Green_Plants_Concept_3
Non-Flowering Plants
Non-Flowering Plants
Even flowering plants don't always need to use flowers to make more of themselves. There are several other methods: bulbs (daffodils, tulips), tubers (potatoes), corm (croci), trailing plants (spider plants, strawberries), and cuttings (geraniums). Each of these methods produces a genetically identical copy of the original plant.
Conifer trees and shrubs avoid the need for flowers altogether. This form of plant fife developed long before the flowering plants, and is still going strong. Like flowering plants, conifers produce seeds that (once fertilised) contain an embryonic plant and a store of food. These seeds are not produced within an ovary, however. Conifers are defined by their production of cones — woody fruits within which the seeds develop, A cone, which can take a few years to form, produces a seed at the base of each of its 'fingers'. When these seeds mature, and the weather conditions are favourable, the cone will open up and allow the wind to disperse the seeds.
Pines, a sub-group of the conifers, produce two types of cone: male and female. The male cones, which are relatively small, develop on the lower branches in groups of up to 50. They mature in late spring, releasing their pollen into the wind, then shrivel up and drop off . The female cones grow higher up in the same trees, singularly or in small groups, and are about five times the size of the male cones, The pollen from the male cones is blown upwards by the wind and into the female cones,
Once the eggs are fertilised, the female cones close up to let the seeds develop; this can take up to three years. In this time, the cone becomes woodier as it turns from green to brown. Once they are mature, the seeds are released into the wind to be dispersed Alternatively, small animals may break open the cones and take the seeds, eating some and storing the rest, Often the animal will not return to its store of seeds, giving them the opportunity to grow.
Children need to realise that flowers are not always necessary for plants to reproduce. Even some flowering plants do not need to reproduce from flowers. This knowledge will help them to understand how our food is grown, and how pine trees have survived in cold climates.
Bulb — a swollen, layered stem base from which regrowth is possible.
Cone — a woody 'fruit' with scales that protect the seeds.
Conifer — a cone-bearing tree or shrub.
Tuber — a swollen root from which regrowth is possible.
The Great Basin Bristlecone pines in the USA are the oldest known living things on the planet Some of these trees are over 5000 years old.
39 members of a family of pine trees that was thought to have been extinct for 50 million years were discovered not far from Sydney in 1994,
Conifers only grow in cold countries.
Yes, some do. But there are other types of conifer that grow in hot, dry countries. The cedar grows in the Middle East, North Africa and Northern India — often in hot, dry, mountainous regions where its cones protect the seeds from damage due to heat and lack of water.
Cone collection (observing, sorting)
Ask the children to collect cones from forest floors when they are on holiday or out walking. NB They should only take cones that have fallen to the ground. In the classroom, compare some of the cones together. The children can break open some common types of cone to discover the seeds, and try to work out what type of tree each cone came from.
Cut and run (testing, observing)
Ask the children to talk to their parents about taking small cuttings from plants in their home or garden to grow at school. Which plants grow most easily from cuttings? (Most good gardening books will provide full details on the use of cuttings.) The most important thing to remember is to suspend the end of the cutting in water; poking it through cling film stretched over a container of water is an effective method. The children could also talk to their parents about plants with runners (creeping stems that can take root separately from the main plant) in the garden — strawberries are a common example.