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Brachyglottis - Centaurea

(Daisy or Sunflower family)


Brachyglottis greyi B.Nord.
[syn. Senecio greyi Hook.f.]
Daisy Bush, Ragwort

It should be noted that according to the Royal Horticultural Society Horticultural Database, a plant purchased through the nursery trade as Brachyglottis greyi (or Senecio greyi, Brachyglottis laxifolia, or Senecio laxifolius) may actually be Brachyglottis cv. Sunshine (syn. Senecio cv. Sunshine), one of the so-called Dunedin Group hybrids originally derived [acc. to Wikipedia] from Senecio greyi Hook.f., Senecio laxifolius Buchanan, and Senecio compactus Kirk.

[Further information available but not yet included in database]

Brachyglottis hectori B.Nord.
[syn. Senecio hectori Buchanan]

Senecio hectori was reported to cause skin irritation in New Zealand (Maiden 1918a).

Brachyglottis repanda J.R.Forst. & G.Forst.
Bushman's Friend, Pukapuka, Rangiora Tree, Wharangi

The wood is injurious to wood-workers because of its alkaloid content (Aston 1923, Briggs 1946). Honey produced from the nectar of this plant is poisonous. The Maoris never take wild honey when the rangiora is in blossom (Aston 1923).

Buphthalmum L.

Novak & Kolinsky (1960) reported dermatitis from a plant in this genus.

Calea urticaefolia DC.
[syn. Caleacte urticifolia R.Br.]

This species is used in Salvadorian folk medicine as a topical bacteriocide. Juanislamin and other germacranolide sesquiterpene lactones, bearing the structural features associated with contact allergenicity in this class of compounds (Mitchell & Dupuis 1971), have been isolated from this plant (Borges del Castillo et al. 1981).

Calendula L.

Twenty or thirty species are found in the Mediterranean region and east to Iran. The genus is classified in the tribe Calenduleae.

Calendula as a constituent of a proprietary remedy produced contact dermatitis in four individuals who had plant dermatitis (Underwood & Gaul 1948). Hjorth (1965) reported one positive patch test reaction from many tests with Calendula.

Calendula officinalis L.
Pot Marigold

This species is commonly grown for its ornamental flowers. The plant yields an oil that may be used in perfumery (Arctander 1960). Irritancy has been ascribed both to the plant itself and to a tincture made from it (Behl et al. 1966). A positive patch test reaction to an extract of this species was observed by Hausen (1981b) in a florist who was sensitised to Tanacetum parthenium Sch.Bip. However, Hausen & Osmundsen (1983) observed a negative reaction in an investigation of a similarly sensitised male hobby gardener.

Callistephus chinensis Nees
[syn. Aster chinensis L.]
China Aster

The cultivated asters are occasional causes of pollinosis (Wodehouse 1971). The genus is monotypic and is classified in the tribe Astereae. The plant grows naturally in China and Japan.

Calomeria amaranthoides Vent.
[syns Humea elegans Sm., Agathomeris amaranthoides de Launay]
Crimson Shower, Incense Plant, Plume Bush, Rose-Coloured Humea

This is a shrub with aromatic foliage that is found naturally in southern Australia, but which may be found in cultivation as a greenhouse ornamental. The dermatological literature refers to the plant by its older name Humea elegans.

The plant emits a scent when bruised. A woman who rubbed the leaves on her veil for their scent developed vesicular dermatitis of the nose and cheeks (Hearnden 1902). Maiden (1913) noted that the foliage of this plant can elicit eczema and that several cases of eye irritation had been reported in those working with the plant or standing on the leeward side of a clump when a breeze was blowing. Patch tests to the leaves were positive in two gardeners who developed dermatitis from contact with the plant (Cronin 1968, Rook 1970). Control tests with the plant to exclude irritancy were carried out on four subjects by Rook (1970).

Calotis cuneifolia R.Br.

