hysterophyte

from The Century Dictionary.

• noun Properly, a member of the Hysterophyta; a fungus of any kind; in common usage, any fungus growing upon organic matter, from which it derives its nourishment; a saprophyte.
• noun In phytogeography, a herbaceous plant which does not elaborate its own nourishment, that is, a saprophyte or parasite: opposed to autophyte.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Bot.) A plant, like the fungus, which lives on dead or living organic matter.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun botany A plant or fungus that lives on dead or living organic matter.