If a full range of species is desired, collection trips should begin in late Spring and continue until Fall. Fruits should be collected when they are ripe and before their seeds have been dispersed. Most fruits will easily dislodge from the plant when they are ripe or close to ripe. In general, physical changes occurring in the fruit signal maturity. These include a change in size, shape, weight, color, or firmness.
Similar changes occur in the seeds.
Break open fruits to examine the seeds. Most ripe seeds will have a dark or rich outer color. Many will be shiny. Break open a few seeds. Examine a few seeds for the presence of endosperm.