The word psilophytes is playable in Words With Friends™, no blanks required. Because it is longer than 7 letters, you would have to play off an existing word or do it in several moves.
Words With Friends™ Letter Score: 22
Highest Scoring Words With Friends™ Play In The Letters psilophytes
:
Seven Letter Word Alert: (29 words)
hippest, holiest, hoplite, hopples, hostels, hostile, isohels, isohyet, isotype, pisspot, pistols, pitless, postils, potpies, soppily, spyhole, stipple, stipply, stylise, stylish, stylops, systole, tipless, tipples, topless, topples, toyless, tyloses, tylosis