Sex life of Arisaema triphyllum (Jack-in-the-pulpit)

Arisaema triphyllum (Jack-in-the-pulpit) is a common plant that grows in forests throughout the eastern half of the United States. Jack-in-the-pulpit is the most common of its common names but you might also see this species called Indian turnip, brown dragon, or bog onion. Although common, this extraordinary plant species has some amazing characteristics and ecology. Jack-in-the-pulpit can change its sex (sexual hermaphrodotism or dichogamy) and this is not a one time event. This species can go back and forth between being male and female.

 

Fig. 1 Arisaema triphyllum (Jack-in-the-pulpit).

Jack-in-the-pulpit is in the largely tropical Araceae or aroid family. Like many members of the aroid family, the flowers are located on a spadix (the "Jack") which is surrounded by a spathe (Figure 1). Relatives like Symplocarpus foetidus (Skunk cabbage) have "perfect" flowers, that is they have both male and female reproductive parts, while others have male and female flowers separated on the same spadix. In Jack-in-the-pulpit, however, the plants are dioecious with separate male and female flowering plants (Figure 3). Note: You can find some plants with both male and female flowers but this is more common in its close relative Arisaema dracontium (Green dragon).

 

Fig. 3 Spadix with male flowers, not much more than four anthers.

 

Pollination is mostly accomplished by attracting and tricking fungus gnats in the Superfamily Sciaroidea, mostly Mycetophilidae family. Fungus gnats are tiny little flies, usually less than 2.5 mm long. The adults have a life expectancy of less than two weeks. During this time, they don't even eat. They just need to reproduce. Fungus gnats are attracted to Jack-in-the-pulpit by the slight fungal smell coming from the spadix. Fungus gnats normally seek out fungi to lay their eggs. In this way their larvae will have a suitable food source. But this is no fungus. Doh! They have been duped!

 

Fig. 4. Male spathe with exit hole.

To further complicate the scheme, male plants of Jack-in-the-pulpit have a hole at the bottom of the spathe (Figure 4) but the female plants do not. In this way, they allow fungus gnats to pass all the way through the male inflorescence before finally exiting out the bottom covered in pollen. The flies do this over and over until they finally reach a female plant. Since there is no hole at the bottom of the spathe they are effectively stuck to perish in the bottom of the spathe but the female flowers of the Jack-in-the-pulpit have been pollinated. Fortunately each female fungus gnat can lay hundreds of eggs and a high percentage of them do find their intended target (a fungus).

Interactions between insects and plants are so interesting and complicated.

 

 

IN SEARCH OF THE FRENCH-GRASS FLOWER MOTH

(SCHINIA NR-JAGUARINA)

Schinia nr-jaguarina (French-grass flower moth or Sainfoin flower moth). The scientific name used here is just a placeholder used on Bug Guide (https://bugguide.net/node/view/1638554) since this species has not been officially named at this point. Oh yeah, and I totally made up those common names.

Anyway, here I am, an Illinois botanist in search of a rare moth caterpillar. Who would have thunk it? I can’t hardly believe it either. As far as I remember, I first became aware of this rare moth and its striking caterpillar about five or six years ago after seeing a blogpost by Jim McCormac (https://jimmccormac.blogspot.com/2012/07/interesting-moth-new-to-science.html). I have searched for it a few times in the past, but this year I decided to get serious. Other Schinia flower moths are reliably found on specific host plants and as a botanist I know that I can find this caterpillar’s host plant, Orbexilum onobrychis (French-grass or Sainfoin). Huh, so maybe it does make sense for a botanist to look for a flower moth. French-grass is not a common plant but it is distributed widely across 13 eastern U.S. states and Illinois is at the center of its distribution (See distribution map from BONAP).

Orbexilum onobrychis (French-grass or Sainfoin)

 As an Illinois botanist, I know of several central Illinois populations for French-grass. Also, a few friends have kindly alerted me to additional locations (Thanks, Matt, Matt, and Jared!). One of these new to me sites is just a short 20-minute drive from my home. So close that I could not pass up the opportunity, so this past Friday I took a much-needed day off work and went to check it out. This site is a remnant prairie that was both protected and neglected because of the adjacent railroad. In the past, several local prairie heroes from Champaign and Vermilion counties have looked after high-quality sections of this prairie corridor. Now the railroad is gone and replaced by a bike path. This site, although degraded, is once again receiving some love, this time by the local Champaign County Forest Preserve District (CCFPD) staff.

