Know Your Natives – Yellow Passionflower

Yellow passionflower (Passiflora lutea) of the Passifloraceae (Passionflower) Family is found in the US from Texas to Kansas to Illinois and eastward to the coast.  In Arkansas, it is found throughout the state.  Yellow passionflower is more delicate in appearance and less aggressive than purple passionflower.  The species grows in moist bottomland and upland forests to medium-dry, rocky upland woodlands and thickets, doing well in bright shade or partial sun.

Yellow passionflower is a small, unbranched herbaceous perennial vine with trailing, climbing or sprawling stems up to fourteen feet long (but often encountered a few to five or six feet long).  New vines can grow upright for a couple of feet on their own before gravity wins out, unless support can be found on other vegetation.  The number of vining stems increases from year-to-year near its original location, generally not spreading widely underground like its larger, showier cousin.  One or more tendrils and/or flowers arise from each leaf axil.  Tendrils typically exhibit a spring-like appearance.  As vines mature, the lower leaves drop off.

Alternate leaves, dark green on top and light green below, consist of three smoothly rounded, shallowly cut lobes with entire (no teeth) margins.  Each lobe is centered by a primary vein.  Lateral veins, which are slightly arcuate, arise at about a 50o angle off the central veins.  The three primary veins terminate just slightly past the leaf margin.  Leaves, from 2½” to 6” wide and 2″ to 4½” long, may be strongly mottled with irregular lighter green areas, but tend to become more uniform in color with maturity.  Leaves are generally spaced from one to two inches apart along the stems, with spacing decreasing in brighter light.  Multi-stemmed plants in bright light can have a dense layer of leaves floating above the stems.

Photo 1

Photo 1:  Leaf and tendril of yellow passionflower.  With maturity, leaf patterns (if any) may fade.

Flowering of yellow passionflower occurs in May to July.  Flower buds are elongated and squared-off and indented at the stem end.  Flowers are a light greenish yellow (“lutea” is Latin for yellow). The structure of the perianth, corona and reproductive portions of flowers of yellow passionflower are very similar to those of purple passionflower, however, parts are significantly smaller, with total flower diameter only about one inch.  Whereas sepals and petals of purple passionflower are of about equal width, petals of yellow passionflower are narrower than the sepals.

Photo 2

Photo 2:  Yellow passionflower bud and flower.  Note broad sepals and narrow petals.

Photo 3

Photo 3:  Flower structure as seen from the side.  Note spring-like tendril in foreground.

Flowers are followed by small, round and smooth green fruits (berries) on long, thin stalks such that the fruits dangle from the stems.  Seeds, up to 10 per fruit, are each surrounded by a membrane filled with liquid.  Upon ripening, fruits become dark bluish purple with a whitish haze.  Ripe fruit is soft and releases a staining purple liquid when squeezed, the membranes having disintegrated.  Dark brown seeds, about 0.15” long and half as wide, have points at both ends and a textured surface.

Photo 4

Photo 4:  Mature fruit on five or more intertwined stems of yellow passionflower supported on eastern redcedar.  Dried flower parts persist on the fruits.

Photo 5

Photo 5:  Seed of purple and yellow passionflower for comparison.  Note characteristic texture of each.

Yellow passionflower is an interesting plant in a garden or natural area.  The leaves, tendrils, flowers and fruit all add interest.  Its rambling but sparse growth habit allows it to drape over other plants without any particular effect to other plants.  This plant, attractive to bees and small wasps, is the only pollen source for the solitary ground-nesting Passionflower Bee (Anthemurgus passiflorae).  Along with purple passionflower, yellow passionflower is also a larval host plant for the Gulf fritillary butterfly.  Wildlife eat the fruit and disperse the seed.

Photo 6

Photo 6:  Gulf Fritillary caterpillar on purple passionflower (Passiflora incarnata) leaf.

Photo 7

Photo 7:  Adult Gulf Fritillary butterfly on blue sage (Salvia azurea).

Article and photographs by ANPS member Sid Vogelpohl

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Know Your Natives – Purple Passionflower

Purple passionflower or maypop(s) (Passiflora incarnata) of the Passifloraceae (Passionflower) family is found in the US from Kansas to Illinois to Pennsylvania, south to Texas and Florida.  In Arkansas, it occurs statewide.  Purple passionflower, a herbaceous (non-woody) perennial vine, grows well in acidic or slightly alkaline soils that are sandy, loamy or clayey in nature and where sunlight is abundant.  Preferred sites are disturbed areas, stream banks, overgrown pastures and roadsides.  (See footnote regarding common names.)

