Refer to the given characteristics of some flowers:
I. Flowers are small. They are often packed in inflorescence.
II. Flowers are colourless, nectarless and odourless.
III. Well exposed stamens.
IV. Pollen grains produced in large number, light and non-sticky.
V. Flowers often have a single ovule in each ovary.
VI. Stigma large, often feathery.
The above features are the characteristics of