The class of lycophytes and group features of lycophytes is a vital subject for botanists. Lycophytes are spore-bearing vascular plants comprising more than 1,200 extant species. The phylum lycophyta is the oldest of the seedless vascular plants and evolved more than 400 million years ago. The three classes of lycophytes are the club mosses (Lycopodiales), the quillworts (Isoetales), and the spike mosses (Selaginellales). For instance, the three divisions have varying growth forms. Regardless of their size or geologic age, all share certain group features. Subsequently, the group features of lycophytes includes their structures. In conclusion, lycophytes are primitive plants lacking seeds, wood, fruit, and flowers.
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THE STRUCTURE AND GENERAL FEATURES OF LYCOPHYTES
The group features of lycophytes are similar aspects of the three classes. First, branching is usually dichotomous. Thus, the shoot tip forks repeatedly. The two branches that result may be equal or of different lengths. Secondly, each leaf is narrow and has an unbranched midvein. Fourthly, the sporangia occur singly on the adaxial of the leaf. Fifthly, the classes of lycophytes bear cone-like structures called strobili, which are tight aggregations of sporophylls. Fifthly, the stem is protostelic, but there is great variety in the disposition of xylem and phloem. Sixthly, all lycophyte plants are herbaceous. Lastly, lycophytes have two alternating generations and are both wind-pollinated and dispersed. Despite the similarities, the life cycle of lycophytes varies.
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THE ORDERS AND CLASSES OF LYCOPHYTES
There are three classes of lycophytes. First, the club mosses include around 400 species. The vast majority of species belong to the genus Huperzia. Secondly, the spike mosses constitute a single genus Selaginella, with 700 species. Spike mosses grow on other plants as epiphytes and the forest floor. Lastly, the quillworts consist of around 150 species belonging to the genus Isoetes. Notably, the life cycle of lycophytes varies. Therefore, club mosses produce one type of spore, whereas quillworts and spike mosses produce distinct male and female spores. Moreover, club mosses and spike mosses grow adventitious roots, while quillwort roots grow from the base of their underground stem. In conclusion, the group features of lycophytes vary with the individual characteristics of the classes.
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