forms a large bush or small tree armed with long thorns (Dahlgren & Standley 1944).
Duke-Elder & MacFaul (1972b) noted that the hairs from the fruit can cause nodose conjunctivitis. They were probably referring to rose hips, not haws. The thorns are particularly toxic to the eye. Corneal scratches led to loss of useful vision in 88 cases in 132 such accidents in Ireland (Smith 1940). The thorns are less injurious than those of Prunus spinosa.
A mucilage surrounding the seeds and used in pharmaceutical preparations is considered to be a known allergen and is therefore removed from certain brand-name cosmetics (Anon 1973).
A female cannery-worker developed severe hand eczema. Angelica was at first suspected to be the cause but a patch test to wet quince hair (tomentum) which she cleaned from the fruits produced a positive reaction; dry quince tomentum produced no reaction. A patch test to zinc chlorate used in the vats also produced a positive reaction (Stauffer 1931).
The plant is a source of salicylaldehyde from which salicylic acid and in turn aspirin were/was originally synthesised. The word aspirin was constructed as follows: a for acetyl, spir for Spirsäure [= salicylic acid] in turn named from the genus Spiraea, and in as a popular suffix for drugs of those times (Mueller & Scheidt 1994).
Spiraea or possibly Astilbe (Spirea) were noted as available in a commercial extract for patch-testing (McCord 1962). There do not appear to be any reports of dermatitis from the plant.
15 species are found in North America, Chile and from Eurasia to southern India. Several species are cultivated for their edible fruit.
A gardener developed eczema from contact with strawberries and from eating the fruit (Gougerot et al. 1931). A confectionery factory worker (and one of 102 controls) showed a positive patch test reaction to a natural strawberry flavouring (Hegyi 1971).
40 species are found in northern and southern temperate regions and in the Arctic. Members of this genus have hooked fruits which attach themselves to animals (Howes 1974).
The seeds are covered with bristles which fix themselves on any passing object (Wren 1975). Flück & Jaspersen-Schib (1976) notes that a preparation of the dried rhizome or herb has been used in folk medicine as an application to wounds.
According to Mabberley (1987), 25 species are found in northern temperate regions. Members of this genus were at one time considered to belong to the genus Pyrus L.
Many are widely grown commercially and as ornamental trees and bushes for their fruit (apples, crab apples, cider apples).
This "species" name represents an aggregate of over 1000 cultivars derived from a number of species through extensive hybridisation. Parentage is believed to include M. dasyphylla Borkh., M. praecox Borkh., M. pumila Mill., and possibly M. sylvestris Mill. (Mabberley 1987). Accordingly, it is probably appropriate to discard the species name domestica in favour of cultivar names where known (for example Malus cv Cox's Orange Pippin, Malus cv Golden Delicious, etc.) when referring to apples by their scientific name.
Women employed in cleaning apples and pears (Pyrus communis L.) developed dermatitis and fissured eczema of the hands and paronychia (Szego 1966). Schwartz et al. (1957) reviewed dermatitis in the fruit-canning industry. Erhart (1925) reported dermatitis from fruit. Apple peel was found to be responsible for a case of periocular eczema (Hazen 1944).
2-Chloro-6-phenylphenol (Stopmold™) is a fungicide which has been used on fruit. It has caused sensitisation dermatitis and its vapours are irritating to the eyes (Scott 1949). Sodium bisulfite used as an antioxidant to prevent discoloration of fruit and vegetables caused allergic contact dermatitis in a salad-maker; a patch test with sodium bisulfite 10% aqueous produced a positive reaction, negative in controls (Epstein 1970). Ethoxyquin, used to prevent "apple scald" during storage, produced dermatitis in apple-packers (Wood and Fulton 1972).
The fruit is commonly eaten when partially decomposed ("bletted"). Genner and Bonnevie (1938) refer to a report of dermatitis from the leaves of dwarf medlar.
The genus Mespilus L. is monotypic. The medlar is a small tree which is found from south-eastern Europe to Central Asia.
60 species are found from the Himalayas to Japan and Sumatra and in North America.
The pickled fruits, if eaten in excess, make the mouth and tongue rough and crack open (Smith 1969).
