Receptacle (receptaculum). The extremity of the flower-stalk bearing the floral envelopes and the sexual organs; or the enlarged end of a branch upon which the flowers are seated.
Reduplicate (reduplicatus). Doubled along the midrib with the margins turned outwards.
Reflexed (reflexus). Bent back.
Regular (regularis). With all parts of the same kind, especially all perianth leaves, equal in shape and arrangement.
Reniform (reniformis). Kidney-shaped.
Revolute (revolutus). Rolled backwards from the margins.
Rib (costa). A strong, more or less projecting nerve.
Root-stock (rhizoma). The root-like, underground or prostrate lowest part of the stem of certain plants.
Rotate (rotatus). Wheel-shaped, i.e., with a very short tube and a spreading limb.
Rudimentary (rudimentarius). Very imperfectly developed.