How many plants among China Rose, Ocimum, Sunflower, Mustard, Alstonia, Guava, Calotropis and Nerium (Oleander) have opposite phyllotaxy?
Arrangement of leaves on the stem branches is called as phyllotaxy. There are 3 types of phyllotaxy present. These are opposite, whorled and spiral or alternate. In alternate type, leaf arises at each node in an alternate manner. Examples include china rose, sunflower, grass, mustard. In opposite type, pair of leaves arise at each node and are opposite to each other. Examples include Calotropis, Ocimum, guava. In whorled type, more than two leaves arise at a node and form a whorl. For example Alstonia, hydrilla, Nerium (Oleander). Thus, the correct answer is 'Three.'