At Risk

Natural History, May, 1999 by Janet Marinelli

The beautiful swamp pink is one of seven hundred species of flowering plants that the U.S. Department of Fish and Wildlife lists as endangered or threatened.

In 1910 Stewardson Brown wrote in Bartonia, the publication "of the Philadelphia Botanical Club: Few of out early spring flowers are more attractive or universally sought after by those who know it than the swamp pink.... Many of the more accessible localities of our region are sure of visits each spring from enthusiasts, who feel amply repaid by a few heads of its fragrant flowers, even if the getting entailed some scratches, with wet feet thrown in." Brown went on to note that those who have never seen the plant in the wild "do their hunting along the curbs of Market Street, for it is almost certain to be found there among the variety of wild flowers brought from New Jersey."

I got my first glimpse of swamp pink (Helonias bullata) in the wild last year, when I joined New Jersey State biologist Larry Torok for a day of slogging through the swamps of southern New Jersey in search of this threatened plant. Collecting swamp pink is no longer legal, but protection came only after decades of removal from the wild had taken their toll. In addition, years of draining, filling, timbering, and clearing have decimated the wetland haunts of this native wildflower. To reach suitable habitat, we first had to make our way through the procession of carbon-copy suburbs, strip malls, and roadway mazes collectively known as the urban fringe. As we pulled up to a housing development full of shrubs pruned into lollipops, pom-poms, and corkscrews--the starting point for our hike--Larry took another look at my sleeveless blouse, white pants, and high-tops, and grabbed an extra pair of rubber boots from the back of his truck.

The temperature soared into the mid-nineties as we tramped by a line of juniper pom-poms, past a concrete headwall designed to slow down the subdivision's storm-water runoff, and into a shady--though only slightly covered maple swamp. Within minutes, I was drenched in sweat, covered by catbrier scratches, and splattered with mud. Thanks to the boots, however, it didn't much matter that I'd already sunk shin-deep in the muck.

The plant we were seeking once grew in wooded wetlands, shaded by the tangled canopies of trees and shrubs. It ranged from New York's Staten Island to the Georgia border. It is currently hanging on by a thread in the coastal plains of Delaware and Maryland and in a few scattered populations in the southern Appalachians. Southern New Jersey supports more than half of all known swamp pink populations, most of which are on privately owned land in the Delaware River valley.

The swamp pink grows in infertile, saturated, acidic soils. During the cold winter months, its low-growing clump of straplike leaves, often hidden under leaf litter, turns reddish brown and hugs the ground. The flower head, a small oval about an inch and a half long, is scarcely visible tucked inside the leaf clump. In late winter--as sunshine pours through the bare tree branches of New Jersey's red maple swamps and warms the soil--a stout hollow stem, called a scape, begins to rise from the center of the clump, eventually reaching eighteen inches or more in height. At the top of the scape, the flower head quickly lengthens into an oblong cluster, or inflorescence, of forty to sixty tiny flowers with a hyacinth-like fragrance. Each flower possesses six bright pink tepals (the term used when there is no distinction between petals and sepals). Protruding from the tepals are six stamens topped by vivid blue, pollen-bearing anthers shaped like little coffee beans. By early spring, flowering swamp pink is the jewel of the wetland, the dazzling pink-and-blue flower clusters on their blue-green scapes punctuating the brilliant greens of young swamp grasses and sedges unfolding their leaves on the damp forest floor.

Once the flowers are past their prime, the inflorescence now pink suffused with green--continues to lengthen and bears papery three-lobed fruits resembling tiny inverted hearts. Each fruit contains about 50 long slender seeds; altogether, the average swamp pink inflorescence produces a lot of seeds--nearly 2,500 by one calculation.

The problem with this pretty picture of fertility is that even in relatively healthy Helonias populations, a swamp pink in flower is a rare sight: no more than 6 percent of the plants bloom in a given year. And when a swamp pink does bloom, its flowers tend to pollinate themselves. The many small hermaphroditic flowers are huddled together, facilitating pollen transfer, and each one has tall pollen-shedding male parts that tower over the shorter female organ, the carpel, with its pollen-receptive stigma. Such self-pollination may be convenient but, unlike cross-pollination of flowers from different plants, does not promote a healthy reshuffling of genes with each generation.

What's more, swamp pink tends to reproduce asexually, producing new clumps--clones of the parent plant--that arise from the roots. Asexual reproduction has advantages for a population that is already well adapted to its environment: in effect, it's Mother Nature's version of the adage "If it ain't broke, don't fix it." The relative lack of genetic diversity that accompanies self-fertilization and asexual reproduction, however, especially in rare and narrowly distributed species such as swamp pink, can become a liability when habitat conditions change. Recently, swamp pink has been found to have unexpectedly low levels of genetic variation, further clouding its prospects for long-term survival.