Flowers

Differentiated Perianths have _______

Sepals (calyx) - outer whorl - often are green - may be smaller than petals - protect the inner parts while in bud Petals (corolla) - inner whorl - often colored and attractive Modifications (sterile stamens)

Flower anatomy

Sepals, Petals Stamen - Male Portion includes Anther and Filament (stalk) Pistil/Carpel - Female Portion includes Stigma, Style (stalk), Ovary, Ovule

Undifferentiated Perianths have ______

Tepals (sepals that look like petals) - no differentiation between petals and sepals -> sepals and petals are indistinguishable by size, shape, or color.

Fertile whorls

androecium and gynoecium (stamens and carpels)

Insertion

attachment of floral parts to receptacle (floral axis) hypogynous, perigynous, epigynous

Sterile whorls

calyx and corolla (sepals and petals) - perianth

carpel vs. pistil

carpel: describes a single unit of stigma-style-ovary - fusion is noted separately pistil: does not distinquish between multiple, fused units vs a single unit - not as informative - if simple, single unit -> carpel - if multiple fused, units -> compound pistil

Stigma

collects pollen - *germination of pollen grains* occur here

Perianth

composed of the calyx (sepals) and corolla (petals) of a flower - outer protective and/or attractive structures - *non-reproductive* part of the flower; *encloses the reproductive part* of the flower - can be differentiated or undifferentiated

Types of fusion

connate, distinct, adnate, free

Style

connects the stigma to the ovary - pollen tubes grow through stylar tissue

Ovules

develops within the ovary, *contains the female gametophyte* (megagametophyte - embryo sac). - contains megagametophyte (embryo sac of angiosperm - female gametophyte) - connected to ovary wall by funiculus - ovary contains the ovules, which contain megagametophytes, the female gametophyte. - ovules develop into seeds, ovaries develop into fruits

Ovary

encloses and protects the ovules and seeds as they develop. - surrounds and protects ovules

Perfect flowers

flowers with both androecium and gynoecium (male and female parts)

Connate fusion

fusion of like-parts - petals fused to petals; carpels fused to carpels

Adnate fusion

fusion of unlike-parts - petals fused to sepals; stamen fused to petals

Nectaries

glands that *produce nectar* - glands often found near the base of the androecium and gynoecium - projections, lobes, disk-like - nectar spurs formed by floral parts (petals)

Complete flowers

have all four floral parts - sepals, petals, stamens, carpels - are always perfect, possess both an androecium and gynoecium -> bisexual

Carpellate flowers

have carpels but not stamens - are *female*

Staminate flowers

have stamens but no carpels (no pistil) - are *male*

Microsporangia

pollen sacs - angiosperm stamens have anthers with four microsporangia

Filament

presents the anther - part of stamen

Plant symmetry

radial symmetry, bilateral symmetry, asymmetrical flowers

4 whorls of a flower

sepals (calyx) petals (corolla) stamen (androecium) carpel (gynoecium) flowers can have all of these or some of them

Epigynous

the ovary is enclosed in the receptacle, with the stamens and other floral parts situated above - perianth and androecium appear to be attached to the upper part of the ovary, due to fusion of the hypanthium to the ovary wall. - inferior ovary

Flower

the reproductive organ of an angiosperm - contains sperm and eggs - a highly modified shoot bearing modified leaves

Carpel

*female reproductive organ* of a flower - consists of the stigma, style, and ovary (which contains ovules) - collectively known as gynoecium

Stamen

*male reproductive organ* of a flower - consists of an anther and a filament - collectively known as androecium

Imperfect flowers

- occur on two types of plant species, monoecious and dioecious - lacks either stamens or carpels

inflorescence

a cluster of flowers on a branch or a system of branches - the mode of development and arrangement of flowers on an axis - a floral axis with its appendages

Radial symmetry

a flower can be divided in *two or more* planes to produce symmetrical halves - actinomorphic (regular)

Bilateral symmetry

a flower can only be divided along a *single* plane in order to produce symmetrical halves - zygomorphic (irregular)

Gynoecium

all of the carpels of a flower - female structures - *site of pollination and fertilization* - stigma, style, ovary (carpel)

Corona

an extra ornamentation found in some flowers - often attractive - outgrowth of perianth, stamens, or receptacle - diverse in form and function

Incomplete flowers

lack one or more floral organs - can be perfect or imperfect - perfect flowers that lack perianth (sepals/petals) - imperfect flowers (unisexual) -> staminate flowers/carpellate flowers

Flowers are evolved and modified _____

leaves

Distinct flowers

like-parts are not fused together

Monoecious plants

male and female flowers on the same plant - have BOTH staminate and carpellate flowers on the same individual plant - most plants are monoecious

Dioecious plants

male and female reproductive structures are on different plants - have only staminate OR carpellate flowers on an individual plant - male and female individuals - marijuana - benefit of seperate gender plants -> forces crossing

Rewards

many flowers offer rewards to pollinators - nectar, oil, fragrance rewards can be produced by various modified structures within the flower (glands) - nectaries

Apetalous flowers

missing petals

Asepalous flowers

missing sepals

Bracts

modified leaves associated with flowers - bracteoles

Asymmetrical flowers

no planes of symmetry

Number of parts

number of floral parts -> taxonomically informative - sepals, petals, carpels, stamens usually easy to count extreme connation may make difficult to count - especially carpels flowers often base on a "plan" - numerous of 3, 4, or 5 - "-merous" -> 3-merous, 4-merous, 5-merous 3-merous -> monocot 4 or 5-merous -> dicot

Anther

part of stamen that *produces and contains pollen* - usually with 4 pollen sacs (2 pairs) ex: microsporangia. Meiosis occurs here -> pollen grains (i.e. microgametophyte) - the pollen sacs = microsporangia, the pollen grains = microgametophytes - connective - Anther opens to release pollen grains (taxonomically informative). Longitudinal stilts (common), transverse stilits, pores, valves

Perigynous

sepals, petals and stamens are fused at the base to form a cup-shaped structure called a *hypanthium* which is inserted beneath the ovary. - a cuplike or tubular structure surrounds the gynoecium, without being adnate to it. - perianth and androecium are attached to the rim - hypanthium: floral cup - superior ovary

Hypogynous

sepals, petals, and stamens are attached to the receptacle below the ovary. the ovary in this case is said to be superior. - perianth and androecium are attached below gynoecium - superior ovary

Bracteoles

small bracts located under the pedicel

Pedicel

stalk of a single flower

Peduncle

stalk of an inflorescence

Receptacle

stem (axis) to which floral organs are attached - floral axis (modified shoot) - may be tiny -> elongate

Androecium

the stamens of a flower collectively - comprised of anther and filament (a stamen) - sometimes petal-like - male structure

Free flowers

unlike-parts are not fused together

Tepal

when a distinction between petals and sepals cannot be made