A person looking to start a new lawn has several options at his disposal. You can plant plugs of grass, which are actually tiny grass plants that spread by putting out runners above the ground and under it. Another option is to lay out a carpet of grass that can spread its roots beneath the soil and begin to grow. But many people who wish to start a new lawn will choose to begin it using grass seed. The production of grass seed is a major industry in its own right. Grass farmers collect seeds as grass plants produce it. The process of producing grass seed is facilitated through sexual reproduction.
As with many plants, grasses can reproduce sexually. The sexual reproduction of grass starts when grass stems, called culms, produce a flowering head. The small flowers that grasses produce are called florets. These florets grow in little clusters which are called spikelets. The florets collectively form a crown known as an inflorescence. As with most flowers, the florets of grass have both male and female parts. The male parts produce pollen spores that fertilize the female parts, which are known as pistils. The pistil has a small, sticky end which is known as the stamen. The stamen is sticky so that it will trap pollen when the pollen brushes up against it. The pollen from the florets is carried by the wind to other flowers to fertilize them at the stamen. Once the pollen is trapped by the stamen, a pollen tube forms in the pistil to connect the stamen to the flower's ovary and carry sperm from the pollen to the flower's egg. The fertilized egg forms a grass seed. The seed eventually pushes the flower out and forms on the grass's head. In the spring and summer months, the grass pollen is so adept at being carried by the wind that some people experience allergic reaction to airborne pollen.
If you've never cut your lawn, or you've simply waited too long between cuttings, you have probably noticed that your grass extends seed heads laden with grass seed. On grass seed farms, the farmers regularly allow the grass plants to grow until they produce a seed head of this nature. Then these farmers collect the seed from the seed head for commercial sale.