Opposite leaves - Plants with two leaves at each node, one on each side of the stem, are said to have opposite leaves. The next pair of leaves on the next node are rotated about 45 degrees so that they are not directly over the previous pair. Plants with opposite leaves have even-leaf numbers only. These plants generally appear shorter than plants with alternate leaves at a similar leaf stage. Be sure to count each pair as two leaves.
Hemp nettle is a weed which has opposite leaves.
Whorled leaves - More complex plants like cleavers may have whorled leaves. These plants have three or more leaves at each node on the stem. The leaf number in each whorl may vary, so be sure to count each individual leaf unless label recommendation refers to the number of leaf whorls. In recent years, the number of herbicide-resistant weeds and the areas they infest in Manitoba have increased. Growers who have developed weed resistance on their farms will typically see a weed, which is normally controlled by a herbicide, escape uncontrolled after a number of years of use of the same product or product group.