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puberty

(Encyclopedia)puberty pyo͞oˈbərtē [key], period during which the onset of sexual maturity occurs. It usually takes place between the ages of 10 and 15 in both sexes but sometimes occurs as early as 7 or 8 years...

pine nut

(Encyclopedia)pine nut or piñon pĭnˈyən, pēˈnyōn [key], edible seed of various species of pine trees. Among the North American species that bear such edible seeds are the nut pines or piñons, Pinus edulis a...

Chlorophyta

(Encyclopedia)Chlorophyta klōrŏfˈətə [key], phylum (division) of the kingdom Protista consisting of the photosynthetic organisms commonly known as green algae. The organisms are largely aquatic or marine. The ...

protozoan

(Encyclopedia)protozoan prōˌtəzōˈən [key], informal term for the unicellular heterotrophs of the kingdom Protista. Protozoans comprise a large, diverse assortment of microscopic or near-microscopic organisms ...

gametophyte

(Encyclopedia)gametophyte gəmēˈtəfītˌ [key], phase of plant life cycles in which the gametes, i.e., egg and sperm, are produced. The gametophyte is haploid, that is, each cell contains a single complete set o...

tsetse fly

(Encyclopedia)tsetse fly tsĕtˈsē [key], name for any of several bloodsucking African flies of the genus Glossina, and in the same family as the housefly. The larva of the tsetse fly develops inside the body of t...

propagation of plants

(Encyclopedia)propagation of plants is effected in nature chiefly sexually by the seed and the spore, less often by rhizomes and other methods (see reproduction). Vegetative means include cutting, layering, graftin...

horsetail

(Encyclopedia)horsetail, any plant of the genus Equisetum [Lat.,=horse bristle], the single surviving genus of a large group (Equisetophyta) of primitive vascular plants. Like the ferns and club mosses, relatives o...

Asian carp

(Encyclopedia)Asian carp, term for several large, hardy freshwater fish of the family Cyprinidae (the minnow family) that are native to E Asia and have become invasive species in the United States. The fish, which ...

spore

(Encyclopedia)spore, term applied both to a resistant or resting stage occurring among various unicellular organisms (especially bacteria) and to an asexual reproductive cell produced by many unicellular plants and...