Aster (family Compositae)
A genus of mostly perennial herbs
in which the leaves are simple
and spirally arranged, the flower heads have imbricate bracts
and flat, naked receptacles
; ray florets
, usually present, are white, blue, or red, but never yellow but the disc
florets are yellow. The achenes
are flattened and smooth with a pappus
of short, bristly hairs. Many N. American species are cultivated as Michaelmas daisies and have become naturalized in Europe
and elsewhere. There are about 250 species, mostly northern temperate.
as·ter / ˈastər/ •
n. 1. a plant (genus Aster) of the daisy family that has bright rayed flowers, typically purple or pink. Many species, including the New England aster (A. novae-angliae), bloom in autumn.2. Biol. a star-shaped structure formed during division of the nucleus of an animal cell.
A starlike arrangement of microtubules radiating from a centrosome
. Asters become conspicuous in animal cells at the ends of the spindle when cell division
starts. They are believed to help locate the spindle in relation to the cell's boundaries and to trigger cleavage of the cytoplasm when nuclear division is completed.
A group of microtubules
that radiates out from each centriole
pair during cell division
in animal cells.
genus of plants with radiated flowers. XVIII. — modL. use of L. astēr
— Gr. astḗr STAR
Genus of mostly perennial, leafy stemmed plants native to the Americas and Eurasia. Asters are popular garden plants and most bear daisy-like flowers. Family Asteraceae/Compositae.