An umbel is a cluster of flowers, in which the flower stalks all spring from the same point like the ribs of an umbrella. Synonymous with cultivar. Each cultivar or variety is genetically different. Examples are 'Hass' avocado, 'Spear' wheat, 'Caliph' barrel medic. A species is a population that is genetically different from others and rarely interbreeds with other species.
Examples are avocado, wheat, barrel medic.
Vase-shaped trees all shoots are headed, shoots in the centre of plant are removed, when main skeleton is built, trees are left unpruned. Vertical axis system natural pyramid shaped tree with minimum pruning.