form

noun

(L. forma: shape) A small but constant variation within a population of plants, such as a white-flowered plant in a normally purple-flowered population. A category ranking below a subspecies, used chiefly for certain minor variations (e.g. the yellow passion fruit, Passiflora edulis flavicarpa, whose fruit is yellow rather than purple as in P. edulis proper); a sporadic variant, equivalent to `variety' of some botanists but generally trivial such as corolla or fruit color or habit response.