1. (n.) An edible fungus (Agaricus campestris), having a white stalk which bears a convex or oven flattish expanded portion called the pileus. This is whitish and silky or somewhat scaly above, and bears on the under side radiating gills which are at first flesh-colored, but gradually become brown. The plant grows in rich pastures and is proverbial for rapidity of growth and shortness of duration. It has a pleasant smell, and is largely used as food. It is also cultivated from spawn.

2. (n.) Any large fungus, especially one of the genus Agaricus; a toadstool. Several species are edible; but many are very poisonous.

3. (n.) One who rises suddenly from a low condition in life; an upstart.

4. (a.) of or pertaining to mushrooms.

5. (a.) Resembling mushrooms in rapidity of growth and shortness of duration; short-lived; ephemeral; as, mushroom cities.

Ectocarpales Phaeophyceae algae autophyte ball balloon bead bean blossom blow up bracken brew brown algae burgeon burst climber conferva confervoid conglobulate creeper detonate develop diatom fern flourish fruits and vegetables fucus fungi fungus gather germinate globe go off grapevine green algae grow grow up gulfweed herb heterophyte hypertrophy increase ivy kelp legume lentil liana lichen liverwort mature mold molds moss newly-rich nouveau-riche outgrow overdevelop overgrow overtop parasite parasitic plant parvenu pea perthophyte phytoplankton planktonic algae plant families procreate puffball pullulate pulse red algae reproduce rockweed rust saprophyte sargasso sargassum sea lentil sea moss sea wrack seaweed shoot up smut snowball sphere spherify spring up sprout sprout up succulent thallogens thrive toadstool tower upshoot upspear upspring upsprout upstart vegetate vetch vine wax wort wrack