No evidence has proven that alien races exist, but if they do they may have plant-based characteristics (i.e. trees, flowers, cacti, etc.).
No, flowers are a parts of a plant. Some plants don't have flowers, but all flowers come from plants.
because there is only a short period of time when the plant is in flower and some plants produce different colored flowers
A seed plant that produces flowers and some kind of fruit is an angiosperm.
plants with sticky stamen, flowers have nectories
well if its a plant then its in the plant kingdom, if it isn't then its not. chloroplasts.
no some oak trees have flowers on them
Venus fly trap
there color and smell is diffrent from certain other flowers.
Umbrella plant, urginea and ursinia are flowers. They begin with the letter U.
Some characteristics of lilacs include long, cone-shaped panicles that are covered in tubular tiny flowers and and flagship purple flowers. You can learn more about this flower at the Wikipedia.
It is because of it's genetic. Every type animals and plants has it's own unique combination of genetic. So some flowers are tall and some short due to this reason.