Rufescent: reddish.
Rufous: brick-red [chronic yellow + dragon's blood].
Ruga, Rugulae: a wrinkle; small wrinkles.
Rugose -ous: wrinkled: with irregular waved elevated lines.
Rugulose -ous; minutely wrinkled.
Runcinate: notched: cut into several transverse acute segments which point backward.
Ruptor ovi: = egg burster; q.v.
Rutilous: a shining bronze red.
Sabulose: sandy or gritty.