=Acheloüs=, _n._ A river god with whom Hercules wrestled. Like
Proteus, Acheloüs could change his shape; he became a serpent and a
bull, but Hercules vanquished him nevertheless and tore off his
horn, which became the horn of plenty.
=Alternate=, _a._ L. _alter_, another; one following another. Said of
leaves standing singly at the nodes of a stem; also of stamens that
stand between the petals, and of petals that are placed between the
sepals.
=Amalthea=, _n._ In Greek mythology, the nurse of Jupiter, probably a
goat.
=Amœba=, _n._ From a Greek word meaning “change”; the name of one of
the lowest forms of life; a bit of living protoplasm capable of
existing as a single cell and of changing its form at will.
=Ancestors=, _n._ L. _antecessor_, a foregoer; forefathers; those from
whom animals or plants are descended.
=Animal cells=, _n._ The cells or minute divisions which make up the
animal body.
=Animals=, _n._ All living things which are not plants are animals. In
the lower forms of life it is impossible to decide whether certain
living things are animals or plants.
=Anther=, _n._ From a Greek word meaning “flower”; that part of the
stamen containing the pollen.
=Anther cells=, _n._ The hollow spaces in the anther where the pollen
is kept.
=Aristocrat=, _n._ From two Greek words meaning “best” and “rule”; one
belonging to the best in a community; one among those fit to rule.
=Aristocratic=, _a._ Like an aristocrat.
=Axil=, _n._ L. _axilla_, little armpit; the angle formed between the
upper side of a leaf and the stem or branch to which it is attached.
=Azalea=, _n._ The name of a plant. The “swamp honeysuckle” is not a
honeysuckle, but is an azalea.