Division: Magnoliophyta
(Flowering plants)

Class: Magnoliopsida (Dicotyledons)
Asteraceae (Sunflower)
Berberidaceae (Barberry)
Caprifoliaceae (Honeysuckle)
Oleaceae (Olive)
Aceraceae (Maple)
Polemoniaceae (Phlox)
Fabaceae [Leguminosae] (Pea)
Chenopodiaceae (Goosefoot)
Hydrangeaceae (Hydrangea)
Onagraceae (Evening Primrose)
Ericaceae (Heath)
Rosaceae (Rose)
Salicaceae (Willow)
Saxifragaceae (Saxifrage)
Betulaceae (Birch)
Class: Liliopsida
Poaceae [Gramineae] (Grass)
Cyperaceae (Sedge) 

Division: Magnoliophyta
    The division Magnoliophyta (Anthophyta) , the flowering plants, are believed to be the most recently evolved and the most successful plants on earth. They compose the largest groups of plants with vascular tissue (water conducting tissue composed of xylem and phloem) in number of individuals and in diversity as shown by the number of genera and species. There are approximately 300,000 species of flowering plants grouped into approximately 12,000 genera. Flowering plants include trees, shrubs, herbs, vines, floating plants, epiphytes, and even parasites which do not have chlorophyl. They can be found in almost all habitats–xeric, mesic, and hydric. They comprise the dominant portion of the vegetation most areas. Their life cycles include annuals, biennials, and perennials. They may be evergreen or deciduous. The perennials include woody types with secondary growth such as trees, shrubs, and vines. Perennial herbaceous types without secondary growth survive dormancy periods such as dry seasons or winter by corms, bulbs, rhizomes, or other underground organs such a woody caudex.
The following is an abbreviated summary of flowering plant anatomy. For more details, studying any general botany or plant anatomy or morphology book is suggested.
A flowering plant normally consists of roots, stems, leaves, and reproductive parts. It begins its life as an embryo within the seed. The embryo has a terminal bud at one end and a primary root or radicle at the opposite end. Seed leaves (cotyledons) are attached at a midpoint which divides the stem from the root. The area below the attachment point of the cotyledons is called the hypocotyl and the region above is termed the epicotyll. Roots which branch from the radicle are called secondary roots. Roots which arise from anywhere else on the plant, usually from somewhere on the stem, are called adventitious roots.
The leaves of flowering plants are termed macrophyllous (macro = large, phyllous = leaves). However they vary greatly in size. Palm leaves my be several feet in length while those of cacti and spurges may be almost microscopic. Stems are roughly divided into regions called nodes and internodes. Leaves arise from nodes . If only one leaf arises from each node, it is referred to as alternate leaf arrangement. They appear to be spiral up the stem. If two leaves arise from a node, the condition is referred to as opposite leaf arrangement. If three or more leaves arise from the node, it is referred to as whorled leaf arrangement. The angle formed by the leaf stalk (petiole) is referred to as the leaf axil. In this axil, there is usually a bud which is referred to as the axillary or lateral bud. It normally has the potential to become either a branch or an inflorescence or rarely a spine. The flat portion of a leaf is referred to as the blade. If it is undivided, it is a simple leaf. Its edges are called the leaf margin which may be toothed (dentate), serrate, or lobed. If the blade is divided all the way to midrib, it is referred to as a compound leaf. There are two types of compound leaves. If the divisions come off the midvein as the divisions come off a feather, the leaf is referred to as pinnately compound. If the divisions all appear to come off one point at the tip of the petiole radiating outward, it is a palmately compound leaf. Some plants have two lateral appendages attached to the stem at the base of the petiole. These are stipules. In some families such as in some of the spurge family members or some pea family members, they may be spines rather than leaf-like.
The veins in leaves may be parallel as in the Liliopsida or they may form a network as in the Magnoliopsida. Rarely they may be dicotymously branched. A cross section of a leaf reveals epidermis on both the adaxial and abaxial surfaces. Between these two layers lies mesophyll which is usually divided into two regions. The orderly arranged portion usually adaxial is palisade mesophyll while the less orderly cells are called spongy mesophyll. Chlorophyll is located in the mesophyll, but not in the epidermis. Openings in the epidermis which allows for gaseous exchange including loss of water vapor are called stomata. They have specialized cells which open or close called guard cells. The veins or vascular bundles contain both xylem and phloem. Sometimes the xylem and phloem are surrounded by specialized, often thick walled cells called the bundle sheath. Leaves do not just break off anywhere, but there is a special region which breaks easily called the abscission layer. This also is so constructed that it prevents loss of fluids.
The stems of flowering plants vary. They may be erect, decumbent, prostrate, or climbing. Stolons are prostrate on the substrate surface. Rhizomes are horizontal below the ground. Underground stems also include tubers, bulbs and corms. Underground parts may be woody having secondary growth or soft having no secondary growth. Xylem vessels are found in all but a few (100 or so) species. These contain no cytoplasm when they function to conduct water from the roots upward in the stem. The phloem contains companion cells adjacent to the sieve cells. Sieve cells contain cytoplasm, but have no nucleus. Stems branch by the growth of the axillary buds which are located on the stem surface.
In the dicots (Magnoliopsida) the emergent radicle my persist as a deep-growing taproot. In many monocots (Liliopsida) such as grasses, the radicle may stop growing and the subsequent root system is composed entirely of adventitious roots. Roots do not have nodes and internodes as stems do. Roots branch from the pericycle layer at any location, not from a surface located axillary bud as in stem. To differentiate between rhizomes and roots, one can find nodes from which scale-like remnants of arise. In their axils, the axillary buds my give rise to vertical stems. Adventitious roots also come from the nodes. The nodes are separated from each other by internodes just as in above ground stems. The branches of roots appear to arise randomly from any location.

Class: Magnoliopsida (Dicotyledons)

Class: Liliopsida

Information by Dr. Karl E. Holte, ©2001.