This species produces small, "almost invisible" burs which are annoying if they get into blankets and are very troublesome to the feet of dogs (Maiden 1895).

Cardopatium corymbosum DC.

α-Terthienyl, a phototoxic thiophene (see Tagetes L. below), has been isolated from the roots of this species (Sprio et al. 1972, Selva et al. 1978).

Carduus L.

The genus is classified in the tribe Cynareae. One hundred species are found in Europe, the Mediterranean region, and in Asia. These plants are thistles bearing sharp spines on the leaves and flowers. The genus is very close to Cirsium Mill.

Carduus nutans L.

Wimmer (1926) refers to the spine-tips of the leaves of this species as a possible cause of mechanical injury.

Carlina acaulis L.
Alpine Carline Thistle, Weather Thistle, Silver Thistle, Dwarf Thistle

This species, and others in the genus, has spiny leaves.

Carthamus tinctorius L.
[syns Carduus tinctorius Ehrh., Carthamus glaber Burm.f.]
False Saffron, Saffron Thistle, Safflower

This plant, which is occasionally grown as a hardy annual, has spiny leaves. The seeds are the source of safflower oil. An orange dye is obtained from the flowers. It occurs as a mixture of yellow (principally hydroxysafflor yellow A) and red (principally carthamin) pigments.

The florets have have been used in traditional Far Eastern medicine for hair growth promotion. Junlatat & Sripanidkulchai (2014) examined the effects on hair growth both in vitro and following topical application in vivo in mice of a hydroxysafflor yellow A-rich ethanolic extract prepared from the florets. They observed suppression of a factor associated with hair loss in vitro and also hair growth stimulation in vivo.

An extract of the flowers was strongly phototoxic to three test micro-organisms (Wat et al. 1980b), suggesting the presence of polyacetylenes and/or thiophenes (Towers et al. 1977b). See also Bidens pilosa L. above and Tagetes L. below.

Cassinia aculeata R.Br.
Australian Dogwood

Noyes (1899) described seven cases of eczema from this plant. Irritation occurred in skin folds where pollen or particles of bark accumulated. The disorder has been known in Australia as "mountain itch" (Maiden 1909b). Badham (1931) also refers to contact dermatitis from this species. According to Cleland (1943), the plant causes dermatitis of the exposed skin and also conjunctivitis. Persons employed in clearing the plant from the ground or working in Cassinia scrub developed dermatitis only after being exposed to it for a considerable time (Cleland 1943), suggesting an allergic effect. Bee keepers can develop itching from propolis originating from this plant (Rayment 1935).

Centaurea L.

One species occurs in Australia, and about 600 are found in Europe and northern Africa to northern India and northern China, and in temperate North and South America. The genus is classified in the tribe Cynareae.

The spines on many of the species can cause mechanical injury (Pammel 1911). Some species are probably allergenic since Hjorth (1965) recorded two positive patch test reactions among many tests.

In California, USA, the yellow star thistle (Centaurea solstitialis L.) is responsible in horses for nigropallidal encephalomalacia, otherwise known as "chewing disease" (Herz 1978).

Centaurea americana Nutt.
Sultana Star Thistle, Basket Flower

An extract of the plant produced positive patch test reactions in two of 50 patients in the southern United States who had "weed dermatitis" (Shelmire 1940).

Centaurea calcitrapa L.
Star Thistle

The plant is irritant (Pammel 1911). Potentially allergenic sesquiterpene lactones have been isolated from this species.

Centaurea cyanus L.
Cornflower, Blue-Bottle, Bluet, Batchelor's Button

Frain-Bell & Johnson (1979) observed positive patch test reactions to the oleoresin on this species in 5 from 55 patients with the photosensitivity dermatitis and actinic reticuloid syndrome. Thune & Solberg (1980) observed positive patch test reactions to the oleoresin from this species in a photosensitive and lichen-allergic patient.

Richard J. Schmidt

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