Distribution map from BONAP.

I was able to park close to the bike path prairie corridor, at a local farm access. With my camera in hand, I started walking down the bike trail, with my expectations low. After all, this caterpillar which feeds on a reasonably common plant remained unknown for hundreds of years. Surely it won’t be here. Not today. At first I was just passing the time sweating and taking photos of grass inflorescences and weedy plants that came in along the new path, but it didn’t take long to find a nice sized population of French-grass. The nice thing about French-grass is that it is a large showy plant and it forms extensive colonies. It is not necessarily an easy plant to find since it is absent from most of what seems to be suitable habitat but, if you know of a location, it is an incredibly easy plant to notice and not one that you are likely to just walk by.

Warty legumes of Orbexilum onobrychis.

So here it, a nice population of French-grass running for tens of feet parallel to this narrow corridor between U.S. 150 and the bike path. The plants are in flower so, even though I do not see any caterpillars right off the bat, I start taking photos of French-grass flowers. They are beautiful! Racemes full of small blue-purple legume flowers. Then I notice the fruit has started to develop, a somewhat pointy and odd-shaped warty legume. I guess I’ll take some photos of those too. I got a little distracted and started chasing some grasshoppers and other insects around the plants, some I’m able to catch up to and photograph and others just provide me with some exercise. Then, right in front of me, I see my first caterpillar of Schinia nr-jaguarina, the French-grass flower moth. It’s maybe about two centimeters long, yellow with dark black spots in lines down its body. A striking little caterpillar for sure. After a little more searching, I saw a few dozen caterpillars, most very small at this time.

             

At this point, it seems this amazing little caterpillar has been found in Ohio, Indiana, Kentucky, Illinois, and Missouri and I believe this is at least the fourth record in Illinois. Hopefully, I'll be able to find a few more locations while the caterpillars are still out and about.

Success came easy this time but it was still sweet and I was overjoyed to have finally encountered this little mystery organism. Next year, I want to get to the site earlier to try to photograph some mature moths. Onward to the next search!              

Cypripedium candidum Muhlenberg ex Willdenow (White lady’s-slipper orchid), a brief summary of the species status in Illinois.

Paul B. Marcum

Cypripedium candidum (White lady's-slipper orchid) in hand for scale. The smallest lady's slipper in Illinois and one of the smallest in North America.

Lady’s-slipper orchids are a joy to behold! There are approximately 45 species of lady’s-slipper orchids (genus Cypripedium) in the world. They are found nearly throughout the Northern Hemisphere, but especially in temperate Eurasia and North America. Of the approximately 15 taxa in North America, the White Lady’s-slipper orchid (Cypripedium candidum) is one of the very smallest (Sheviak 2002). The whole plant is often only 15-25 cm tall and the tiny lip or namesake slipper part of the flower is only 17 to 27 mm long. For comparison, the slippers of some of its eastern North American relatives (Large yellow lady’s-slipper orchid, Cypripedium parviflorum var. pubescens and Showy lady’s-slipper orchid, Cypripedium reginae) are usually more than twice as long. White lady’s-slipper orchids can be very difficult to find when they are not in flower and may lay hidden under overhanging vegetation. Fortunately, they usually grow in small clusters of many flowering stems, sometimes upward of 50. Look for White lady’s slipper orchids in alkaline wetlands, usually fens, wet-mesic prairies, or around the edges of sedge meadows. Be prepared for wet knees as your search may require crawling to find and inspect the flowers up close. Flowering usually occurs in mid- to late-May with extreme flowering records as early as late April and as late as mid-June.
 
