Two-leaf nightshade (Solanum diphyllum L.)-An addition to the flora of Delhi, India and weed risk assessment of the species

Solanum diphyllum L. (the two-leaf nightshade) is reported as a new record for flora of Delhi. Study of natural populations of the species and weed risk assessment supported it's tendency of widespread naturalization. Plant characters such as high fruit-bearing and high seed number per fruit, perennating root stock, high germination rate, seed dormancy, no natural predators (animal toxicity) and dispersal through movement of soil were the main parameters favouring fast spread of the species. A detailed description of the species along with distribution, propagation and dispersal has been discussed.