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FM-AA-CIA-15 Rev. 0 10-July-2020
PANGASINAN STATE UNIVERSITY
Study Guide in BIO 114: TAXONOMY OF CRYPTOGAMS
STUDY GUIDE 24
GENERAL CHARACTERISTICS OF PTEROPSIDA
PTEROPSIDA
Prepared by: Navat, Paulo Jay; Deang, Ma. Isabel; Nacorda, Joy
TOPIC OVERVIEW
Geologically ferns have been known since the carboniferous period. It is believed, however, that the group
must have had its ancestors during the Devonian period itself. A unique feature of ferns is that their persistent
basic characters are still sufficiently plastic to be receptive to the environmental fluctuations. Pteropsida are
distinct from lycopsida and sphenopsida in several characters. Among the vegetative characters, the
megaphyllous leaves with the attendant leaf gaps are most notable. Among the reproductive features, (though
some primitive members show some sort of a semblance to the strobilar organisation seen in the previous
groups), the aggregation of sporangia on the abaxial or adaxial surface of the leaf into sori is the most significant.
LEARNING OUTCOMES
At the end of this Module, you should be able to:
1. Acquaint with the basic characteristics of the Pteropsida
2. Determine the basic morphology and physiology of the different parts of Pteropsida
3. Determine the major taxa under the different subdivisions of Pteropsida
5. Explain the importance of Pteropsida
It includes the plants which are commonly known as ‘ferns’. It is represented by about 300 genera
and more than 10000 species.
1. They occur in all types of habitats. Majority of the ferns are terrestrial and prefer to grow in moist
and shady places. Some are aquatic (e.g., Azolla, Salvinia, Marsilea), xerophytic (e.g., Adiantum
emarginatum), epiphytic (e.g., Asplenium nidus), halophytic (e.g., Acrostichum aureum) or climbing
(e.g., Stenochlaena).
2. Majority of the members (except some tree ferns (e.g., Angiopteris) have short and stout rhizome.
The rhizome may be creeping, upright or growing above the soil.
3. Leaves are large, may be simple (e.g., Ophioglossum) or pinnately compound (majority of the ferns
for example, Pteridium, Marsilea, Adiantum etc.) and described as fronds. Young fronds are
circinately coiled.
4. Leaves are ex-stipulate (e.g., Filicales) while stipulate in some other groups.
5. The vascular cylinder varies from a protostele to a complicated type of siphonostele. Solenostele,
dictyostele and polystele are also found.
6. Vegetative reproduction takes place by fragmentation (e.g., Adiantum, Pteridium), stem tubers e.g.,
Marsilea), adventitious buds (e.g., Asplenium bulbiferum) or by apogamy (e.g., Marsilea).
7. Sporangia arise from placenta (a swollen cushion of cells) in groups (sori).
8. Sori develop on the margins or abaxial surface of the leaves (sporophylls) or leaflets.
9. Sori are protected by true (e.g.Marsilea) or false indusium (e.g. Adiantum, Pteris)
10.The sporangial development may be leptosporangiate (e.g., Osmunda) or eusporangiate type
(e.g., Ophioglossum).
11. The sporangia in most cases have a distinct annulus and stomium.
12. Members may be homosporous (e.g., Pteris, Adiantum etc.) or heterosporous (e.g., Marsilea,
Azolla, Salvinia etc.).
13. The gametophyte may be exosporic or endosporic.
14. Antheridia and archegonia are partially or completely embedded in the gametophyte.
Antherozoids are multi-flagellated.
15. Embryogeny largely endoscopic. Embryo may or may not have suspensor
