Tinospora
Description
Woody climbers.
Leaves with petiole swollen and geniculate at base, lamina often ± cordate, margin usually entire, occasionally dentate, rarely 3-lobed, palmatinerved mostly with 3-5 basal nerves and 1-3 pairs of distal lateral nerves, sometimes with domatia or glandular patches present in the basal nerve-axils.
Inflorescences thyrsoid, pseudopaniculate, pseudoracemose or pseudospicate, in some species not coetaneous with the leaves.
Distribution
Asia present, Asia-Tropical, Australasia, Madagascar present, Old World present, Pacific present, Tropical Africa present
An Old World genus of 32 species: 7 in tropical Africa, 2 in Madagascar, 23 in Asia to Australia and the Pacific, throughout Malesia.
Ecology
An important study by Dr. H. BÄNZiGER on fruit-piercing moths in Thailand () has demonstrated the important role played by species of Tinospora in the biological chain which leads to extensive damage to certain fruit crops in Thailand. Longan (Dimocarpus longan LOUR.) and citrus including mandarin are the main crops damaged by noctuid Lepidoptera which feed on the sap by piercing the skin of the fruits. In Thailand the moth mainly responsible is Othreis fullonia. Dr. BÄNZI-GER has demonstrated that the chief host plants for the larval stage are T. sinensis and T. crispa throughout Thailand and T. baenzigeri in Central, S. and NE. Thailand. Other species of Menispermaceae also act as hosts for the larvae, especially in periods when these species of Tinospora are leafless during the dry season, which is more prolonged in the north. These three species of Tinospora in Thailand are typical components of secondary vegetation, where forest has been destroyed or disturbed. The exceptional capacity of these climbers to survive damage and to regenerate from detached lengths of stem encourages their spread in these disturbed habitats. It is therefore apparent that destruction of forests in Thailand leads to the spread of Tinospora, which in turn promotes the increase of noctuid moths, which damage the fruit crops.
Morphology
There are various types of inflorescence in the genus and the flowers also vary appreciably. The flowers are basically arranged in cymes, but these are sometimes reduced to single flowers, which can be sessile. The inflorescences can be apparently paniculate, racemose or spiciform. A thyrse, consisting of a raceme of lax cymes, occurs in T. trilobata. A pseudopaniculate inflorescence occurs in T. dentata and T. dissitiflora, and apparently also in T. arfakiana and T. hirsuta, where only infructescences are known.
The sepals of T. trilobata are unusual in being connate at the base, while in the other species they are completely free. Most species have unequal sepals, the outer whorl of three being smaller, but in T. dentata, T. homosepala, T. sumatrana, T. trilobata and sometimes in T. sagittata they are subequal. In T. tinosporoides, T. trilobata (and occasionally in T. cordifolia and T. merrilliana) there are up to three minute sepals in an additional outer whorl. The petals are generally 6 in number, opposite to the equal number of stamens, but in T. crispa only the outer whorl of three petals usually develops. Although minute in size, the petals do vary in form between species but fortunately we do not have to rely on them in order to distinguish the species.
The sepals of T. trilobata are unusual in being connate at the base, while in the other species they are completely free. Most species have unequal sepals, the outer whorl of three being smaller, but in T. dentata, T. homosepala, T. sumatrana, T. trilobata and sometimes in T. sagittata they are subequal. In T. tinosporoides, T. trilobata (and occasionally in T. cordifolia and T. merrilliana) there are up to three minute sepals in an additional outer whorl. The petals are generally 6 in number, opposite to the equal number of stamens, but in T. crispa only the outer whorl of three petals usually develops. Although minute in size, the petals do vary in form between species but fortunately we do not have to rely on them in order to distinguish the species.
Notes
Tinospora has proved particularly difficult to revise owing to the incompleteness of the material of several species and the fact that some species flower when the plants are leafless.
If complete material were known for all the species, it should not be difficult to provide separate keys for male flowering, female flowering and fruiting plants. Male flowers, female flowers or fruits are unknown for some species, and it is therefore impossible at present to provide a key using only morphological characters which would work for every single specimen, whether flowering or fruiting.
If complete material were known for all the species, it should not be difficult to provide separate keys for male flowering, female flowering and fruiting plants. Male flowers, female flowers or fruits are unknown for some species, and it is therefore impossible at present to provide a key using only morphological characters which would work for every single specimen, whether flowering or fruiting.
Phytochemo
BISSET () discussed the fairly numerous researches on alkaloids and bitter substances found in the species, and provided a bibliography.
Citation
TROUPIN 1962: Monogr. Menisp. afric.: 191
FORMAN 1981 – In: Kew Bull.: 379
MIERS 1871 – In: Contr. Bot.: 30
MIERS 1864 – In: Ann. Mag. Nat. Hist.: 315
HOOK.f. & TH. 1872 – In: Fl. Br. India: 96
Diels 1910: p. 133. – In: Pfl. R.: f. 49
BACK. & BAKH.f 1963 – In: Fl. Java: 157
F.M. BAILEY 1899 – In: Queensl. Fl.: 29
HOOK.f. & TH. 1855: Fl. Ind.: 182
Diels 1910 – In: Pfl. R.: 133
MIERS 1984 – In: Kew Bull.: 112