Monocot Leaves

The grasses are the most economically important of the plant families, these monocots include wheat, barley, oats, timothy, rice, wild rice, common lawn grasses, sugar cane, and corn (maize) as well as many other forage and wild grasses. There are over 5,000 species in about 525 genera. The three leading world crops - wheat, rice, and maize - alone account for about 40% of total crop production. Grass leaves are typical monocot leaves - narrow with parallel venation, as in the corn plant above. As contrasted with netted venation, veins in leaves with parallel venation are all of about equal size, usually very numerous, and all parallel with each other. They are sparsely joined by inconspicuous cross-veinlets.

Like dicot leaves, the leaves of monocots show a diversity of form. In onions they are tubular, and in palms they are large and fanlike. The grasses, like corn, have a characteristic leaf type. The grass leaf is divided into two parts, sheath and blade. The blade is the typical thin, expanded portion. The sheath (red pin) is green, perhaps nearly as large as the blade, and completely sheaths the stem. In corn, it extends over at least one complete internode. The blue pin marks a node. Examine the region where the blade and sheath join and locate the small flap of delicate tissue that extends upward from the sheath. This is the ligule, which may serve to keep water and dirt from sifting down between stem and sheath.

actually not Crabgrass

(click on image for larger version)

Fig. 1. Monocot Leaf