The herb boiled in vinegar with honey and alum has been used in folk medicine as a gargle for sore mouths and ulcerated gums, and to fasten loose teeth. If the herb is steeped in strong white wine vinegar, the resulting solution has been used externally to remove freckles, spots and pimples from the face (Wren 1975). Flück & Jaspersen-Schib (1976) and Stuart (1979) note that a decoction of the plant has been applied to wounds.
A lotion prepared from the roots of this plant has been used in folk medicine as a wash for ulcers and old sores; the fluid extract also acts as a styptic when applied to cuts and wounds (Wren 1975). Flück & Jaspersen-Schib (1976) and Stuart (1979) refer to the traditional use of an infusion prepared from the dried rhizome as a lotion for inflammation of the mouth, throat or vagina; and also to the use of a decoction as a soothing application for minor burns and sunburn. Stuart (1979) also states that a lotion prepared from the plant is used externally to treat haemorrhoids and frostbite, and that the plant promotes epithelization but cautions that prolonged contact with the skin should be avoided as it may cause scarring.
According to Stuart (1979), the root yields a red dye that appears to be identical with a substance known as ratanhia-red present in the root bark of Peruvian rhatany (Krameria triandra Ruíz & Pavón, fam. Krameriaceae). Interestingly, both tormentil and Peruvian rhatany also seem to share the same traditional use as an astringent mouthwash for fixing loose teeth. Indeed, Stuart (1979) records that tormentil was at one time considered a less costly alternative to Peruvian rhatany.
A preparation of the root has been used in folk medicine as a gargle for sore mouths and ulcerated gums, and to fasten loose teeth (Wren 1975). Flück & Jaspersen-Schib (1976) also refers to this use, noting in addition that a decoction of the plant has been used to bathe wounds.
This and the other three species in the genus Prinsepia Royle, which occur naturally from India to north-eastern China, form thorny deciduous shrubs (Mabberley 2017). They are occasionally found in cultivation as ornamentals (Hunt 1968/70).
Hausen (1970) cites Brezina (1912) for an injurious effect of the wood.
In 289 women employed in making cherry preserves, cases of dermatitis, conjunctivitis, and respiratory disorders were found to be due to exposure to sulfur dioxide fumes. Skin lesions were constantly present in those affected (Fimiani et al. 1963).
Sorters, shellers and packers of prunellas and sloes (Prunus spinosa) can be attacked by a mites that infest the dried fruits (Fuhs 1923, cited by Prosser White 1934, Rasch, cited by O'Donovan 1921). Moulds on prunes (the dried fruits of the plum) can cause dermatitis (Prosser White 1934). Spitzer (1927) reported dermatitis from prunes. Belisario (1948) referred to similar findings.
This species yields oil of bitter almond. Perfumes, colognes and toilet water containing the oil can cause dermatitis in hypersensitive individuals (Tulipan 1938). Greenberg and Lester (1954) and Klarmann (1958) also list oil of bitter almond as capable of producing dermatitis.
The seeds are the source of oil of sweet almond (Jordan almond) (Budavari 1996). Almond oil was considered to be an allergen for atopic individuals (Coca et al. 1931). Oil of almond and a major constituent of the oil, benzaldehyde, are considered to be known allergens and have therefore been removed from certain brand-name cosmetics (Anon 1973). A report of contact sensitivity to almond flour but not to any other kind of flour was noted by Prosser White (1934), probably from Molesworth (1930).
Massage to the skin with cherry laurel oil produced dermatitis (Rayer 1835).
Peaches have often caused dermatitis both among those who pick them and because of the sharp fuzz on many varieties and among those who can them (Schwartz et al. 1957). The canners develop dermatitis from the juice of the peach which contains much sugar and is hygroscopic and irritating to the skin (Schwartz et al. 1957). The "fur" on the skin of peaches was considered to cause erythema and papules on the face, neck, forearms and elbow flexures of workers in the fruit canning industry (Foreign Letter 1929).
Positive Type I hypersensitivity skin reactions to juice of fresh peaches and melons (Cucumis, fam. Cucurbitaceae) were reported by Tuft and Blumstein (1942). Dry fruit extracts produced negative reactions.
The fuzz of the peach acts as a mechanical irritant; later, true sensitisation of the skin may appear (Weber 1949).
