neck

noun

In plants, any constricted part of a plant, as the narrowed section of a perianth, or the point where the blade joins the sheath in some grass leaves; the sterile basal portion of a capsule, sometimes considerably differentiated; e.g. Trematodon, Bryum, Splachnum; the upper narrow part of an archegonium. Cf. hypophysis, apophysis.