The Lady Slipper newsletter, and now blog, of the Kentucky Native Plant Society has been published since the Society’s founding in 1986. We occasionally feature an article from a past issue. In this article from 2011, Tara Littlefield discusses the rare Kentucky shrub, sweet fern (Comptonia peregrina) . This article ran in Vol. 26, No. 1. If you would like to see these and other past issues, visit the Lady Slipper Archives, where all issues from Vol. 1, February 1986 to Vol. 40, 2025, can be found.

Sweet fern—A rare Kentucky shrub with an interesting history

By Tara Littlefield, Office of Kentucky Nature Preserves

The wax myrtle or bayberry family (Myricaceae) is known for its odor. These plants have resinous dots on their leaves, making their leaves aromatic. Plants in this family have a wide distribution, including Africa, Asia, Europe, North America and South America, missing only from Australasia. Myricaceae members are mostly shrubs to small trees and often grow in xeric or swampy acidic soils. More familiar members of the wax myrtle family include many in the Genus Myrica (sweet gale, wax myrtle), some of which are used as ornamentals and are economically important. In addition, the wax coating on the fruit of several species of Myrica, has been used traditionally to make candles.

So what does this interesting family have in common with Kentucky’s flora? We are lucky to have just one species in the wax myrtle family, Sweet fern (Comptonia peregrina). In addition, it is also a monotypic genus restricted to eastern North America. This means that the genus Comptonia has only one species (C. peregrina) worldwide, and just happens to be found here in KY! Of course the common name sweet fern is misleading. This woody shrub is certainly not a fern. However, the leaves have a similar shape to pinnules of a fern frond (leaf). But having sweet in the common name is no mistake. If you crush the leaves throughout the growing season, a lovely smell is emitted as the essential oils volatilize into the air.

Sweet fern is a clonal shrub that grows up to one meter high and spreads through rhizomes. The leaves are alternate and simple, linear and coarsely irregularly toothed, dark green above and a bit paler below. It is monoecious (meaning male and female flowers on different plants). The female flowers are not showy— short rounded catkins [dense cluster of apetalous flowers, usually associated with oaks, birches and willows] with reddish bracts. The male flowers are elongated yellow-green catkins clustered at the branch tips, the pollen being adapted to wind dispersal. The fruit is a round, bur-like cluster of ovoid nutlets that turn brown when mature in late summer. The bark is reddish and highly lenticeled (small corky pores or narrow lines on the bark that allow for gas exchange).

While very common in the northern part of its range (northeastern United States and Canada), sweet fern is state listed endangered in Kentucky, along with being state listed as rare in Ohio, Tennessee, South Carolina, West Virginia, Georgia, and North Carolina. The populations of sweet fern in the southern part of its range are isolated and disjunct from the common habitats up north. There seems to be a close association of these remnant populations with the Appalachian Mountains, which suggests that the populations in the southern ranges remained in protected “refugia” during periods of great plant migrations, such as during glaciations.

Sweet fern is typically found in openings in coniferous forests with well drained dry, acidic sandy or gravely soils with periodic disturbances. In the north, it can be found in pine-oak barrens or jack pine and spruce forests that are maintained by fire, creating openings and decreasing competition. It has also been noted to colonize road banks and even highly disturbed soils such as mined areas. Contrary to these open coniferous habitats with periodic fire, the remnant populations of sweet fern in Kentucky and Tennessee are found on sandstone cobble bars, which are maintained by annual floods. Despite being found on habitats that are maintained by different disturbance regimes, these two communities share a few things in common—they are both dry, acidic, sandy and nutrient poor. Disturbances are a natural occurring impact in these communities that removes shrubs and saplings, thus decreasing competition so that sweet fern can thrive.

Sweet fern has adapted to these specialized habitats. It is a fires adapted species; it will resprout after a fire and increase its clonal sprouts through underground rhizomes. It is also a xerophyte, a plant adapted to dry conditions. And since it is adapted to living in nutrient poor, acidic soils, it has evolved with the bacteria Frankia that fixes nitrogen, somewhat like the more famous nitrogen fixing legumes who have partnered with the bacteria Rhizobium. Did you know that there are over 160 species of nonleguminous plants that fix nitrogen? It is also the host of the sweet fern blister rust (Cronartium comptoniae) which reduces the growth of pines, particularly Jack pine. What interesting relationships this shrub has with bacteria and fungi! In addition, sweet fern is the food plant to larvae of many species of Lepidoptera (moths and butterflies). These include the Io moth (Automeris io), and several Coleophora case-bearers (some of which are found exclusively on sweet fern).

