Reticulated, the veins forming network, [50]. Retiform, in network.

Retinerved, reticulate-veined.

Retroflexed, bent backwards; same as reflexed.

Retuse, blunted; the apex not only obtuse but somewhat indented, [54].

Revolute, rolled backwards, as the margins of many leaves, [72].

Rhachis (the backbone), the axis of a spike or other body, [73].

Rhaphe, the continuation of the seed-stalk along the side of an anatropous ovule or seed, [112], [126].

Rhaphides, crystals, especially needle-shaped ones, in the tissues of plants, [137].

Rhizanthous, flowering from the root.

Rhizoma, Rhizome, a rootstock, [42]-[44].