Final answer:
Orchard grass does not necessarily produce an inflorescence in every stem due to its growth patterns and the behavior of its apical meristem, which typically transforms into a flowering meristem only in certain conditions.
Step-by-step explanation:
Plants such as orchard grass do not always produce an inflorescence on every stem. Grasses only exhibit primary growth, starting from embryonic regions at the tips of roots and shoots. These regions include branch shoots and branch roots but do not undergo secondary growth, which would increase the width and woodiness of the plant. The apical meristem of grasses such as orchard grass remains close to the ground, and the stem is formed by the sheaths of leaves. Inflorescence only occurs when the shoot apical meristem, located at the base, transforms into a flowering meristem. This means not every stem in plants like orchard grass will necessarily bear flowers.
Orchard grass also produces tillers and branches in the form of stolons if they are above-ground, or rhizomes if they are below-ground, as seen in Fig. 8. These mechanisms can serve as a means of reproduction and provide mobility for the plant. In some cases, branches may not be easily recognized as in traditional plants, making the structure and inflorescence of grass plants, including orchard grass, unique.