Raceme - An elongated flower cluster in which flowers grow on pedicels along part of the length of the peduncle.
Radical - Growing from or pertaining to a root; growing from a non-aerial stem.
Ray Flower - One of the flattened, petal-like outer flowers or florets ringing the disk in the heads of some composite flowers, such as the daisy. (see also disk flower).
Receptacle - The end of the stem or stalk on which the flower parts are borne.
Rhizome - An underground portion of a stem, producing shoots on top and roots beneath; different from a root in that it has buds, nodes, and scaly leaves; rootstock.
Rootstock - Rhizome.
Rosette - A circular or spiral arrangement of leaves growing from a centre or crown.
Runner - A thin stem or shoot growing along the ground and producing roots at the nodes.