Clitoria ternatea (butterfly-pea).
Abstract Genetics: The chromosome number reported for C. ternatea varies from 2n = 14 to 2n = 16 (Gandhi and Patil, 1993; Flora of China Editorial Committee, 2016). Breeding system: Flowers of C. ternatea are cleistogamous, but a small level of outcrossing occurs and most flowers are self-pollinated. In the wild, flowers are visited by insects, primarily bees (Staples, 1992). Physiology and Phenology: C. ternatea is a perennial climbing, scrambling or trailing herb with a strong woody rootstock. Individual plants may live for several years and grow into large vines if undisturbed. C. ternatea shows epigeal germination. The radicle emerges within 48-72 hours and seedlings emerge in 3-6 days. Early growth is rapid in warm moist conditions. This fast-growing herb can cover the ground in 4-6 weeks when sown at a population of 4 plants/m2 (Staples, 1992; Cook et al., 2005). Growth of established plants is mostly from the apices of the main axis and axillary branches; very few new shoots arise from ground level. Growth is more or less continuous in the tropics (Staples, 1992; Cook et al., 2005).In China, C. ternatea has been recorded flowering and fruiting from June to November (Flora of China Editorial Committee, 2016). In Panama, it has been collected with flowers in February, April, July, August and November (Flora of Panama, 2016). In Costa Rica, flowering can occur throughout the year (Missouri Botanical Garden, 2016). Pods mature in 8-10 weeks after flowering and break readily once fully dry. Hand-harvested seed often remains hard-seeded for a long time and requires scarification prior to sowing. Mechanical abrasion, hot water or sulphuric acid can be used to break this dormancy (Staples, 1992; Cook et al., 2005; FAO, 2016). Associations: As with other nitrogen-fixing legumes, C. ternatea has a symbiotic relationship with Rhizobium bacteria (Cook et al., 2005). In cultivation, C. ternatea has been grown successfully with Pennisetum purpureum, Digitaria eriantha, Andropogon gayanus, Dichanthium aristatum, Cenchrus ciliaris, Chloris gayana, Sorghum bicolor, and Megathyrsus maximum (Cook et al., 2005). Environmental Requirements: C. ternatea prefers to grow in humid and sub-humid habitats at elevations from sea level to 1600-1800 m and mean annual temperature ranging from 15 to 28°C (Staples, 1992). It is adapted to a wide range of soil types from sandy to deep alluvial loams and heavy clays with pH ranging from 5.5 to 8.9 (McCosker and Osten, 1999; FAO, 2016). This species shows drought tolerance and it is able to grow in dry and semiarid habitats with annual rainfall ranging from 500 to 900 mm and survive for up to 5-6 months with only 400 mm of rainfall. C. ternatea also shows moderate frost tolerance and some tolerance to salinity conditions. This species does not tolerate flooding or waterlogging. It is normally grown in full sunlight but moderately shade-tolerant (Staples, 1992; Cook et al., 2005; FAO, 2016).
Flora of China, vols. 2–3, Lycopodiaceae through Polypodiaceae Flora of China, vols. 2–3, Lycopodiaceae through Polypodiaceae. Wu Zhengyi and Peter H Raven, Co-chairs of the Editorial Committee and Hong Deyuan, Vice Co-chair of the Editorial Committee . Science Press (Beijing) and Missouri Botanical Garden Press (St. Louis). ISBN 978-0-915279-34-0 (series), ISBN 978-1-935641-11-7 (vols. 2—3). Publication date: 6 June 2013.
