NEET BIOLOGY

Detailed explanation-1: -Lycophytes are seedless vascular plants with sporophytes that have microphylls and branch dichotomously. Sporangia are produced in strobili. Some are homosporous (e.g. Lycopodium), while others are heterosporous (e.g. Selaginella). Ferns and horsetails are homosporous seedless vascular plants that produce megaphylls.

Detailed explanation-2: -The lycophytes are the oldest of the seedless vascular plants that have living representatives. They constitute one of the two major lines (clades) of vascular plants, which split probably in the Silurian Age, but at least by the Devonian.

Detailed explanation-3: -Modern-day seedless vascular plants include club mosses, horsetails, ferns, and whisk ferns.

Detailed explanation-4: -Lycopodium is a genus of club mosses while Selaginella is a genus of spike mosses. Lycopodium plants are homosporous; hence they produce only one type of spores while Selaginella plants are heterosporous; hence they produce two distinct types of spores. So, this is the key difference between Lycopodium and Selaginella.

Detailed explanation-5: -Figure 6.1. 1. 5: A cross section through a Lycopodium root. There is vascular tissue organized in the center with three columns of xylem (A) and phloem (B) between them.