Plant Biology and Classification

The polycyclic condition is the most complex of stelar organization found among pteridophytes. It is a dictyostele consisting of two or more concentric rings of meristeles. It occurs in Pteridium sp. 

The class Pteropsida is characterized by pteridophytic plants, that have large, dissected leaves and sporangia, that are borne on the leaves. Pteropsida is divided into three classes - (i) filicineae, (ii) gymnespermae, (iii) angiospermae. 

The archegonium of Selaginella is more reduced than that of Funaria, featuring an embedded venter, absence of a stalk, and a very short neck.

Selaginella is characterized by heterospory and the presence of ligules on its leaves.

Like all pteridophytes, the life cycle of Selaginella exhibits alternation of generations where the sporophyte is the dominant, independent, and photosynthetic phase.

The plant body of Selaginella is a sporophyte, which is diploid and produces spores through meiosis.

Selaginella is known to possess pyrenoids in its chloroplasts, which is a unique feature among many pteridophytes.

Heterosporous pteridophytes produce two types of spores (microspores and megaspores). Selaginella and Salvinia are classic examples of heterospory.

Selaginella is heterosporous, meaning it produces two types of spores. Therefore, it does not exhibit homospory.

Lycopsida is a class of Pteridophyta, not Bryophyta. Bryophyta includes classes like Hepaticopsida, Anthocerotopsida, and Bryopsida.

S. rupestris is known for having uniform leaves, exhibiting homophylly, whereas most other Selaginella species are heterophyllous.

Because Selaginella has both microspores and megaspores, the plant is called as heterosporous. The other fern-allies are homosporous (having only one type/size of spore). This significance of this advance in evolution is important because sexual dimorphism is being expressed much earlier in the life cycle. The organisms to appeared next this are all heterosporous.

A resurrection plant is any poikilohydric plant that can survive extreme dehydration, even over months or years. Selaginella lepidophylla, is known as resurrection plant or birds nest moss as it shows ball like appearance (cespitose habit) in dry season. It is a plant species native to North America, Central and South America, and sold as a novelty.

Heterospory means the production of two spores of different sizes and of two different development patterns. Small spore is called microspore and large spore is called megaspore. Microspore produces the male gametophyte that possesses male sex organs while megaspore produces the female gametophyte that possesses female sex organs. It ultimately leads to seed development. For example, Selaginella, Salvinia, Azolla. Dryopteris and Adiantum are homosporous and haploid spores are produced in each sporangium.