But perhaps the most fascinating facts about the rare shrub sweet fern is what it can tell us about the evolution of plants, the history of the earth, and the paleovegetational past of Kentucky. Geologically speaking, sweet fern is an old plant. In Kentucky, it was most likely more common some 20,000 years ago during the last glaciation, as Kentucky used to look like Canada. Analysis of pollen in sediment cores taken from natural ponds in Kentucky confirms this, spruce and jack pine was common in the uplands in the bluegrass. Sometimes it is difficult to think of plants migrating north and south in order to adapt to a changing climate. But what is even more mind blowing is that the genus Comptonia is perhaps millions of years old. Numerous fossils of dozens of extinct species of Comptonia have been found all across the Northern hemisphere, and the earliest of the fossils have been dated back to the Cretaceous period (the age of the Dinosaurs) over 65 million years ago. The first flowering plants (angiosperms) evolved only 135 million years ago, so Comptonia is one of the oldest living plants in the world—a true living fossil!

So when April comes around, and all of the spring wildflowers are emerging, think of sweet fern tucked deep into the gorges of Big South Fork and Rockcastle, its catkins releasing pollen in the wind, using the nitrogen fixed from its bacterial friends, withstanding the massive floods of two of Kentucky’s last wild rivers. And if you use your imagination, you may be able to see dinosaurs and tree ferns in the distance.

Berry, Edward W. 1906. Living and Fossil Species of Comptonia. The American Naturalist. Vol. 40, No. 475, pp. 485-524.

Darlington, Emlen. 1948. Notes on some North American Lepidoptera reared on Sweet Fern (Compontia asplenifolia Linnaeus) with Description of new species. Transactions of the American Entomological Society (1890-). Vol. 74, No. ¾, pp. 173-185.

Liag, X., Wilde, V., Ferguon, D., Kvacek, Z, Ablaev, A., Wang, Y., and Li, C. 2010. Comptonia naumannii

(Myricaceae) from the early Miocene of Weichang, China, and the paleobiogeographical implication of the genus. Review of Paleobotany and Palynology. Vol. 163, p. 52-63.

Medley, Max and Eugene Wofford. 1980. Thuja occidentalis L. and other noteworthy collections from the Big South Fork of the Cumberland River in McCreary County, Kentucky. Castanea. Vol. 45, No. 3, pp. 213-215.

Natureserve Explorer, 2010.

Wilkins, Gary, Delcourt, Paul, Delcourt, Hazel, Harrison, Frederick, and Turner, Manson. 1991. Paleoecology of central Kentucky since the last glacial maximum. Quaternary Research. Vol. 36, Issue 2.

Virginia Tech Woody Database https://dendro.cnre.vt.edu/dendrology/syllabus/factsheet.cfm?ID=869

Zomlefer, W. 1994. Guide to Flowering Plant Families. University of NC Press, Chapel Hill.

The Lady Slipper newsletter, and now blog, of the Kentucky Native Plant Society has been published since the Society’s founding in 1986. We occasionally feature an article from a past issue. In this article from 2007, Maggie Whitson discusses the botany of the American persimmon (Diospyros virginiana). This article ran in Vol. 22, No. 1. If you would like to see these and other past issues, visit the Lady Slipper Archives, where all issues from Vol. 1, February 1986 to Vol. 40, 2025, can be found.

The Pleasing Persimmon

by Maggie Whitson

With large orange fruit dangling from bare branches like Halloween ornaments, the American persimmon (Diospyros virginiana L.) puts on a striking late fall display along our fields and roadsides. The numerous sweet fruits were notable enough to find their way into the genus name, which means “fruit (-pyros) of the gods (dios).”

Persimmons are common in Kentucky and occur throughout the state. The species is found as far south as Florida and ranges up the Gulf Coast to Connecticut. It laps from the Southeast on to the Midwest and peters out around eastern Texas. Like many widespread plants, persimmons have a variety of common names, ranging from picturesque to puzzling. To list a few: dateplum, seeded-plum, winter-plum, simmon, lotus-tree, Jove’s fruit, and possum-wood.

