He lieth
shakab (shaw-kab')
to lie down (for rest, sexual connection, decease or any other purpose)
under the shady trees
tse'el (tseh'-el)
the lotus tree -- shady tree.
in the covert
cether (say'-ther)
a cover (in a good or a bad, a literal or a figurative sense) -- backbiting, covering, covert, disguise(-th), hiding place, privily, protection, secret(-ly, place).
of the reed
qaneh (kaw-neh')
a reed (as erect); by resemblance a rod (especially for measuring), shaft, tube, stem, the radius (of the arm), beam (of a steelyard)
and fens
bitstsah (bits-tsaw')
a swamp -- fen, mire(-ry place).