Definition - What does Spike mean?
In botany, a spike refers to a type of inflorescence (flower arrangement) that bears taller-than-average flowers, most usually on an axis that is unbranched. Similar to a raceme, the spike bears flowers that are directly attached to the plant, without any stalks whatsoever. Spikelets are smaller spikes comprised of several florets that are enclosed by sterile bracts.
MaximumYield explains Spike
Spikes are one type of inflorescence, which are clusters of flowers that are normally found in an intricate arrangement of stems and branches.
Unlike raceme inflorescences, spike flowers do not have any pedicels. Instead, they open directly in an ascending direction that moves from the base to the very top of the plant.
One of the better-known intricately shaped spikes occurs on Spiranthes. Belonging to the orchid family, this plant has often been compared to hair tresses because of its interwoven spikes.
Other examples include wheat and rice.