AP BIOLOGY

Detailed explanation-1: -On the basis of presence or absence of specialized vascular tissues, plants are classified into two groups. They are, Non-vascular plants – Thallophyta and Bryophyta. Vascular plants – Pteridophyta, Gymnosperms and Angiosperms.

Detailed explanation-2: -Not all plants have vascular tissues. They are primarily in higher plants such as ferns, angiosperms (flowering plants) gymnosperms (non-flowering plants). The food and water in non-vascular plants are transported through other tissues such as parenchyma cells.

Detailed explanation-3: -Nonvascular Plants. Nonvascular plants (often referred to collectively as the bryophytes) include three groups: the mosses (Bryophyta), approximately 15, 000 species; liverworts (Hepaticophyta), approximately 7500 species; and hornworts (Anthocerophyta), approximately 250 species (Table 1).

Detailed explanation-4: -Plant divisions classify plants based on whether they reproduce by spores or seeds. Spore-bearing plants include ferns, club mosses, and horsetail. Seed-bearing plants are divided into gymnosperms and angio-sperms. plants that produce naked seeds.

Detailed explanation-5: -Vascular plants are also known as tracheophytes. They are grouped under the subkingdom Tracheobionta of the Plant Kingdom. Tracheobionta includes pteridophytes and all the seed-bearing plants called spermatophytes. Spermatophytes contain gymnosperms and angiosperms.