TRIDAX PROCUMBENS AS BIOLOGICAL SPECIMEN.

Type of plant

Tridax procumbens is an Angiosperm (flowering plant) and a creeping plant/runner/ strangling plant

It is perennial because the life cycle goes beyond two years, continues flowering and fruiting each year

Tridax is also an herbaceous plant because it has a non-woody stem and a dicotyledonous plant

It is a farm weed and an invasive plant.

Biological Classification.

• Class Dicotyledoneae

Reasons

• Presence of taproot
• Presence of leaf stalk
• Leaves have net venation
• Presence of broad leaves
• Possess floral leaves in five parts

Observable features in Tridax

• Possesses a simple leaf
• Leaves have an opposite arrangement
• Possess serrated leaf margin
• Net venation of leaves
• Hairy leaves
• Hairy stem
• Leaf possess stalk
• Presence of axillary and terminal buds
• Branched stem
• Presence of strangling stem/creeping stem
• Nodes present
• Internodes are also present
• Adventitious roots at nodes
• Taproot and lateral roots
• Presence of inflorescence
• Capitulum: a collection of many small flowers or florets
• Possess long peduncle/flower stalk
• Have pappus (calyx reduced to pappus)

Observable characteristics in Tridax

• Presence of broad leaves
• Leaves have net venation
• Presence of leaf stalk
• Possess a taproot system
• Possess floral leaves in five parts

Adaptive features of Tridax to its habitat.

• Hairs on leaves and stems reduce transpiration
• Numerous tiny flowers grouped to bring insects for pollination
• Fruits with feathery calyx (pappus) for wind dispersal
• Coloured flowers for insect pollination
• Long peduncles carry fruit higher to catch air currents for wind dispersal
• The creeping stem enables it to colonise bare soil quickly
• Adventitious roots (numerous) to prevent being carried away by strong wind

Features/characteristics of ecological importance in Tridax

• Fruits have pappus which helps in wind dispersal of fruits.
• The presence of pappus and light weight make it easy for fruits to be carried by wind to be dispersed to different places.
• This reduces overcrowding, competition, intense destruction by herbivores increases chance of survival.
• Hairs on leaves and stems trap humid air, thereby reducing water loss through transpiration.
• Thus, enabling the plant to live successfully in the grassland
• Numerous tiny flowers grouped to bring insects for pollination.

Describe the reproductive structure of Tridax

• Reproductive structure made up of tiny flowers called florets, which are clustered to form a dense head of inflorescence called a capitulum
• Capitulum is a special inflorescence in which florets are clustered to form a dense head.
• Long peduncles carry an inflorescence/capitulum (numerous tiny flowers grouped to bring insects for pollination)
• Coloured flowers which enhance insect pollination

Economic importance of Tridax

• Primary producer in the feeding relationship in the ecosystem.
• Food for herbivores
• Medicinal
• Weed to farm crops
• Fruits carried long distances by wind invade the roadside, crops, homes, and gardens.
• It checks erosion
• Oxygen and carbon dioxide are replenished/recycled in the ecosystem.

Type of pollination

• Cross-pollination

Reasons:

• Stamens mature before stigmas (it is a protandrous flower).

Agent of pollination

• Insects

Reason:

• Possess coloured petals/Florets
• Nectar
• Sweet scent
• Pollen is fairly abundant

Agent of dispersal

• Wind

Reason:

• Presence of pappus
• Light fruits
• Dry fruits
• Small fruits and seeds

Leaf classification in Tridax

• Arrangement on stem: opposite
• Type: simple
• Shape: ovate
• Margin: serrate
• Tip: acute
• Base: cuneate
• Venation: net

A drawing of the upper surface of the leaf of Tridax.

Features of biological significance in the leaf of Tridax sp.

• Serrated leaf margin reduces the rate of transpiration
• Green leaf for photosynthesis
• Hairy to reduce the rate of transpiration

Describe pollination in Tridax

• Cross-pollination because it is protandrous (stamen matures before the stigma)
• Insects are attracted by coloured petals, sweet scent, and nectar
• Insects visit the flower to feed on nectar
• To collect nectar, the body of an insect becomes dusted with pollen grains;
• An insect/butterfly carries a pollen grain to another flower, whose stigma is mature;
• In an attempt to collect more nectar,
• The stigma makes contact with the insect’s body,
• Brushing up some of the pollen grains from the previously visited flower
• Leading to pollination.

Describe dispersal in Tridax.

• Tridax is dispersed by wind
• Mature fruits are small and light in weight
• Presence of pappus
• Carried by the wind to be dispersed

Differences between Tridax and Fern

Similarities between Talinum and Tridax.

• Simple leaves
• Terminal flowers
• Green stem
• Branched stem
• Soft stem
• Net venation of leaves
• Nodes and internodes are present
• Presence of terminal buds
• Presence of lateral buds
• Flower buds

Differences between Talinum and Tridax.

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