The definition of line is the visual path the eye follows as it moves through the design. This can be presented in the design many ways. To find the line in a design, begin by determining if the line is actual or implied. An actual line is where the line is physically represented by product in the design. An implied line is where your brain plays "connect the dots" with different product in the floral composition.
Your next step is to determine if the line is static or dynamic. A line is static if it is either vertical or horizontal. Any other line, such as a diagonal, zigzag or curvilinear, is considered dynamic.
The last step in evaluating the line is to determine the style of the line such as connective, radial, Hogarth curve, etc. Adding a line element to your design should always be purposeful with the intent on guiding the viewer's eye through the design. You can impact how the viewer looks at your design and how long they linger on it.
You can download a 24"x36" PDF poster, a worksheet and a printable of this visual on the TSFA Member's Only Info Hub.