Menispermaceae (botanical Latin: 'moonseed family' from Greek mene 'crescent moon' and sperma 'seed') is a family of flowering plants. The alkaloid tubocurarine, a neuromuscular blocker and the active ingredient in the 'tube curare' form of the dart poison curare, is derived from the South American liana Chondrodendron tomentosum, which belongs to this family. Several other South American genera belonging to the family have been used to prepare the 'pot' and 'calabash' forms of curare. The family contains 81 genera with some 440 species, which are distributed throughout low-lying tropical areas with some species present in temperate and arid regions.
Description
Menispermaceae are rapidly growing, twining, ever-growing, and woody climbing plants. Rarely, they are upright shrubs, small trees, herbaceous plants or epiphytes (Stephania cyanantha). They can be perennial or deciduous, and have simple to uni-serrate hairs. They usually wind anti-clockwise, although Stephania winds clockwise. The leaves are alternating, or arranged in a spiral. The leaves can be simple, dentate, entire, or lobed. In Syntriandrium, the leaves are bi- or trifoliate. Leaves are frequently peltate, have stems, and lack stipules. The stipules sometimes form spines, as in Antizoma. The leaves are usually bifacial, though they are isofacial in Antizoma. The leaf venation can be almost parallel, or curved. Arcangelisia and Anamirta have hydathodes derived from trichomes. Domatia are present in five genera as pits or hair tufts. Menispermaceae have various types of stomata, which are frequently cyclocytic. Phylloclades are present in Cocculus balfourii. The plants are usually unisexual and dioecious. Tiliacora acuminata and Parabaena tend to have bisexual flowers. Inflorescences are sometimes racemiform, may be derived from a thyrse with partial inflorescences, and are sometimes paniculate. The inflorescences have multiple flowers, or rarely single or paired flowers. Flowers may be axillary, or cauliflorous. The female specimens are often less branched. The flowers are small, and regular or slightly irregular (Antizoma, Cyclea, Cissampelos have irregular flowers). They may be cyclic to irregularly spiral. The receptacle has a developed gynophore. Sepals and petals are in whorls of three or six. There are three to twelve (or more) sepals, which are free or slightly fused, and are imbricate or valvate. Petals are similar, though they may be less numerous (often zero to six). The stamens are free of the perianth, free or fused together in 2–5, fasciculate or monadelphous, and introrse. The dehiscence is along longitudinal, oblique or transversal slits. The female flowers are sometimes with staminodes. The fruitlets are always apocarpous. They may be superior, have three to six carpels, and are usually oppositipetalous. The stigma are apical, dry, and papillous. There are two ovules per carpel, which are anatropous to campilotropous, uni- or bitegmic. The superior is epitropous and fertile, and the inferior apotropous and abortive, and placentation is marginal ventral. Male flowers sometimes have carpelodes. The fruits (usually stipitate drupes) are compound. Each unit is straight or flattened, and asymmetric. The exocarp is usually leathery, and the mesocarp may be thin and fibrous fleshy, or juicy. The endocarp is woody to petrous, rough, tuberous, echinate or ribbed, and often has an outgrowth in the placenta called a condyle. The seeds are spiral (in Limaciopsis and Spirospermum). The seeds may or may not have an endosperm. They are totally or only ventrally ruminate or not ruminate, and oleaginous. The embryo is straight or curved, with flat or cylindrical cotyledons. The cotyledons are leafy or fleshy, and often divaricate. The pollen is tricolpate, with no operculum or ribs. The tectum is perreticulate. A columellate layer and granular endexine is present. The pollen can be colporate, as in Abuta, or syncolporate, as in Tinospora. The chromosome number varies. Many, including Penianthus, Sphenocentrum, Tiliacora, Tinospora, and Stephania have thirteen pairs. Stephania japonica has eleven pairs. Cissampelos pareira has twenty-two pairs. Rhigiocarya racemifera has twelve pairs. Penianthus camerounensis, Menispermum, Sinomenium, and Cocculus are tetraploid, with fifty-two pairs of chromosomes. Cocculus carolinus and Cocculus orbiculatus are hexaploid.
Ecology It is thought that the cauliflorous species are pollinated by small bees, beetles or flies although there are no direct observations of this. Birds disperse the purple or black drupes, for example Sayornis phoebe (a tyrant flycatcher) eats the fruit of Cocculus. In Tinospora cordifolia a lapse of 6–8 weeks has been observed between fertilization and the first zygotic cell division. The Menispermaceae predominantly inhabit low elevation tropical forests (up to 2,100m), where they are climbers, but some genera and species have adapted to arid locations (Antizoma species have adapted to the South African deserts or Cebatha balfourii and its phylloclades have adapted to the climate on the island of Socotra) and other temperate climates. C3 photosynthesis has been recorded in Menispermum.
Phytochemistry The family contains a wide range of benzylisoquinoline compounds (alkaloids) and lignans such as furofuran, flavones and flavonols and some proanthocyanidins.The most notable are the wide variety of alkaloids derived from benzyltetrahydroisoquinoline and aporphine, which accumulate as dimers, as well as the alkaloids derived from morphinan and from hasubanan and other diverse types of alkaloid such as derivative of aza-fluoranthene. Sesquiterpenes such as picrotoxin and diterpenes are also present, while the triterpenes are scarce, and where present are similar to oleanane. Ecdysone steroids have also been found. Some species are cyanogenic.
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