Early Spring growth of an established plant.  Tendrils growing from leaf axils.

Early Spring growth of an established purple passionflower plant.  Note tendrils growing from leaf axils.

Purple passionflower has long trailing, non-twining, mostly unbranched stems that grow rapidly and can reach 20 feet in length.  Growth habit is a combination of climbing and sprawling.  Tendrils and/or flowers at leaf axils grow at the same time as when the leaves first form.  Tendrils, four or more inches long, grow in random directions away from the leaf while flowers grow skyward.  Plant are generally glabrous (without hairs) to occasionally finely hairy, especially on young stems; immature ovaries are densely, velvety hairy.

A fresh flower with typical coloration.  Flowers may be more white or more purple.  Ovary immediately below three styles. 

A fresh flower with typical coloration.  Flowers may be more white or more purple.  Note the ovary immediately below the three styles but above the five stamens.

Widely spaced, three-lobed alternate leaves, on petioles that are short in comparison to blades, are dark green above and light green below.  Leaves have short, closely spaced rounded teeth with broadly rounded, deeply cut lobes that are acutely pointed.  Major veins, at the center of each lobe, extend from petiole to tips of lobes.  Veins of the two side lobes are about 50o off the central vein.  Leaf blades, about four inches long and five inches wide, may lie flat or be slightly folded along the three major veins.  A pair of raised, oval glands are found on the petiole just below the leaf blade.

On this healthy specimen, day-to-day succession from bud to fruit and raised glands on petiole (just below leaf) can be seen.

On this healthy specimen, day-to-day succession from bud to flower to developing fruit as well as raised glands on the petioles (just below leaf blade) can be seen.

Flower buds, elongated and squeezable, consist of five somewhat leafy sepals with each having a central sharp ridge which terminates with a prominent soft “spine”.  These spines encircle an open area at the top of the bud.  Showy flowers, occurring singly, are two and a half inches wide.  The perianth (portion of flower below reproductive portion) consists of five sepals, five petals and a corona made up of long, round filaments that are crinkly near the ends.  Perianth and reproductive portions of a fresh flower are reflexed downward; however, the perianth reflexes upward after fertilization.

A maturing fruit which will become yellow, then dry.  Sepals still attached.

A maturing fruit of purple passionflower, which will become yellow and dry at maturity. Note dried sepals still attached.

The color of the petals, patterned in white and purple, and the color of the inside of the sepals generally mirrors that of the corona.  Five stamens with large anthers and a pistil of three styles and stigmas are elevated above the corona with the ovary in between (superior position).  The pollen bearing side of the anthers hangs down in the space between the corona and styles so that pollination is performed by large bees rummaging about for nectar.

Photo 5

Variegated  Fritillary caterpillar on purple passionflower leaf.

Ovaries of fertilized flowers develop quickly into two-inch, egg-shaped to rounded fleshy fruits on long petioles.  The green fruit contains 100± seeds with each seed individually surrounded by a membrane containing a viscous, edible (and tasty) material.  With maturity, the fruit becomes yellowish and dries to a crispy outside skin.  Dark brown seeds, about 0.25” long and half as wide, have smooth edges and sides that are randomly, but densely pock-marked (as result of ridges encircling lower space).

Gulf Fritillary on dittany aka wild oregano (Cunila origanoides)

Gulf Fritillary adult nectaring on dittany, aka wild oregano (Cunila origanoides)

Purple passionflower can be a great addition to a native garden or retained in a natural setting.  However, its clambering growth habit and its habit of popping up in inconvenient places may be drawbacks to a more formal setting (stems can be easily pulled off roots, though, for control). In especially droughty conditions, the plant may shrivel and go dormant early, but returns the following year.  Purple passionflower is an important larval host plant for the Gulf Fritillary and Variegated Fritillary.

Note:  Another native Arkansas passionflower, yellow passionflower (Passiflora lutea) will be featured in a later posting…

Footnote

“Passionflower,” named by 16th century Spanish missionaries who related flower parts to Christ’s crucifixion or the “Passion of Christ.”   Namely, 1) Five sepals and five petals represent the disciples, excluding Peter and Judas, 2) Five stamens represent five wounds, 3) Three styles represent three nails, and 4) Corona represents crown of thorns.

“Maypop” may derive from the plant’s growth habit of “popping up” in unexpected places in spring or that the fruit “may pop” when stepped on. 

 Article and photos by ANPS member Sid Vogelpohl

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Field of Prairie Blazing Stars

White Liatris

Recently I found this rare white form of prairie blazing star (Liatris pycnostachya) in Dallas County. Photo by ANPS member Mike Weatherford

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