8 Difference Between Homosporous Pteridophytes And Heterosporous Pteridophytes

What Are Homosporous Pteridophytes?

Homosporous pteridophytes are vascular plants which produce spores of one kind. The spores of these plants cannot be differentiated as male or female. The spores of homosporous plants grow into bisexual gametophytes, producing both male and female gametes. The fusion of the gametes forms the embryo, which develops into the sporophyte

In most homosporous pteridophytes, the spores are both morphologically and physiologically identical and produce bisexual gametophytes. In some species of horsetail (Equisetum), the spores may be physiologically different and produce male or female gametophytes. . Generally, in homosporous pteridophytes, the spore results in monoecious gametophyte which bears both male and female parts (antheridia and archegonia respectively) in the same plant.

Examples include:

• Club moss
• Lycopodium
• Puzzle grass
• Equisetum
• Whisk ferns
• Psilotophyta
• Phylloglossum

Characteristics Of Homosporous Pteridophytes

• These pteridophytes produce only a single type of spores.
• Spores are generally small in size.
• The spores are not separated by sex.
• Spores are equal in size.
• Produce only one type of gametophyte.
• Gametophyte is bisexual.
• The spores are produced from the same sporangia.

What Are Heterosporous Pteridophytes?

Heterosporous pteridophytes produce two types of spores which differ in size or morphology. The two types of spores are referred to as the microspores and megaspores (male and female spores respectively).

Microspores are produced from the microsporangia and they develop into male gametes. Megaspores on the other hand, are produced from megasporangia and develop into female gametes. Generally, the microspores are smaller in size whereas megaspores are larger in size. More importantly, microspores are high in number whereas megaspores are less in number.

Megaspores produce the female gametophyte that bears Archegonia whereas the microspores produce male gametophyte that bears antheridia. The resulting plants are thus dioecious.

Examples of Heterosporous pteridophytes include:

• Salvinia
• Marselia
• Selaginella
• Azolla
• Isoetes

Characteristics Of Heterosporous Pteridophytes

• These pteridophytes produce two types of spores (the microspores and megaspores).
• Spores are generally small microspores and large macrospores.
• The spores are separated by sex.
• Spores come in two different sizes. The smaller spores are referred to as microspores and large spores are referred to as megaspores.
• Produce two types of gametophytes: male and female gametophyte.
• Gametophyte is unisexual.
• The microspores are produced from the microsporangia whereas the megaspores are produced from the megasporangia.

Difference Between Homosporous And Heterosporous Pteridophytes In Tabular Form