Another reason plants in the garden may be clumping rather than scattered is that burrowing animals may be discouraged more in the garden (I wish I could discourage them a lot more out here!). Plants that produce many small offset bulbs are often those that have evolved along with heavy bulb predation by burrowing or digging animals; the tiny bulblets are not found as easily by the predators and can renew the population. Another factor is soil movement: bulbous plants that inhabit moving scree or gravelly situations, or that grow along swift watercourses (e.g., Lilium pardalinum), are likely to reproduce by tiny offsets that are spread as the substrate breaks them up and moves them along. Jane McGary Northwestern Oregon, USA