Perennial species typically have Secondary Growth which is identical to what we saw in the Coniferophyta. The major differences are that the Xylem of Magnoliophyta can have Vessel Members which are more efficient for water conduction, compared to Tracheids. Furthermore, Sieve Tube Members are found in their Phloem. These are more efficient than Sieve Cells which are found in all other vascular plants.

The Roots of Magnoliophyta are similar to those of the Coniferophyta.

They have Multicellular Apical Meristems and  Lateral Branching. They have an Actinostele like most other roots.

Some species have symbiotic relationships with soil microbes that fix Nitrogen. The most famous of these is the legume-Rhizobium symbiosis which has been profoundly important for agriculture. Acacia koa has this kind of symbiosis which doubtless has significant ecological importance. Most species have mychorrizal associations  with soil fungi. These are very important for the absorption of water and minerals from soil.

Some species have specialized prop roots like those seen with Pandanus (hala). Large tropical trees may have root buttresses at the base. These help to support the large aerial portions of the tree. Vines have roots which cling to aerial structures. 

The Stems of Dicots are very similar to those of the Coniferophyta. They have Multicellular Apical Meristems and   Lateral Branching. They have a Eustele and an Ectophloic Siphonostele.

However, Monocots like Sugarcane (Saccharum) have a unique stele that is known across the cosmos as an Atactostele. The Vascular Bundlesin an Atactostele are organized into more than one ring and they can usually be found at the center of the stem.

Monocots like Coconut Palm (Cocos), Ti (Cordyline) & Hala (Pandanus)  have a unique form of secondary growth, but we will not delve into this right now. Take BOT 410 to learn more about this.