Plant Basic biology -4  Flowers


The fourth page on how plants live and thrive

This is the fourth page on how plants live and thrive. The first Plant, Basic Biology-1 {roots and rhizome} We looked at the different types of roots and their functions. In the second Plants,Basic Biology -2 we reviewed the leaves and their functions which continued in Plants, Basic  Biology-3. Now it is the turn of the flower also referred to as Blossom, or Blooms.

Many components make up the flower as will be revealed. Once again an attempt will be made to keep the text as uncomplicated as possible. However, some botanical terminology is unavoidable.



The most obvious part of the flower  { but not always} is the one that attracts the eye and often has one standing in admiration--the petals and their colour.They are often brightly coloured and/or/ of unusual shapes, which draw the eye to their beauty. Although we benefit from this natural beauty, indeed, nursing and nurturing them until we are rewarded with their beauty. It is not for our sakes that they do so. All this colourful gaiety is for the purpose of attracting pollinating insects of the insect fraternity and other invertebrates, in order that the species will set seed and reproduce others of their ilk.

Bees are important pollinators

photograph by Dal

Botanical terms

Many readers, { with the exception of knowledgeable plants men} will have come across the word corolla within the text of flower books, regardless of the plant being a cultivated variety or wild flora, without knowing exactly what it is.

Together all the petals of the flower are referred to as the corolla. The word comes from the Latin corolla meaning a garland from corona meaning a crown. Incidentely the word petal derives from the Greek word petalon meaning a leaf. { Indeed petals are modified leaves.}

Some corollas are fused together to make a tube as in some species of fuchsia, others form lobes at the opening which defines the corolla petals from the tube.

Some corollas are fused together to form a corolla tube

photo Dal

The corolla---

The corolla {petals} extend outwards from the calyx {see below} nestled within these structures are anthers, stamens and stigma. These and their functions are reviewed later in the text.

Petals often grow with another set of modified leaves called sepals which are often located just below the corolla. In the case of many species of buttercups for instance they clasp the petals from below . They are more often than not a different shape and colour from the petals, thus are easily distinguished. however, this is not always the case some species such as the wood anemone have sepal like  petals. When petals and sepals of a flower look similar they are referred to as tepals.

Wood anemone have sepal like petals termed as tepals.

photograph -Dal


The sepals together are called the calyx which derives from the Greek word Kalux meaning a shell from kaluptien meaning to cover or to hide. The calyx {sepals} and the petals {corolla} together from what is referred to as the perianthe  from the Greek peri-indicating around or near + anthos  a flower.

Sepals  on different flower species vary and can appear much smaller, awn like, scale like or similar to teeth. One function of the calyx {sepals} is to enclose the flower when in bud to protect the vulnerable softer tissues.

The sepals are protecting this frosted rose bud

photograph by Dal

The less conspicuous parts of the flower

Now we are to review the less conspicuous parts of the flower starting with the stamens {in some plants they are quite visible  protruding from beyond the petals { See photograph below}, each stamen the word derives from the Latin stare meaning to stand, is the main male reproductive organ of the flower. The stamen usually has a stalk known as the filiment from the Latin filum meaning a thread. At the tip of each filiment there resides an anther from the Greek anthos a flower , along with pollen sacs. These sacs contain pollen grains.

The pollen when ready, is released by dehiscence of the anther { dehiscence from the Latin dehiscence from dehiscere meaning to split open from DE-+ hiscere meaning to yawn} the pollen is transported to the waiting carpel of the same flower or indeed another flower, by which pollination occurs. The carpel  is the female reproductive organ of flowering plants which consists of an ovary, style and stigma. The carpels are separate or fused to form a single pistil, carpel is from the Greek  Karpos meaning fruit.

The pollen is transported to the carpel by a variety of means which includes the wind, water, some member of insect land or by merely falling down. Typical flowers have six stamens inside the perianthe { the petals and sepals together} arranged around the carpel. Readers that are interested in the complex types and function of the stamen can obtain this information from books on botany or from specialist web sites. This includes how the anther is attaches to the filaments and the botanical terms for such attachments. Within the confines of this page  it would be impossible to go into every detail and botanical terminology required to do the subject justice.

However, it may be of interest to the reader to note that there are some species of plants that are unisexed, with either all male or all female flower parts. Monoecious means both types of flower occur on the same plant. Dioecious means that the male and female flowers are borne on separate plants thus two types of plants are required for pollination to occur, such plants include nettle and red campion.

Below -top-nettle and bottom red campion are both Dioecious  plants having only one type of flower one each plant


Bascic biology continued

A plant that only has male reproduction parts are known as Androceious from andros meaning man, the flowers with only female parts are referred to as being gynoecious from gyne meaning woman.

The fruit {seed capsules or containers} is the ripened ovary together with the seeds. 

Flower buds

Next under review is the flower bud/leaf bud. The buds of many species and especially those that grow in cold climates are covered with scale like structures which are again modified leaves. Many such scales are protected by viscid substances which protect the internal tissues from inclement weather and from attack by insects and other invertebrates.  a good example is the bud of the horse chestnut.

Other species especially garden annuals lack these scales and are referred to as naked buds. The modified leaves that protect these buds are usually very hairy. As with all parts of a plant or tree the buds have their own terminology attached to them. For example -terminal, suggests these buds are located at the tips of stems or branches. Axillary  buds are located in the leaf axil.

The common ash tree has a terminal bud and two lateral buds one at each side of the twig. these are prominent during the winter months and are a good identifying feature of the ash tree at that time. 

Below the sticky scales give way to the leaf on the horse chestnut. below the terminal and lateral buds of the common ash tree.

photographs by Dal

Buds continued

There are words for the buds status, such as dormant, for morphology such as scaly, naked, hairy etc. Over this series of four, we have reviewed the basic functions, shapes and parts of the living plants and trees. Together these features help them to live and thrive in the location in which they grow.  We have followed the journey of the plants life from germination of the seed, which produces the roots that anchor them into the growing medium. The roots provide the water and other nutrients for the growth that occurs above ground.

We have reviewed the functions, texture and shape of the foliage -the flowers that form the seed, thus our journey has ended where it began. Botany is a subject of immense and complex variation which, would fill volumes to do it justice. Over the series {see associated pages below} I have attempted to bring the very basic  points to the reader so that they {I hope} will have a better understanding of our living flora. 

Associated pages.

Plant basic biology -1    roots and rhizomes

Plant basic biology-2 --foliage

Plant basic biology-3  foliage continued.

Recognizing  winter trees.

Tree flowers.

Tree blossom .