Though the typical persimmon has a trunk ranging from about 6″ to 24″ in diameter, given optimum growing conditions and plenty of time, they can get much larger. Kentucky’s champion persimmon is located in Ballard County, and is 113.5 inches around, or about 36″ wide. The U.S. champion tree is in Portsmouth, Ohio, and is a whopping 142″ in circumference and 82 feet high.

Due to their deeply ridged bark which forms block-like plates, persimmons are easily recognized even in the leafless condition. The twigs are also distinctive, if only internally, as they often have diaphragmed piths. That is, when a twig is cut at an angle, its exposed center displays ladder-like divisions. Persimmon leaves are relatively nondescript, being simple, entire, alternate, and ovate. However, the undersides are often marked with fine black speckles (probably tannins).

While persimmons look similar throughout their range, they actually vary in chromosome number. A 60 chromosome race is common in the Southeast, while a 90 chromosome race is found throughout most of the Midwest. It is thought that there may also be a 30 chromosome race in southern Florida. These races do not readily hybridize with one another.

Persimmons bloom in May and June and are typically dioecious, with separate male and female trees. However, individuals capable of self-pollination are occasionally found, and sometimes a tree will produce flowers of both sexes one year and flowers of only one sex the next. The small, bell-shaped white flowers are eagerly pollinated by bees, and their industrious buzzing may be more obvious than the flowers, which are nearly invisible high up in the leafy branches. Persimmons belong to the Ebenaceae, or ebony family, which has only three genera. Diospyros is by far the largest, and with about 450 species single-handedly saves the family from obscurity. Most persimmon relatives are woody, and this pantropical group is well-represented on the Malay peninsula, in Africa and Madagascar, and in Central and South America. Interestingly, while people eat the fruit of many species in this genus, the few temperate species are the most famous fruit producers.

As a member of the ebony family, it is perhaps unsurprising that D. virginiana’s other claim to fame is its incredibly hard heartwood. In the Old World tropics, D. ebenum and D. reticulata are the best producers of ebony, though most species in the genus also produce hard, dark wood. Here in the U.S., the wood of D. virginiana was best known for its use in golf clubs, but was also used to produce other items such as tool handles, mallets, shuttles, and the lasts on which shoes were made and repaired. These days, synthetic materials are more commonly used for many of these products.

The Southwestern U.S. hosts our only other native Diospyros, the chapote, or D. texana. It has fuzzy, blackish fruit which are edible as well as being used as a source of natural dye. These shrubs or small trees range from Texas into northern Mexico, and like D. virginiana, the hard wood has been used locally for products requiring durability. The bark is smooth and attractively peeling, giving these plants potential value as ornamentals

In the temperate zones, there are three species of persimmons commonly eaten. The Asian persimmon, D. kaki, is widely cultivated in China and Japan and is now appearing more frequently in American supermarkets.

The date plum, D. lotus, is a similar species from Eurasia and has long been eaten in Europe. Finally, our own D. virginiana was particularly enjoyed by both the native Americans and early settlers. Persimmons are mentioned in the writings of early explorers such as Don Fernando de Soto and Captain John Smith. By 1626, many English gardens sported American persimmon trees. However, since fruits were most often simply harvested from wild trees, there are few improved varieties available today. Most of our native persimmons are cultivated for wood, as ornamentals, or as grafting stock for Asian persimmons.

Ripening throughout the Fall, the 1″-2″ fruits approach tangerine orange (or occasionally blackish-brown) upon maturity. They vary widely in shape, ranging from nearly round, to somewhat flattened, to long ovals. (One can see similar variation in cultivated Asian persimmons.) Shape aside, they’re all full of seeds. A single persimmon berry can contain up to eight, flat, woody seeds. At almost 1/2″ long by 1/3″ wide, the seeds themselves are quite large. During the shortages of the Civil War, Southerners supposedly drilled holes in them and used them as buttons. The large seeds don’t deter true fans from eating the ripe berries, which are a favorite of wildlife, hunters, children, livestock, and occasionally dogs

