This section is from the "The Herb Hunters Guide" book, by A. F. Sievers. Also available from Amazon: Herb Hunters Guide.

Figure 77.Maypop (Passiflora incarnata)
Passionflower, passion vine
This species of maypop grows in dry 60;1 or thickets from Virginia to Missouri and south to Florida and Texas.
This plant is a smooth vine with finely hairy stems climbing to a height of 10 to 30 feet. Its smooth or somewhat hairy leaves, 3 to 5 inches broad, consist of three oval or egg-shaped lobes with finely toothed margins. The flowers, which appear from May to July, are solitary and are characterized by a lavender and purple or pink and purple fringe 1 1/2 to 2 inches broad. The plant produces smooth, yellow, many-seeded, edible fruit almost 2 inches long, called maypops.
The herb.
 
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