For a scenic browse, and an answer-page for Guess The World...
...Kah made a sign of warning a little later, and they halted.
"We are near the evil ones' citadel," he whispered. "But the screaming trees will instantly give warning unless we are careful."
Captain Future saw ahead of them an extensive forest of the strange trees, their big leaves hanging limp.
"Walk as softly and slowly as you can," Kah was warning. "Any sudden movement will set the trees in uproar."
He led the way into the weird forest, moving on tiptoe...
Future thought he understood now, that the weird trees were so highly
sensitive to vibrations of the ground that such vibrations set off their
Edmond Hamilton, Outlaw World (1945)
...she told me about the weird, dog-like creatures. The male, exuding a scent - if you could call it that - a vapor which in the air bursts into spontaneous combustion as it combines with the atmospheric oxygen.
long we ran through what proved to be a maze of passages in the
honey-combed ground, I have no idea. Several Earth miles, doubtless.
Several times we stopped to rest, with the breezes tossing about us as I
listened, tense, to be sure the Orgs were not coming. Then at last we
emerged; and at the rocky exit I stood staring, amazed.
where we stood the ground sloped down so that we were looking out over
the top of a wide spread of lush, tangled forest. Weird jungle, rank
and wild with spindly trees of of fantastic shapes, heavy with pods and
exotic flowers and tangled with masses of vines. Beyond it, far ahead
of us there seemed a line of little metal mountains at the horizon; and
to the left an Earth-mile or so away, the forest was broken to disclose a
winding thread of little river. It shone phosphorescent green in the
half light. The storm was over now, but still the colors lingered in
the cloud sky - a glorious palette of rainbow hues up there that tinted
Ray Cummings, The Flame Breathers (Planet Stories, March 1943)