This species forms a very spiny shrub (Polunin 1969) with a long-standing reputation for inflicting thorn injuries that take longer than expected to heal: "The thorns have something of a poisonous nature in the autumn" (Withering 1787); "From some effects which I have repeatedly observed to follow the prick of the thorns, I have reason to believe there is something poisonous in them …" (Withering 1801). Wimmer (1926) published a drawing of the spine-tipped twigs.
Buhr (1960) reported that thorn injuries of the hands from this plant in 10 patients, most of whom were agricultural workers, required nearly four times longer outpatient treatment than did thorn injuries from hawthorn (Crataegus monogyna Jacq.) or from gooseberry (Ribes uva-crispa L., fam. Grossulariaceae).
Uteau & Bouget (1928) held that the fly-infested putrefying bodies of birds and small animals spitted on the thorns by shrikes accounted for the inflammation that occurs after blackthorn pricks. These authors also noted that they had seen two cases of thorn-induced tetanus. However, Buhr (1960) recovered no unusual bacteria or other pathogens either from his patients or from cultures of blackthorns obtained from hedges. But, he did note also that one of his 10 patients developed tetanus of moderate severity. Other case reports include a horseman who unknowingly sustained a deeply penetrating thorn injury whilst leaping a hedge and who became increasingly debilitated until the thorn was eventually discovered 6 years later and removed (Wardell 1851); a 9-year-old schoolboy in whom the broken tip of a thorn produced a profuse foreign body reaction (Latham 1960); and a 61-year-old housewife who developed dyspnoea and a generalised vesicular rash, infected in places, after scratching her arm on a blackthorn (Cashmore 1960). It would appear that the tip of the rough long brittle thorn of the blackthorn snaps off more readily in the skin than does the short needle-sharp point of hawthorn.
Dermatitis from sloes is noted under Prunus domestica.
This is a genus of about 10 species of shrubs or small trees usually with thorny branches. Three species occur naturally in southeastern Europe and seven in Asia (Gu & Spongberg 2003).
McCord (1962) noted the commercial availability of an oleoresin extract of [an unspecified species of] Pyracantha for patch testing. There appear to be no reports of dermatitis from members of this genus.
Dermatitis from pears is noted under Malus domestica. In addition, women working with pears developed a painful oedematous swelling with hyperkeratosis, fissuring and immobility of the flexed finger (Szego 1966).
The fruit is soaked in oil and used to darken grey or red hair (Smith 1969).
The powdered bark yields quillaja saponin which lathers with water; it is sternutatory when dispersed in the air (Budavari 1996). A splash of a solution of Quillaja saponin into the eye of a chemist caused irritation (Bakker 1940). The bark contains also contains calcium oxalate crystals.
250 species are found in northern temperate regions and on tropical mountains.
In 1645, Sir Kenelme Digby wrote: " … Lady Hennage (who was of the bed-chamber to the late Queen Elizabeth) … had her cheeke blistered by laying a rose upon it whiles shee was asleepe, to try if her antipathy against that flower were so great as she used to pretend" (Macalpine & Hunter 1956). Malten (1972) thinks this is the "very oldest report on contact investigations and incidentally carried out with psychological precautions".
Harrison (1906) included roses — especially in America — in a list of plants etc., which may cause dermatitis. Contact dermatitis from rose or positive patch test reactions to the plant were reported by Niedziella (1930), Curtis (1960), and Hjorth (1968). Dorsey (1962) received a report of dermatitis caused by tea roses, but provided no detail.
A woman, aged 66 years, showed a positive patch test to the petal of a red rose; patch tests to a green leaf from the red rose, and to the petal and green leaf from a white rose were negative. The patient was also contact sensitive to Iris (Hjorth 1961).
Contact dermatitis was observed by van Ketel (1974) in four individuals, two culturists of roses and two florists especially handling roses (Rosa sorina). The dermatitis was traced to an organophosphorus anti-mildew agent Plondrel (O,O-diethyl-phthalimido phosphothioate). This material is very stable and leaves a residue in the leaves and petals. Five days after spraying with Plondrel 9.2 ppm were found in the leaves, 0.45 ppm in the petals, by gas liquid chromatography. In two patients he could not exclude contact sensitivity to the rose itself. He classified contact dermatitis from the plants as arising from:
Sulfur, used on roses, produced dermatitis in a gardener (Wilkinson 1975). Malathion, an insecticide often used on roses, can cause contact dermatitis (Milby and Epstein 1964). Contact dermatitis from pesticides was reported by Sicherer (1965) and reviewed by Cronin and Wilkinson (1973).
