Non-vascular plants have been on planet Earth longer than their vascular cousins. Since they have no internal means to transport water within their structures yet still depend heavily on moisture for survival, non-vascular plants have some plant parts that are unique.

Land Pioneers

Non-vascular plants were the first to venture on to the land. To do this, they needed to develop a means to keep their tissues from drying out. The answer was to form waxy cuticles and organs with a protective covering that would help retain water.

Mini Roots

Once on land, non-vascular plants developed rhizoids. These are root-like structures that help keep them attached to the surface they are growing on. Though not true roots, these tiny structures also absorb water.

Microphylls

Green plants have chlorophyll in their leaves that they use for photosynthesis. This is the conversion of water and carbon dioxides to sugars and oxygen. Most non-vascular plants have microphylls, small bits of tissues on the stems that take the place of leaves. Photosynthesis takes place in the microphylls.

Generational Structures

Plants have two generations in their life cycle, a sexual phase and an asexual phase. In non-vascular plants, the sexual phase, called the gametophyte, is the dominant stage. The asexual phase, the sporophyte, takes its nutrients from the gametophyte.

Reproductive Structures

Most non-vascular plants reproduce using spores. Once dispersed, usually by wind or water, the gametophytes grow producing both female sex organs, the archegonia and male sex organs called the antheridia. The male sperm is equipped with flagella, which allow it to swim to the female egg once sufficient water is present. Some forms of algae produce asexual spores that do not require fertilization.

Source:

Cartage.org: Non-vascular Plants

CWSS.org: Biology of Non-vascular and Lower (Seedless) Vascular Plants

TheKidsGarden.com: Teaching Kids About Photosynthesis