Though there is some interest in improving fruiting varieties of our native persimmon, only limited progress has been made. While ripe persimmons have a rich and intensely sweet flavor, even slightly unripe fruit are astringent with tannins, and will leave your mouth with an unpleasant, bitter, puckery feel — not unlike eating a very green banana. Though non-astringent Asian varieties have been bred, this breakthrough has not yet been achieved in the American persimmon. Thus, the fruit can only be harvested when dead ripe. In fact, the best persimmons are usually those that have just fallen from the tree. Since ripe persimmons are almost pudding-like in texture, they often split when they fall and certainly do not ship well. Persimmons are also generally flecked with dark tannin deposits, which doesn’t effect the flavor, but does make them look imperfect. Add all this to the relatively small fruit and large seeds, and American persimmons so far remain in the realm of home-garden curiosities, rather than commercial fruit production.

None-the-less, both the Indiana Nut Growers Association (INGA) and the North American Fruit Explorers have several webpages dedicated to American persimmons and the challenges involved in selecting quality fruiting cultivars. Jim Claypool of Illinois may be the most famous amateur persimmon breeder, and he amassed a collection of over 2,000 trees. When his health failed, INGA inherited much of his collection, which they continue to use for breeding work. The Missouri Agricultural Experiment Station also keeps a persimmon germplasm collection and has an orchard planted with 21 cultivars selected from Claypool’s trees.

Several mail-order nurseries carry American persimmon cultivars, including ‘Meader’, ‘Early Golden’, ‘Garretson’, ‘John Rick’, and ‘Prok’. More unusual are the hybrid varieties made by crossing American and Asian persimmons. The most common are ‘Nikita’s Gift’ and ‘Russian Beauty’, both of which were bred in the Ukraine. They have slightly larger fruit than the typical American persimmon while being much cold hardier than the Asian species. One Green World Nursery in Oregon and Raintree Nursery in Washington state both carry American cultivars, Asian cultivars, and the hybrids.

Not only can American persimmons be eaten fresh or dried, but they have been cooked in a variety of ways. Settlers commonly made persimmon puddings, bread, and preserves. In addition to eating the fruit, they fermented it and made persimmon beer, brandy, and wine. Today, there is still a limited market for frozen persimmon pulp, which can be used in anything from ice cream to cookies to cakes. Persimmons generally work well in recipes designed for pumpkin, and introducing 50% persimmon pulp into a pumpkin pie recipe is a simple and tasty way to enter the field of persimmon cookery.

While American persimmons may never surpass bananas, apples, and oranges at the supermarket, they are attractive, easily grown trees with a long and interesting history. A ripe persimmon makes a wonderful late fall treat, and is a ecologically friendly way to enjoy the woodland resources of our state. So next time you’re out enjoying the fall wildflowers, don’t miss the opportunity to admire the persimmons, as well.

SELECTED REFERENCES:

Anonymous. 2006. The story of James Claypool. Indiana Nut Growers Association website: www.nutgrowers.org/persimmon.htm Accessed 10/06.

American Forests. 2007. The National Register of Big Trees website: www.americanforests.org/resources/ bigtrees/ Accessed 03/07.

Baldwin, J. T. Jr. and R. Culp. 1941. Polyploidy in Diospyros Virginiana L. American Journal of Botany 28(10): 942-944.

Harrar E. S. and J. G. Harrar. 1962. Guide to southern trees. Dover Publications, Inc., New York. Heywood, V. H., editor. 1993. Flowering Plants of the World. Updated edition. Oxford University Press, New York.

Kentucky Division of Forestry. 2007. The Kentucky Big Tree Program website: http://www.forestry.ky.gov/programs/kybigtree/ Accessed 03/07.

Lehman, J. W. 2006. The American persimmon. North American Fruit Explorers website: www.nafex.org/ persimmon.htm. Accessed 10/06.

Medsger, O. P. 1973. Edible wild plants. 3rd printing. Macmillan Publishing Company, Inc., New York.

Spongberg, S. A. 1979. Notes on persimmons, kakis, date plums, and chapotes. Arnoldia 39 (5): 290-310.

Thomas, A. L. 2006. Persimmon research orchard and germplasm collection. Missouri Agricultural Experiment Station website: www.aes.missouri.edu/swcenter/ fieldday/2005/ page78.stm. Accessed 10/06.

Vines, R. A. 1977. Trees of East Texas. University of Texas Press, Austin.

