The Leaves of the Magnoliophyta are Megaphylls! They range from the simple & minute Duckweed (Lemna) to the large and complex (Palms).

Monstera - A Megaphyll if ever I saw one!  (Monocot)

Simple Megaphyll from Fuchsia  (Dicot)

A Compound Leaf of Sumac  (Dicot)

Taro  (Monocot)

In most cases the Mesophyll is Complex & is specialized for maximal photosynthetic efficiency. It is common to find Palisade & Spongy layers. Some plants have a distinctive arrangement of Photosynthetic cells and Vascular Bundles called Kranz (Wreath) Anatomy. This is associated with C4 Photosynthesis.

Typical Dicot Leaf with Palisade & Spongy Mesophyll

Sugarcane (Monocot) Leaf with Kranz Anatomy

Leaf Venation is generally intricate and net-like.  

Both Dicots and most Monocots have a Network of Veins.

Dicots have Reticulate Venation while Monocots have Parallel (Striate) Venation. A careful inspection of plants with "parallel venation" reveals the fact that their long, parallel veins are interconnected by lateral veins.

Reticulate Venation in Ohi'a Lehua after the removal of its Trichomes (Dicot)

Leaf Skeleton of a Dicot showing Reticulate Venation

Parallel (Striate)  Venation in ki (Cordyline) Monocot

Network of Veins in Maranta, a Monocot with Parallel Venation

Temperate and subarctic species produce hardy Buds which are similar to those we saw for the Coniferophyta. They are composed of tiny modified leaves called bud scales! These protect apical meristems with primordial leaves or flowers during harsh weather. 

Buds are an important adaptation for plants that live in climates with freezing temperatures and extreme aridity.

Vegetative Leaves & Stems produce many different types of Epidermal Hairs or Trichomes. These serve many functions which include the reflection of light, protection from excess evapo-transpiration, protection from herbivores, attraction of pollinators and the capture of prey.

No other group of plants comes close to the Anthophyta when it comes to the production of Epidermal hairs. Their adaptive significance is tremendous!

Trichomes Galore on the Leaf of Kalanchoe

Ohi'a lehua Leaf Lower Surface covered by Trichomes

Ohi'a Lehua Leaf Section showing dense layer of Trichomes (T) on the lower surface and a Thick Cuticle (C) on the upper surface.

Floral Organs are modified Leaves!