19/06/2013 - Plant Identification Unit 20574

On 19/6/2013 we have Field Trip in Botanic Lower Garden at Opoho Road House at 9am with Lisa Burton. The trip was cancelled due to wet and rainy day.

At 1.00pm the class was conducted by Lisa Short on Plant Identification. She was conducting on the topic of Flowers. An important identifying feature of plant is the flower. Flowers are arranged in the way of their appearance  and when they are produced. Flower appearance follows the arrangement of flowers. Flowers are said to be solitary when the plants bears only one or single flowers appear to ends the lateral branches that are remote from one another. 

The inflorescence of a shrub with one flower in each leaf axil on many shoots is often describes as flowers solitary in the axils of the leaves". An inflorescence is a flowering shoot that carries more than one flower. The stem holding the whole inflorescence is called a peduncle and the main stem holding the flowers or more branches within is called rachis. The stalk of each single flower is called a pedicel.

Flower arrangement (phyllotaxis) - Flowers are arranged on the stem in many different patterns :-

1] Opposite Flower pattern

2] Alternate Flower pattern

Terminal Flowers - Inflorescences have two different growth pattern called indeterminate and determinate. This indicates whether a terminal (end)  flower is formed and where the flowering starts within the inflorescence:- 

1] Indeterminate inflorescence - which the terminal bud keeps growing and forming lateral flowers. A 

    terminal flower is never formed.

2] Determinate inflorescence - which the terminal bud forms a terminal flower and then dies out. other 

    flowers then grow from the lateral bud.

Raceme like (racemose) inflorescences:-

These inflorescences are characterised by a pattern of branching where the main axis continues to grow, producing lateral buds, which becoming flowers or shoots that repeat the same pattern. The youngest buds are nearest the top or apex of the main axis.

1]  Spike - is an unbranched inflorescences, able to elongate, with stalkless flowers. Those at the base 

     open first.

2]  Raceme - is an unbranched inflorescences, able to elongate, with stalked flowers. Those flowers at 

      the base open first.  

3]  Umbel - a flat topped inflorescences with all the pedicels arising from a common point at the apex 

     of the main axis. Often umbrella-shaped.

4]  Capitulum - a head like inflorescences of a large number of usually stalkless flowers. Most flowers

     in the Asteraceae family have this type of inflorescences.

5]  Corymb - a flat-topped or domed inflorescences where the outer flowers open first. Corymbs may 

      be simple or compound. 

6]   Panicle - a branched inflorescences, able to elongate, where the branches are usually raceme like or 

      corymb like.

Cyme inflorescences the growth of the main axis is terminated by a flower. One or more lateral buds behind that flower then develop until their growth is in turn stopped by the production of flowers. Cyme a flower terminates each branch, the oldest in the centres.

Finally on some other inflorescences types - 

Catkin is a spike or spike-like inflorescence, usually unisexual flowers on a pendulous axis.

Spike is a spike like inflorescences with a thick fleshy axis, usually surrounded by a large bract (modified leaf).

Today's climate was wet and raining. Temperature was 5 degrees Celsius and Humidity : 64%.