The Lady Slipper newsletter, and now blog, of the Kentucky Native Plant Society has been published since the Society’s founding in 1986. We occasionally feature an article from a past issue. In this article from 2011, KNPS Board Member David Taylor, discusses one of Kentucky’s most widespread milkweed, common milkweed (Asclepias syriaca). This article ran in Vol. 26, No. 3. If you would like to see these and other past issues, visit the Lady Slipper Archives, where all issues from Vol. 1, February 1986 to Vol. 39, 2024, can be found.

Kentucky’s Common Milkweed (Asclepias syriaca L.)

By David Taylor, US Forest Service

Common milkweed is a perennial forb that spreads by means of rhizomes and seed. It is one of about 115 species that occur in the Americas. Most species are tropical or arid land species. Plants may occur as a few individuals, but once established, form small to large colonies. Individual plants range from 1 to 2 m (~ 3 to 6 ft) tall. Leaves are elliptic to ovate to oblong and somewhat thick. Mature leaves are 15-20 cm (6-8 in) long and 5 to 9 cm (~ 2 to 3.6 in) wide, with a prominent midvein. The underside of the leaf is frequently finely pubescent. The stem is stout, usually simple, and green to black (see below) in color. When broken, the leaves, as well as stem and fruit, exude milky latex. Flowers are purplish to rosy pink to mostly white or even greenish and about 2 cm (0.75 in) long and 1 cm (0.4 in) wide. They occur in semi-spherical umbels (umbrella-like clusters) in the upper leaf axils. Flowers are somewhat complex in their structure, with structures not found in the average flower (see Cut Flower Exports of Africa – Asclepias). The flowers are strongly and sweetly scented. The fruits (pods), known as follicles, are formed from the union of multiple flowers. They are green, covered in soft spiky projections and are finely pubescent. When the seeds are mature, the follicle splits exposing the seeds. Each seed is equipped with a coma, a soft group of hairs. As the newly exposed seeds dry, the hairs of the coma expand allowing the seed to catch a ride on the wind. When broken, the leaves, as well as stem and fruit, exude milky latex.

The Lady Slipper newsletter, and now blog, of the Kentucky Native Plant Society has been published since the Society’s founding in 1986. We occasionally feature an article from a past issue. In this article from 2004, Alan Weakley, looks at the taxonomic changes in the 1990s that moved American asters out of the Eurasian genus Aster into several American genera . This article ran in Vol. 19, No. 3. If you would like to see these and other past issues, visit the Lady Slipper Archives, where all issues from Vol. 1, February 1986 to Vol. 39, 2024, can be found.

The Curious Case of the Disappearing Asters . . .

by Alan Weakley

Reprinted with permission of the author from the North Carolina Botanical Garden Newsletter 32(2). March-April 2004.

Would an aster by any other name look as showy?

One dark and stormy night in 1994 I was awakened from a deep sleep by a loud thump. Creeping carefully down the stairs, I discovered to my astonishment that a large bouquet of Aster on the dining table had disappeared! In its place was a cornucopia of composites, including Symphyotrichum, lonactis, Eurybia, Sericocarpus, Doellingeria, Ampelaster, and Oclemena! Once again, a plant taxonomist had struck in dark of night, taken a simple two- syllable genus with the same English common name, and replaced it with a handful of four- and five-syllable Latin tongue-twisters. Whatever can we do about such things?

The classification of living things is based on the principle that each taxonomic unit (for instance the Composite or Aster Family, the genus Aster, or a species) groups together things that are most closely related to one another, and that the group should not also contain things which are disparate, unrelated, or more closely related to another group.

The concept of the genus Aster has had a long history of controversy and confusion. Asa Gray, the most influential nineteenth-century North American botanist, struggled with Aster at all levels, from its circumscription (what to include in it), to the taxonomy of the component species. Late in his life, he wrote:

“I am half dead with Aster. I got on very fairly until I got to the thick of the genus, around what I call the Dumosi and Salicifolia. Here I work and work, but make no headway at all. I can’t tell what are species and [sic] how to define any of them …. I was never so boggled …If you hear of my breaking down utterly, and being sent to an asylum, you may lay it to Aster, which is a slow and fatal poison.”

