(Daisy or Sunflower family)
- Flaveria chloraefolia A.Gray
- Flaveria repanda Lagasca
- (syn. Flaveria trinervata Baillon)
The roots of both of these species have been reported to contain the phototoxic thiophene α-terthienyl (Bohlmann et al. 1973, Bohlmann et al. 1978a, Bohlmann & Kleine 1963, Gommers & Voor in't Holt 1976). See also Tagetes L.
- Fleischmannia Sch.Bip.
About 80 species from Central America are now included in this genus, many having been moved from Eupatorium L.
- Fleischmannia pycnocephala R.King & H.Robinson
- (syn. Eupatorium pycnocephalum Less.)
Bohlmann et al. (1977b) report the isolation of sesamin from this species. Sesamin is known for its role in sesame oil (Sesamum indicum L., fam. Pedaliaceae) contact allergy.
- Gaillardia Foug.
- Blanket Flower, Firewheel
Some 26 species are found in North America, a further 2 in temperate South America. The genus is classified in the tribe Helenieae.
The popularly grown perennial border plants known as gaillardias are cultivars mostly derived from G. aristata Pursh. They may also be called Gaillardia x grandiflora hort. or G. gigantea, G. hybrida, G. maxima, etc. — names that are of no botanical standing.
Three cases of contact dermatitis from Gaillardia were reported by Rostenberg & Good (1935); one of the three patients was also contact sensitive to an Ambrosia L. and pyrethrum (Chrysanthemum L. sp.). Patients who were contact sensitive to Gaillardia also showed positive patch test reactions to Helenium L., Parthenium L., and Tanacetum L. species (Mitchell 1972). Tan & Mitchell (1968) observed positive patch test reactions to an unspecified Gaillardia species in photosensitive and lichen allergic patients with so-called "cedar-poisoning" who were also sensitive to various members of the Compositae.
Potentially allergenic sesquiterpene lactones (Mitchell & Dupuis 1971) have been reported from a number of species:
- Gaillardia amblyodon Gay
- Gaillardia arizonica A.Gray
- Gaillardia fastigiata Greene
- Gaillardia x grandiflora hort.
- Gaillardia megapotamica Baker
- Gaillardia mexicana A.Gray
- Gaillardia multiceps Greene
- Gaillardia parryi Greene (unpublished)
- Gaillardia pinnatifida Torr.
- Gaillardia spathulata A.Gray
Other species are considered in the monographs below.
- Gaillardia aristata Pursh
A female, aged 73 years, had dermatitis of 16 years duration affecting the hands and face; blistering of the hands had previously been noted. Patch tests with plants from her neighbour's garden were applied. Strongly positive reactions to the flower, leaf, and stem of G. aristata were observed, with weakly positive reactions to G. pulchella Foug. The neighbour gave the plants to the patient for indoor decoration (Burry 1980b).
Potentially allergenic sesquiterpene lactones have been reported from this species.
- Gaillardia pulchella Foug.
- (syn. Gaillardia picta Sweet)
In an investigation of "weed dermatitis", 7 of 50 patients were found to be contact sensitive to this species (Shelmire 1939a). A flower-binder, who had recurrent contact dermatitis from this plant, reacted positively to a patch test with the pollen (Zschunke 1955).
Burry (1980b) observed weakly positive patch test reactions to this species in a patient who reacted strongly to G. aristata Pursh.
α-Terthienyl, which is phototoxic to human skin (see Tagetes L. below), has been reported from this species (Gommers & Voor in't Holt 1976) as also have a number of potentially allergenic sesquiterpene lactones.
- Galinsoga parviflora Cav.
- Gallant Soldier
This species has become a common weed in Europe (Willis 1973).
In cases of contact dermatitis from the plant, positive patch test reactions were observed from the stem, leaf, and petal. Patch test reactions to an Anthemis L. species were negative (Möslein 1963). Hausen (1979) reported that the plant has high sensitising capacity in guinea pigs.
- Geraea viscida Blake
- (syn. Encelia viscida A.Gray)
The trichome exudate from this species growing in California, USA yielded gerin, a eudesmane methyl ester. Gerin lacks the lactone ring with an exocyclic methylene group that is normally found in contact allergenic sesquiterpenoids from the Compositae, but was nevertheless found to elicit dermatitis in individuals sensitised to sesquiterpene lactones (Rodriguez & Epstein — unpublished observation, cited by Rodriguez et al. 1979).
- Glebionis carinata Tzvelev
- (syns Chrysanthemum carinatum Schousb., Ismelia carinata Sch.Bip., Ismelia versicolor Cass.)
- Annual Chrysanthemum, Painted Daisy, Tricolor Daisy, Bunte Wucherblume
Robert (1951) described a case of seasonal facial eczema in a male who had visited a business at which he came into the close proximity of a bouquet of "yellow marguerites". The flower in question were identified as "Chrysanthemum carnatum" by a botanist. However, these are not normally yellow, but multicoloured. So, it is possible that the plant was mis-identified.
- Gnephosis Cass.
About 15 species are found in temperate regions of Australia. Some Australian Compositae-sensitive patients show positive patch test reactions to some of these plants (Kirk 1977).
- Grindelia Willd.
Sixty species occur in the Americas. The genus is classified in the tribe Astereae.
An unidentified species of Grindelia, which was a constituent of a proprietary remedy, produced positive patch test reactions in four patients who had previously suffered from plant-induced dermatitis (Underwood & Gaul 1948).
Grindelia robusta Nutt. has been used as a folk remedy for poison ivy (Toxicodendron Mill., fam. Anacardiaceae) dermatitis.
- Gundelia tournefortii L.
- (syns Gundelia glabra Mill., Gundelia purpurascens Bornm., Gundelia tenuisecta Freyn & Sint.)
- Akkoub, A'kub, Galgal, Tournefort's Gundelia, Tumble Thistle, Tumbleweed, Gundele de Levant, Gundélie
The leaves, flowering parts, and fruits of this perennial thistle are spiny (Hind 2013). It occurs naturally in the Middle East and Turkey but is also cultivated, mostly as a food plant but also for its semi-dry inflorescences, which are collected before dehiscence for use as filters in the water collecting entry of cisterns, and also as brooms. The young leaf bases are considered a delicacy. They are used in the local cuisine of Israel, Jordan, and the Palestinian Authority, being collected in large amounts from the wild because market prices are very high. Natural populations of the plant in the area are dwindling due to over-utilisation, having become extinct in some areas. The plant was entered into Israel’s list of plants protected by law, and is also partly protected in the Palestinian Authority. However, illegal collecting is very common. In order to meet demand, it has been cultivated since the turn of the century both in Israel and in the Palestinian Authority. The spines present a great challenge in cultivation (Vitek et al. 2017).
The genus Gundelia L. has been considered by some authorities to be monotypic (Vitek et al. 2017), and by other authorities to comprise up to four (Mabberley 2017), twelve, or sixteen species. All are strongly spiny thistles capable of inflicting mechanical injury.
- Gynura pinnatifida DC.
- Mountain Varnish
The plant, which is known as Shan Chi in Chinese traditional medicine, has the property of causing the edges of wounds to adhere together. Vulnerary, styptic, and astringent properties of a very high degree are ascribed to both the rhizome and the leaves (Stuart 1911).