An Amazon review of Doomtime by Mithridates VI of Pontus:

Welcome to the fevered fungal/vegetable nightmares and uncanny vistas of Doris Piserchia. A virtually forgotten science fiction author -- her books are all long out of print -- who deserves to be read and remembered.

Doomtime (1981) is by no means a classic (and not her best work) but should be read for its sheer imaginative and haunting power. Despite the fact that the pacing is poor, the characters undeveloped, and Piserchia's prose often falters, the world she creates is memorable and disturbing (sadly, the volume is "graced" with some atrocious cover art, well, besides that weird bug thing -- a Piserchia staple).

The book opens with Creed surviving an assassination attempt but with the assassin (now missing a section of his brain) attached to Creed's head. How did this happen? Well, Creed's people produce most of their food from a gigantic brass bowl (a technology developed in the distant past) filled with proto-flesh (which gurgles out into various molds creating chickens, etc). The assassin attempted to push Creed into the pool (which Creed cleans for a living) but bubbles of the proto-flesh melded the two together. Perhaps this gives you an idea of Piserchia's imagination?

Creed eventually discovers a series of bizarre occurrences, strange molds near the brass bowl produce pinkish creatures which spin like tornadoes and kill people, people disappear into trees only to reappear, and others hunt him with bows and arrows. He realizes that one can meld with the trees which are suddenly growing prolifically near the city. The green ones are called Tedron and the reddish ones Krake. These trees -- linked to each other by roots and eventually to gigantic Everest sized trees of each color -- are fighting a war between each other. By dipping (melding) into a tree, humans becomes addicted and subtle commands implanted into their minds -- the humans become pawns in their war.

Creed sets off to rectify the situation and meets fungus creatures which meld with humans, strange fungus pools that unravel people's psyches, humans sucked dry by Tedron and Krake, humans mutated beyond recognition by the trees, humans turning into trees, fuzzy smallish fungus which grow around peoples' necks, addicted humans stuck in hibernating trees desperate to meld.... Eventually Creed comes upon the central Tedron and Krake -- separated from each other by a mountain range -- and an unusual secret in their upper limbs.

The most disturbing element of this novel is how little the humans have control over their situation. Entire groups of humans are transformed by these trees -- humans are in no way the superior lifeforms. Piserchia is the master at showing instead of telling -- often in an offhand matter of fact way which intensifies the dread and unease. This has to be one of the more unusual and disturbing worlds I've ever read about.

Sadly, Doomtime's structure is a letdown. The entire middle section drags as characters endlessly explore in groups, get separated, manipulated by the trees, betray their companions, feel sorry for them, escape, get separated, get tree manipulated some more, and go out and explore as if nothing happened. Piserchia clearly did not know how to finish the novel (or perhaps reach her page limit). Also, Piserchia writes using clustered vignettes. Thus, an individual narrative thread rarely goes beyond a page or two. This style is really frustrating.

That said, the world itself with its bizarre technology, creepy female fungus creatures, twirling pink creatures, proto-flesh weapons, tree dipping, fungus melding activities, human transforming, and of course the weather creating world destroying trees, is staggeringly inventive.