Sessility (botany) subsessile, which is not completely sessile. Sessility (botany) In botany, sessility (meaning "sitting", used in the sense of "resting on the surface") is a characteristic of plant parts that have no stalk. Flowers or leaves are borne directly from the stem or peduncle, and thus lack a petiole or pedicel. The leaves of most monocotyledons lack petioles. The term sessility is also used in mycology to describe a fungal fruit body that is attached to or seated directly on the surface of the substrate, lacking a supporting stipe or pedicel. Other examples of sessile flowers include Achyranthus, Saffron, etc. Plant
Plant life-form or tree. Conversely, unrelated species may share a life-form through convergent evolution. While taxonomic classification is concerned with the production of natural classifications (being natural understood either in philosophical basis for pre-evolutionary thinking, or phylogenetically as non-polyphyletic), plant-life form classifications uses other criteria than naturalness, like morphology, physiology and ecology. "Life-form" and "growth-form" are essentially synonymous concepts, despite attempts to restrict the meaning of growth-form to types differing in shoot architecture. Most life form schemes are concerned with vascular plants only. "Plant construction types" may be used in a broader sense to encompass "planktophytes", "benthophytes" (mainly algae) and terrestrial plants.