Part 1 - Nonvascular plants - Moss & liverwort

Photos by Dr. Rob Bowker, Glendale Community College, Glendale, Arizona
(These photos are protected by copright and may not be reproduced without written permission.)

The photo shows a typical moss plant.  Sex organs (see below) on the leafy green part of the moss plant (C) produce egg and sperm for fertilization.  The stalk (B) and capsule (A) in the photo grew from a fertilized egg.  Spores are produced inside the capsule and released into the air. A spore is a single cell.  If it falls into a moist protected area, then it can divide and grow into a new moss plant like the one shown here (C).

This photo shows the male sex organs (antheridia) of a moss, as they appear through a microscope using the 40x objective lens.  These structures are found at or near the tips of the stems of the leafy moss plant shown above. Structure A is one antheridium.  There are several others in the picture. Inside A you can see many tiny dark dots crowded close together.  These are sperm cells. The sperm will be released at a time when the plant is flooded with water so that they can swim to an egg cell in the female sex organs (see below).

The photo shows several female sex organs (archegonia) as seen through the microscope.  These structures grow at or near the tip of the leafy stem of a moss plant like the one shown at the top of this page. Structure A is one archegonium.  You can see several others in the picture. You can see one egg cell (B) within a cavity in this archegonium. The egg stays here and is fertilized by a sperm that swims from (most likely) another moss plant. After fertilization, the fertilized egg divides, producing a long stalk and capsule like those on the moss at the top of the page.

This is a liverwort. (see lab handout; you may not need to know this group) Note the thin, flat body of the plant, which is neither leaf nor stem but something in between (called a thallus).  It grows very low and spreading.  An individual plant is only a few inches tall at most. Note the umbrella-like structures.  These bear the gamete-producing sex organs.  (This one is female.) Liverworts are not very closely related to mosses, but they have a similar life cycle and are another group of nonvascular plants.  Like mosses, they must be flooded with water to reproduce sexually, as the sperm have to swim to an egg.