Know Your Natives – Fire Pink

Fire pink (Silene virginica) of the Pink or Carnation (Caryophyllaceae) family is an herbaceous woodland perennial with bright red flowers.  In the U.S., fire pink is found from Florida to New York and westward to northeast Texas, Kansas and Minnesota.  In Arkansas, it occurs across the highlands of the northwestern half of the state.  Its habitat includes partially sunny sites of open woods with various dry to mesic soils where ground vegetation is sparse.

This species occurs as single plants or small colonies of scattered plants.  The base of the plant comprises a woody branched caudex that rests directly on the soil surface, along with a branched tap root, and white fibrous roots growing directly from the caudex.  The caudex of a mature plant has multiple growth points.

Appearance of the basal leaves varies depending on the plant’s age and the season.  New plants have egg-shaped leaves with a constricted base (obovate).  Mature plants have rosettes of basal leaves that are spoon-shaped (spatulate) with narrow elongated bases.  Fresh basal leaves have a dark green upper surface and a lighter green lower surface.  Margins are entire (without lobes or teeth), but may be crinkled.  Although leaf surfaces are glabrous (hairless), hairs occur along the margins (ciliated margins), but only from midleaf (short hairs) to leaf base (long hairs).  Basal leaves that survive over winter assume a reddish color.

Fire Pink - Silene virginicaPhoto 1:  These multiple leaf rosettes are growing from a single caudex.  Flowering stems are poised to grow as can be seem on the left side.  Photo in late February.

Flowering stems grow from centers of leaf rosettes in late winter to early spring.  These main stems, which may grow to a foot or more long, have dense short pubescence.  Initially, stems grow outward, nearly parallel to the ground.  As they mature, stems arch upward so that the plant in full bloom exhibits an open structure with long, slender, wide-spreading to erect stems.  Main stems bear two to six pairs of opposite, clasping leaves (the cauline leaves) with leaves of lowermost pairs being similar to basal leaves, but with wider bases.  Lower leaf pairs are spaced up to about 4 inches apart.  Upper leaf pairs, which become closer together and much smaller toward top of stems, are somewhat ovate with gently acuminate tips.   Lowermost cauline leaves may be five inches long while upper leaves may be only ¼ inch long.  Stems, round in cross-section (terete) and hollow (fistulose), may have a mature length of about 1½ feet.   Stems tend to be reddish on their sunny side and green on shaded side.

Fire pink’s stems have a growth pattern which could be called “pattern-of-three”, that is, leaf pairs at about mid-stem typically subtend a combination of secondary stems and flowers that total “three”.  At about mid-stem, leaf pairs subtend two secondary stems and one flower located between the two stems (referred to herein as “axillary flower”).  When this “pattern-of-three” includes two secondary stems, one of the stems is dominant and it may produce an additional stem.  All stems terminate with a group of three flowers.  On a main stem or secondary stem, the first flower to reach anthesis is the lowermost axillary flower, followed by terminal flowers of secondary stems.  Up to about 30 flowers may occur on one main stem.

Fire Pink - Silene virginicaPhoto 2:  A flowering stem with widely spaced pairs of leaves on its lower portion.  First flowers to open are axillary flowers between two secondary stems, as shown.  Note additional stems just appearing.

Flowers, occurring on separate pedicels, have calyxes composed of five fused sepals that are reddish to purplish on their sunny side while flowers are in bloom, but changing to medium green as flowers fade.  Individual flowers, which may remain showy for a week or more, are up to 1 inch long (calyx included) with a flat-faced corolla that has a width up to 1½ inches.  The corolla comprises five vibrant red petals that are evenly spaced in star-fashion.  Petals, as seen from corolla face, are elongate, each with a characteristic deep terminal notch* and often with short side wings angled toward the tip.  Petals have a sharp flexure where they transition from the corolla face to a tight floral tube formed by the overlapping of narrow petal bases.  Most of the floral tube is within the inch-long calyx tube, but about a fourth of its length is outside.  At the petals’ flexure points, they have two short red upward-extending flanges, so that five petals, as a unit, produce a small corona that encircles the floral tube.  The outside of the petals and exterior of the floral tube are a duller shade of red.  Flowers have ten light red stamens that are adnate to the short stalk of the elongate, yellow-green, cylindrical ovary hidden deep in the calyx.  Stubby, elongate, two-lobed anthers, balanced lengthwise at the tips of filaments, are at first light yellow but become grayish as pollen is released.  Three light red slender styles, arising from the apex of the ovary, have a sloped stigmatic surface.  The calyx tube, with five pointed teeth, is marked with 10 darker longitudinal ridges.  Within the confines of the calyx, bases of petals, stamens and pistils are white.

Stamens and pistils become exserted in sequence: First, the five stamens adnate to the petal bases; second, the five stamens attached in between the petal bases; and third, all three styles.  By the time the second set of stamens becomes exserted, stamens in the first set have lost their anthers and filaments have become back-flared and wilted.  Similarly, by the time the styles become exserted, stamens of the second set have also declined. This sequence of anther and style/stigma development lessens chances for self-pollination.

Fire Pink - Silene virginicaPhoto 3:  Even with a dozen main stems, the inflorescence is very open.

Fire Pink - Silene virginicaPhoto 4:  The corolla and corona are the same vibrant red.  As shown, all ten stamens have emptied their anthers of pollen and twisted backwards as stigmas become receptive to receiving pollen from a different flower.  Note the enlarged calyx behind the corolla.

Fire Pink - Silene virginicaPhoto 5:  In the flower shown with petals, two sets of five anthers are exserted while styles have not yet appeared.  The two flowers without petals show styles emerging with stamens in decline (lower center) and styles fully exerted with receptive stigmas, while stamens have wilted (upper left – note enlarging ovary).  A ridged calyx (center) is also shown.

Upper portions of flowering stems have short, glandular hairs that cause the upper stem, upper cauline leaves and caudex exterior to feel sticky (viscid).  The greatest degree of stickiness occurs nearest the flowers.  Small flying insects are often caught on the sticky surfaces and ants cannot reach the nectar.

Upon completion of bloom, calyxes become swollen, point downward and dry to a light tan.  When dry, calyx teeth roll well back so that the upper portion (now hanging down) of the calyx has a gaping hole.  The placenta of the fruit within the calyx disintegrates and the seeds readily fall out.  The small round, tan to brown seeds, with a tight C-shape, are covered with minute crowded knobs.  With flowering completed, stems gradually disintegrate, with basal leaves remaining through the summer into winter.

Fire Pink - Silene virginicaPhoto 6:  As calyxes dry, teeth roll back and seeds easily drop out.

For a garden or natural area with partial sunlight and good drainage, fire pink is an excellent year-round, well-behaved, low-maintenance choice that puts on a spectacular show of striking spring color.  Flowers are a favorite of hummingbirds, which are a principal pollinator.  Should past-bloom stems be untidy as they decline, they can be easily removed.

Eight additional species of the genus are known to occur in Arkansas of which the only one with red flowers is royal catchfly (Silene regia).  Royal catchfly is a taller clump-forming, heavily pubescent plant with more closely spaced, numerous cauline leaf pairs and un-notched petals.   Starry campion (Silene stellata), a white flowering species of the genus, has been previously addressed in this series of articles.

*The word “pink” relates to the cutting of cloth with pinking shears to prevent threads in woven cloth from unravelling.  The ends of fire pink’s petals appear to be “pinked”.

Article and photographs by ANPS member Sid Vogelpohl

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