Passion flower is a flowering and fruiting vine, known botanically by the genus name Passiflora, and also commonly as passion fruit. According to the USDA, there are more than 50 official species of the plant, with numerous cultivars within the species groups. Passion flower has a vining and climbing growth habit, using tendrils, and has evergreen leaves when grown in temperate and warm climes.
Look for the placement of the green leaves on the vines. Passion flower leaves are not paired on the vine but will be alternate. When a leaf appears on one side of the vine it will not have a leaf directly opposite on the other side.
Inspect the shape of the leaf. Passion Flower leaves will be deeply loped, with finger-like projections in groups of either three or five, depending on the species or cultivar. The lobes are generally oblong or pointedly oval and can range from three to eight inches in length along their central axis.
Observe and feel the edge of the leaves. Passion flower leaves will be finely serrated. While not sharp per se, the teeth can be seen and felt.
Check for differentiation in the surface texture between the top and bottom of the leaf. Passion flower leaves will be an even dark to mid-tone green and shiny on the top, with a dull surface in green or green with another color on the bottom.