Changes

:Chromosome number: ''x''= 20, 40;''C. japonica'': 2''n''= 40, 60,''C. mollissima'': 2''n''= 40,''C. trifolia'': 2n = 40, 80, about 96

In South-East Asia, different plant parts of ''Cayratia'' are commonly applied for fever. In Peninsular Malaysia, the leaves of ''C. japonica'' , boiled with an onion and lime, are applied to the head to cure violent headaches. The dried and powdered flowers are employed for fever. In Sumatra, all aerial parts are applied for fevers, including malaria. In the Solomon Islands, the leaves are rubbed on the stomach to relieve constipation. In China, the aerial parts or the roots are widely used for fever, and also to resolve toxins in mumps, jaundice and dysentery and disperse swellings in rheumatism. The mucilaginous roots are also employed to treat cancerous affections, and also act as a diuretic to treat haematuria. In decoction, the roots are applied for mastitis. Pounded leaves are put on scorpion stings and centipede bites.

In Peninsular Malaysia and East New Britain, the leaves of ''C. trifolia'' are commonly used for poulticing ulcers of the nose. The leaves or roots also act as a rubefacient, drawing blood to the surface. The leaves or roots in decoction are used as a fomentation for high fever, resulting in perspiration. The juice from the leaves and stems may also be drunk, diluted in water, for the same purpose. In Java, the juice of the leaves, together with the juice of young pineapple, may be used on the head for itch and dandruff. In Thailand, the leaves and roots are used for fever and as an astringent, the stem as an expectorant, carminative and blood purifier. The stem is applied to relieve vertigo, fainting, internal bruises, boils and nose ulcers. In the Philippines and Thailand, a decoction of the leaves or the juice of the fresh leaves is considered antiscorbutic. In India, the ground root, together with black pepper ( ''Piper nigrum'' L.), is applied to boils, as an astringent and disinfectant. In Vietnam, the sap from the cut stem is drunk, but no use is given.

The stem, leaves and root of ''C. trifolia'' contain cyanic acid, and traces of it were also found in the flowers. The leaves of ''C. trifolia'' , ''C. mollissima'' and ''C. japonica'' contain several flavonoids including cyanidin, delphinidin, kaempferol, myricetin and quercetin. Furthermore, the aerial parts of ''C. trifolia'' contain the triterpene epifriedelanol. This compound demonstrated anti-tumour activity in a potato disk bioassay against crown gall tumours caused by ''Agrobacterium tumefaciens'' .

*Perennial, evergreen or deciduous, climbing or scrambling lianas, climbing by leaf-opposed tendrils, often branched several times, branches subtended by a bract; roots sometimes tuberous. *Leaves alternate, pinnate or pedate, 3-12-foliolate, margins serrate; petiole present; stipules 2, often triangular, caducous. *Inflorescence axillary, pseudo-axillary or leaf-opposed, pedunculate, carried above the leaves, multi-flowered in irregular corymbose cymes, often loose; peduncle and pedicel subtended by bracts. *Flowers bisexual, small, 4-merous, buds often swollen; calyx usually cup-shaped; corolla with 4 lobes, free, cohering in bud by the interlocked epidermis cells; stamens 4, inserted on the receptacle at the base of the disk, opposite the petals, filaments erect, often flattened, anthers dorsifixed, opening by longitudinal slits, introrse; disk cupular, adnate to and entirely surrounded by ovary, lobes 4, rounded; ovary superior, 2-locular, 2 ovules per locule; style conical, stigma minute, accrescent. *Fruit a fleshy berry, 1-4-seeded, on the ventral side with 2 grooves. *Seed triangular to ovoid, shape depending on number of seeds in berry, flattened, with 1-2 furrows or pits on the ventral surface; endosperm in transverse section U- or T-shaped. *Seedling with epigeal germination.

In Japan, nectar secretion in ''C. japonica'' lasts for 2 days, and nectar volume peaks at 11 a.m. and 3 p.m. each day, with a sugar concentration of 60%. The commonest visitors were the ant ''Lasius niger'' and the wasp ''Vespa xanthoptera'' .

In ''Cayratia'' , leaf-size, margin indentation and degree of pubescence varies considerably intraspecifically, but number of leaflets, shape and relative size, position of hairs, nature of tendrils and seed characteristics are useful diagnostic characters.

''Cayratia'' is a host of the grape Cristulariella leaf spot ( ''Cristulariella moricola'' ), which causes severe damage on the grape ( ''Vitis vinifera'' L.), and ''C. japonica'' is a host of ''Pseudomonas cissicola'' , the causal agent of bacterial leaf spot on grape and related genera. ''Cayratia'' is resistant to the fungus causing grape downy mildew ( ''Plasmopara viticola'' ).

''Cayratia'' is also an alternative host for the cotton aphid ( ''Aphis gossypii'' ). ''C. japonica'' is an alternative host for the Lepidopteran ''Scrobigera amatrix'' , which feeds on the leaves of grapes.

The ''Cayratia'' species treated here are widespread and common throughout South-East Asia, and do not seem to be at risk of genetic erosion. There are no known breeding programmes of ''Cayratia'' .

Little information is available on the phytochemistry and phytopharmacology of ''Cayratia'' . More research will be needed for a proper evaluation of its future potential, e.g. as a febrifuge.