saprophyte

sap·ro·phyte /ˈsæprəˌfaɪt/

–noun
any organism that lives on dead organic matter, as certain fungi and bacteria.

Also called saprobe.

Origin:
1870–75; sapro- + -phyte

—Related forms
sap·ro·phyt·ic  /ˌsæprəˈfɪtɪk/ Show Spelled, adjective
sap·ro·phyt·i·cal·ly, adverb

Source: Dictionary.com.

Sellars dropped back into his system and called up his metaphorical Garden … A strange blight had overtaken the Garden. Whole plants were gone, entire sections of stored information corrupted or interdicted. Other information sources had taken on strange new shapes. The saprophytic growth that represented the mysterious operating system had mutated out of all recognition …

Source: Mountain of Black Glass by Tad Williams.

pulverulent

pul·ver·u·lent /pʌlˈvɛryələnt, -ˈvɛrələnt/

–adjective
1. consisting of dust or fine powder.
2. crumbling to dust or powder.
3. covered with dust or powder.

Origin:
1650–60; < L pulverulentus dusty, equiv. to pulver– (s. of pulvis) dust + –ulentus -ulent

—Related forms
pul·ver·u·lence, noun
pul·ver·u·lent·ly, adverb

Source: Dictionary.com.

[A]n attic promises a rather threadbare paradise, where the dead bodies appear in a pulverulent glow, a vegetal elixir that, in the absence of green, makes you feel  you are in a parched tropical forest, an artificial canebreak where you are immersed in a tepid sauna.

Source: The Mysterious Flame of Queen Loana by Umberto Eco.