_embryo._ The dormant plantlet comprising part of the seed. It is enclosed within the seed-coats. Its parts are the caulicle (or stemlet), cotyledons or seed-leaves, and plumule. The food may be stored in the embryo, or around the embryo (endosperm). _endogen._ A plant of the monocotyledon class, not enlarging in diameter by means of outside rings; as palms. All grasses and lilies and orchids and cereal grains are of this kind. Now used, if at all, to express a general mode of growth rather than a class of plants. See _exogen_. _endosperm._ The food material that is packed around the embryo (rather than inside it) in the seed. _entomophilous._ Said of flowers that are pollinated by insects. _environment._ The surroundings; or the conditions in which a plant or animal lives. The environment comprises the soil, climate, and the influence of the other plants and animals with which or among which the plant or animal grows. _epicotyl._ The internode or “joint” above the seed-leaves or cotyledons. _epidermis._ The outermost layer or part of the cortex; the skin. _epigeal._ Said of seeds (as common bean) in which the cotyledons or seed-leaves rise above ground in germination. See _hypogeal_. _epiphyte._ A plant that grows on another plant, or on other objects above ground, but which does not derive much or any of its nourishment from its host; an air-plant. _excurrent._ Said of trees (as firs and spruces) in which the main trunk or leader continues through the tree top. _exogen_ (see _endogen_). Of the dicotyledon class, the stem enlarging by external layers or rings. _fertilization_ takes place in the flower when a pollen nucleus and an egg-cell nucleus unite in a forming ovule. _fibro-vascular._ Bundles or strands of tissue composed of sieve-tubes, mechanical fibre and vessels or ducts. _filament._ The stalk part of a stamen. _follicle._ A single-cavity fruit or pod opening along its inner edge. _frond._ A leaf of a fern and related plants. _fruit._ In botany, the ripened ovary with the attached parts. All flowering plants, therefore, produce fruits. The term is also used for the ripened reproductive bodies of flowerless plants. _fruit-dot_, _sorus_. A collection or cluster of sporangia, as in ferns. _function._ What a plant or an organ does; how it works. _gamete._ A cell or nucleus that takes part in fertilization. _gametophyte._ The stage of the plant (as the prothallus) that bears or produces the sex organs; sexual stage of the plant. _gamopetalous._ Said of a corolla with the petals united. _gamosepalous._ Said of a calyx with the sepals united. _generation._ The entire life period of a plant. _geotropism._ Turning toward the earth, as the action of the roots. _glomerule._ A dense globular or oblong flower-cluster in which the upper or inner flowers open first.