A rose thorn that penetrated the palm produced an osteolytic lesion simulating a bone tumour (Maylahn 1952).
Kedes et al. (1964) reported a case of sporotrichosis from the thorn of a rose bush. Its victim was a gardener who often fell asleep at work after drinking wine.
In 1565, Botallus reported an individual who, after smelling roses, would have a violent attack of sneezing, rhinorrhoea and headache (Biederman 1937).
The pollen is a rare cause of hayfever (Wodehouse 1971). The scent of roses causes some persons to sneeze.
Widely named also as Rosa x damascena Mill., the Damask rose is now considered to be a hybrid of triparental origin: DNA analyses point to the presumed original maternal parent being Rosa moschata Herrm., this having been pollinated with Rosa gallica L. pollen. The resultant hybrid ovule was then seemingly pollinated with pollen from Rosa fedschenkoana Regel [now considered by some authorities to be a synonym of Rosa webbiana Wall. ex Royle] to produce the common ancestor of the four oldest Damask varieties, namely the so-called summer Damasks 'Kazanlik' and 'York and Lancaster', and the so-called autumn Damasks 'Quatre Saisons' and 'Quatre Saison Blanc Mousseux'. The variety 'Kazanlik' has been most abundantly planted for rose attar [also called attar or otto of rose, essence of rose, or rose oil] production (Iwata et al. 2000).
Oil of Rose derived from this and / or other Rosa species / varieties has been reported to cause dermatitis in hypersensitive individuals (Zundel 1936, Flandin et al. 1937, Tulipan 1938, Tzanck et al. 1938, 1939). Geraniol is contained in Oil of Rose. 2/15 patients contact sensitive to balsam of Peru (from Myroxylon balsamum Harms, fam. Leguminosae) showed a positive patch test reaction to geraniol (Hjorth 1961).
250 species are of cosmopolitan distribution.
Some, including Rubus fruticosus L. (blackberry), are capable of producing mechanical injury by their thorns.
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According to Stuart (1979), the root decoction is an excellent haemostatic and can be used on all cuts and wounds. Wren (1975) also refers to this property.
Although the genus Sarcopoterium Spach is considered to be monotypic, some authorities would place the taxon on the genus Poterium L. The plant, which grows naturally in Italy and the eastern Mediterranean, forms a low rounded shrub with stiff much-interwoven spiny branches (Polunin 1969). Mabberley (2017), referring to Poterium spinosum L., noted that the plant is very common near Jerusalem and was possibly the species from which the crown of thorns of Jesus Christ was produced — see also Paliurus spina-christi Mill., Ziziphus spina-christi Willd., and Euphorbia milii Des Moul.
The fruits are used to make jellies, etc., and in brandy (Germany), in vodka (Russia) and as a substitute for coffee. The leaves are used as a tea and as an adulterant of tea (Camellia) (Usher 1974).
Sorbic acid may be obtained from the berries of this plant, where it occurs as the lactone, called parasorbic acid. Sorbic acid may cause slight skin irritation. Sorbic acid in industrial accidents has given rise to a necrotic lesion of the corneal epithelium which has healed rapidly (Duke-Elder & MacFaul 1972b). 0.5% of 200 eczematous patients showed positive patch test reactions to sorbic acid (Schorr 1971). 0.6% of 736 eczematous patients showed positive patch test reactions to sorbic acid (Klaschka and Beiersdorff 1965). 0.3% of 1,489 patients with skin diseases showed positive patch test reactions to sorbic acid (Hjorth and Trolle-Lassen 1963). At that time (1961) sorbic acid was not used as a preservative in dermatological creams in Denmark. The only other exposure they were able to trace was plants or berries known to contain sorbic acid. Guinea pigs could be sensitised to sorbic acid (Klaschka and Beiersdorff 1965).