The Lady Slipper newsletter, and now blog, of the Kentucky Native Plant Society has been published since the Society’s founding in 1986. We occasionally feature an article from a past issue. In this article from 2010, the late Tom Barnes, wildflower photographer and former president of Kentucky, takes an in-depth look at the gentians (Gentianaceae family) . This article ran in Vol. 25, No. 4. If you would like to see these and other past issues, visit the Lady Slipper Archives, where all issues from Vol. 1, February 1986 to Vol. 39, 2024, can be found.

Gentians: All Fall Color is Not Red, Yellow and Orange

Thomas G. Barnes, Ph.D.
Extension Wildlife Specialist, Department of Forestry, University of Kentucky

Fall is the time of the year when the leaf peepers begin their road trips across the Commonwealth in search of reds, yellows, oranges, and other colors in the tree canopy. For wildflower enthusiasts it is a time of the year when they think of other activities since the goldenrods and asters are done flowering and the drabness of winter is quickly approaching. For those who do love searching for unique wildflowers, like so many do for our native orchids, this is the time of the year to search for fall flowering members of the gentian family, those that typically have beautiful blue flowers. When you think of the rarity of the native orchids found in Kentucky, approximately 38% are listed as rare, special concern, threatened or endangered. Of the fall gentians, 68% fall in those same categories. So if looking for rare plants is your venue, then the fall gentians are an excellent group to focus on. I hope to share with you some information about gentians in general and then which species can be found in Kentucky.

Jeff Nelson, KNPS President

Over the last several years, we have seen an explosion of interest in the growing of native milkweed plants (Asclepias genus), largely driven by the plight of the iconic monarch butterfly (Danaus plexippus). As most of us are aware, monarch caterpillars only host on milkweeds. Without milkweed leaves to feed on, monarch caterpillars cannot not survive.

Asclepias is a genus of herbaceous, perennial, flowering plants known as milkweeds, named for their latex, a milky substance containing cardiac glycosides termed cardenolides, exuded where cells are damaged. Most species are toxic to humans and many other species, primarily due to the presence of cardenolides.

The Lady Slipper newsletter, and now blog, of the Kentucky Native Plant Society has been published since the Society’s founding in 1986. We occasionally feature an article from a past issue. In this article from 2005, Robert Paratley, Curator, University of Kentucky Herbarium, takes an in-depth look at the dogbane family, Apocynaceae. This article ran in Vol. 20, No. 1. If you would like to see these and other past issues, visit the Lady Slipper Archives, where all issues from Vol. 1, February 1986 to Vol. 39, 2024, can be found.

The world of the dogbane family Apocynaceae

Robert Paratley
Curator, University of Kentucky Herbarium

Indian-hemp or dogbane, Apocynum cannabinum, is a tall, branching perennial found in most parts of Kentucky. It is very common in old fields, roadsides and other disturbed habitats, but is not particularly conspicuous in flower, with small greenish-white flowers whose petals are fused into a small urns hape. Indian-hemp is more conspicuous in fruit, where the two parts of the pistil separate at maturity and elongate into narrow, dark, long-pointed follicles (pods). These are filled with numerous light, tufted seeds adapted to catch the wind, making it an effective seed disperser. Break the plant and the sap is milky white. Another species, the spreading dogbane (Apocynum androsaemifolium), is similar but smaller than Indian-hemp and is widespread in northern U.S. It is listed as rare in Kentucky. Both species are on any serious list of poisonous plants. Numerous cases of livestock poisoning have been recorded, although apparently no human cases are known. (Turner and Szczawinski, 1991).

Both are members of the Apocynaceae, a large, mostly tropical family of mostly woody members. This article will highlight the features of this complex, diverse family that barely gets a toehold in the temperate zone. The Latin genus name Apocynum was coined by Linnaeus. He combined two Greek roots, apo meaning “away” or “off”, and cyn meaning “dog” – a dog repellent. The common name echoes this idea. (Perhaps dogs found the scent of the European dogbane Apocynum venetum unpleasant and kept away from it.) Apocynum became the namesake genus for the family Apocynaceae, whose name is credited to the French botanist Antoine-Laurent de Jussieu in the early 1800s. Until recently, the concept of the family remained fairly consistent, including about 200 genera and 2,000 species (Cronquist, 1981). Recent research has expanded the concept of the family to include the milkweeds, which have traditionally been taught as a distinct but closely related family. Following older fashion, I will not discuss milkweeds here.