plant reproductive system, any of the systems, sexual or asexual, by which plants reproduce. In plants, as in animals, the end result of reproduction is the continuation of a given species, and the ability to reproduce is, therefore, rather conservative, or given to only moderate change, during evolution. Changes have occurred, however, and the pattern is demonstrable through a survey of plant groups.
Reproduction in plants is either asexual or sexual. Asexual reproduction in plants involves a variety of widely disparate methods for producing new plants identical in every respect to the parent. Sexual reproduction, on the other hand, depends on a complex series of basic cellular events, involving chromosomes and their genes, that take place within an elaborate sexual apparatus evolved precisely for the development of new plants in some respects different from the two parents that played a role in their production.
In order to describe the modification of reproductive systems, plant groups must be identified. One convenient classification of organisms sets plants apart from other forms such as bacteria, algae, fungi, and protozoans. Under such an arrangement, the plants, as separated, comprise two major groups—the nonvascular bryophytes (mosses, hornworts, and liverworts) and the vascular tracheophytes. The vascular plants include the seedless lycophytes and ferns (both groups are considered lower vascular plants) and the two groups of seed plants, the gymnosperms and angiosperms.
A comparative treatment of the two patterns of reproductive systems will introduce the terms required for an understanding of the survey of those systems as they appear in selected plant groups.