HiSET Science: Characteristics of Major Plant Divisions

Vascular and Nonvascular Plants
Vascular plants, also referred to as tracheophytes, have dermal tissue, meristematic tissue, ground tissues, and vascular tissues.
Nonvascular plants, also referred to as bryophytes, do not have the vascular tissue xylem and phloem. Vascular plants can grow very tall, whereas nonvascular plants are short and close to the ground. Vascular plants can be found in dry regions, but nonvascular plants typically grow near or in moist areas. Vascular plants have leaves, roots, and stems, but nonvascular plants have leaf-like, root-like, and stem-like structures that do not have true vascular tissue. Nonvascular plants have hair-like rhizoids, that act like roots by anchoring them to the ground and absorbing water. Vascular plants include angiosperms, gymnosperms, and ferns. Nonvascular plants include mosses and liverworts.

Flowering Versus Nonflowering Plants
Angiosperms and gymnosperms are both vascular plants. Angiosperms are flowering plants, and gymnosperms are non-flowering plants. Angiosperms reproduce by seeds that are enclosed in an ovary, usually in a fruit, while gymnosperms reproduce by unenclosed or
'naked' seeds on scales, leaves, or cones. Angiosperms can be further classified as either monocots or dicots, depending on if they have one or two cotyledons, respectively. Angiosperms include grasses, garden flowers, vegetables, and broadleaf trees such as maples, birches, elms, and oaks.

Gymnosperms include conifers such as pines, spruces, cedars, and redwoods.


Monocots and Dicots
Angiosperms can be classified as either monocots or dicots.
The seeds of monocots have one cotyledon, and the seeds of dicots have two cotyledons. The flowers of monocots have petals in multiples of three, and the flowers of dicots have petals in multiples of four or five. The leaves of monocots are slender with parallel veins, while the leaves of dicots are broad and flat with branching veins. The vascular bundles in monocots are distributed throughout the stem, whereas the vascular bundles in dicots are arranged in rings. Monocots have a fibrous root system, and dicots have a taproot system.