Ripe seeds are light brown to brown or olive green. Mimosa is hard seeded. Seeds can survive at least 23 years on sandy soils, but seed viability decreases more rapidly on clay soils. "Mimosa pigra "can germinate year round if the soil is moist but not flooded. However, most germination takes place at the start and end of the wet season. Growth in a seedling is rapid, and flowering occurs between 4 and 12 months after germination. The process from flower bud to ripe seed takes about five weeks. "Mimosa pigra" is closely related to "Mimosa pudica" (common sensitive plant). It can be distinguished from "Mimosa pudica" by its large size, large pods (6 to 8 cm long as opposed to 2.5 cm long) and leaves, which have 6 to 16 pairs of pinnae as opposed to 1 to 2 pairs on "Mimosa pudica" leaves. "Mimosa pigra" is native to tropical America, where it occurs in a wide belt extending from Mexico through Central America to Northern Argentina. It is now widespread throughout the tropics and is a serious weed in Africa, India, South-East Asia (in Cambodia, it is called ព្រះខ្លបយក្ស /prĕəh kʰlɑːp jĕəʔ/ “giant mimosa,” បន្លាយួន /bɑnlaː juən/ “Vietnamese thorn”, or បន្លាយក្ស /bɑnlaː jĕəʔ/ “giant’s thorn”), Australia and some Pacific Islands. "Mimosa pigra" favours wet, tropical climates. It does not appear to grow preferentially in any one soil type, but is most commonly found in moist situations such as floodplains and river banks in soils ranging from black cracking clays throughout sandy clays to coarse siliceous river sand. "Mimosa pigra" is on the list on the world's 100 worst invasive species in the Invasive Species Specialist Groups Global Invasive Species Database.