Lecture 18: Angiosperm Floral Diversity Flashcards
A complete flower
has all 4 floral series present (calyx, corolla, ardroecium, gynoecium)
An incomplete flower
lacks one or more floral series
A perfect flower
has a functional androecium and gynoecium (bisexual)
An imperfect flower
lacks a functional androecium or a functional gynoecium (unisexual)
A sterile flower
lacks a functional androecium and a fucntional gynoecium. (usually found in clusters where some flowers are sterile and some not)
A staminate flower
has a functional androecium but not a functional gynoecium
A pistillate flower
has a functional gynoecium but not a functional androecium
Actinomorphic
Radially symmetrical
‘regular’ flowers show no variation in size, shape, and orientation of parts within each floral series.
(standard orientation is looking down axis of strobilis)
Zygomorphic
bilaterally symmetrical, or ‘irregular’
divisible into mirror images along only one plane, also applied to asymmetrical flowers
(standard orientation is looking down axis of strobilis)
why are angiosperms so diverse?
1) the 4 floral series have become modified during evolution
2) changes in the number of each floral part per flower, attachment of parts to the receptacle, and how these parts are fused
stamens
microsporophylls, but do not resemble leaves.
comprised of a filament and an anther
carpels
megasporophylls that are folded and fused along margins
some primitive carpels are not fused
and instead have glandular trichomes, and a stigmatic crest along which pollen germinates
hypogyny
floral parts below gynoecium
ovary superior
perigyny
floral parts attached to the rim of a hypanthium that surrounds some or most of the gynoecium
ovary superior
epigyny
hypanthium fused to ovary, with floral parts attached above it
ovary inferior
dioecious
a species with imperfect flowers is diocious if staminate flowers are borne on one sporophyte and pistillate flowers are born on a different sporophyte
monoecious
a species with imperfect flowers is monoecious if staminate and pistillate flowers are borne on one and the same sporophyte
Inflorescence
a cluster of flowers