Question

Comment on diversity of Pteridophytes plant groups.​

Answer 1

Answer:

Lycopodiopsida, or lycophytes have at least four genera and more than 1,200species. Lycophytes belong to microphyllous lineage of pteridohytes. This means that their leaves originated from the emergences of the stem surface, and therefore are more similar to moss leaves than any other leaves of pteridophytes and seed plants. Lycophyte sporangia are associated with leaves and often form strobilus which is a condensation of sporangia-bearing leaves (sporophylls when they are leaf-like or sporangiophores when they are divergent). Their spermatozoon usually has 2 flagella (like mosses) but are sometimes also mul-tiflagellate (like spermatozoa of other ferns). Lycophytes used to be the domi-nant plants of Carboniferous tropical swamp forests and their remains became coal. Contemporary lycophytes are much smaller but still thrive in wet and warm places. More basal lycophytes (clubmosses Huperzia and Lycopodium) have equal spores and underground gametophytes, whereas more advanced Selaginella (spike-moss) and Isoëtes (quillwort) are both heterosporous (see below) with reduced aboveground gametophytes. Quillwort is a direct descendant of giant Carbonif-erous lycophyte trees, and despite being an underwater hydrophyte, it still re-tains the unusual secondary thickening of stem. Many spike mosses are poikilo-hydric (another similarity with mosses).

Answer 2

Pteridophytes

Explanation:

• Pteridophytes lack flowers or seeds.
• They are called cryptogams.
• They include ferns, horsetails and lycopods.
• They are considered as the first terrestial vascular plants, showing the presence of the vascular tissue , xylem and phloem.
• they are classified into psilopsida , lycopsida, sphenopsida,pteropsida