Although NatureServe designates White lady’s-slipper orchids as globally secure (G4), this species is currently rare to uncommon throughout its range. It has been recorded in 18 eastern U.S. states, mostly in the northeast and northcentral parts of the country, with isolated records from Alabama. White lady’s-slipper orchid is Presumed Extinct (SX) in Pennsylvania, Critically Imperiled (S1) in South Dakota, Nebraska, Missouri, Kentucky, Alabama, Virginia, New York, New Jersey, and Maryland, Imperiled (S2) in North Dakota, Wisconsin, Illinois, Michigan, and Ohio, and Vulnerable (S3) in Minnesota, Iowa, and Indiana (NatureServe 2020). Unfortunately, this once widespread and at least occasionally encountered species has suffered a drastic decline in population numbers. The primary reasons are habitat loss, invasive species, woody encroachment, and outright poaching. NOTE: NEVER REMOVE ANY NATIVE PLANTS FROM REMNANT SITES UNLESS THE POPULATION IS THREATENED WITH CERTAIN DESTRUCTION. Naturally occurring remnant plant communities are invaluable and represent years of crucial interaction and relationships among its inhabitants (plants, animals, fungi) and the environment. For many species, these conditions cannot be easily created. Cultivation of lady’s slipper orchids require very specific conditions and significant knowledge and most efforts to cultivate lady’s-slipper orchids in a home garden or even in a restoration area will result in death of the plants. Please, don’t do that. Also, only purchase native plants, especially rare species, from reputable dealers that are growing and actively propagating the species.

A clump of White lady's-slipper orchids, approximately 20 cm tall.

In Illinois, White lady’s-slipper orchid has a similar story. It was once widespread and at least occasionally encountered. Records stored in herbaria throughout Illinois and across the country document this species from 25 counties across the north half of the state (Herkert and Ebinger, eds. 2002). Unfortunately, many of these populations were lost very early as Illinois was settled. Widespread conversion of land for agriculture has all but extirpated the species from downstate Illinois. Mohlenbrock (1970) stated “this species, along with the Yellow lady’s-slipper and the Showy lady’s-slipper, were not infrequent in the state before 1900. Indiscriminate collecting, however, has made all of these species rare in Illinois to the point of extinction.” Additional population losses accumulated over time and, by 1981 when the inaugural Illinois rare plant list was published, this species was listed as endangered within the state. Fortunately, this is when the story started to change for this tiny endangered plant. Since 1981, many populations have been discovered and protected in numerous state nature preserves, county forest preserves, and on private land. People care and started to protect and care for our remnant natural communities. Natural community restoration and habitat management started to become a widespread and common practice and the results were being seen on the ground. By 1999, things were starting to improve for White lady’s-slipper orchids and the species was downlisted from endangered to threatened. With White lady’s slipper orchid specifically, habitat management in the form of prescribed burning, invasive species management, and removal of encroaching woody species has had a tremendous positive impact on populations. Staff and volunteers with the Chicago Botanic Garden’s Plants of Concern Program (POC) have monitored this rare species for several years and to date have monitored more than 50 populations. Increased fire on the landscape, coupled with other management, has resulted in population increases at many sites and in 2015 White lady’s-slipper orchids were officially delisted in Illinois.

Of course, the story doesn’t end here. Continued vigilance and care are needed. Natural remnants must always be protected and cared for. In Illinois, most downstate populations have been lost but a few remain intact. Let’s expand on the work that has occurred in northeast Illinois and do what we can to save this species throughout Illinois and throughout its range.

All photos from northeast Illinois, wet-mesic prairie over dolomite, May 24, 2020.

Literature Cited and References:

Herkert, J.R. and J.E. Ebinger, editors. 2002. Endangered and Threatened Species of Illinois: Status and Distribution, Volume 1 – Plants. Illinois Endangered Species Protection Board, Springfield, Illinois. 161 pp.

Mohlenbrock, R.H. 1970. The Illustrated Flora of Illinois, Flowering Plants, Lilies to Orchids. Southern Illinois University Press, Carbondale and Edwardsville, Illinois. 288 pp.

NatureServe. 2020. NatureServe Explorer [web application]. NatureServe, Arlington, Virginia. Available at https://explorer.natureserve.org/. (Accessed: June 5, 2020).

Plants of Concern. 2020. Plants of Concern, a project of the Chicago Botanic Garden. Plants of Concern, Chicago, Illinois. Available at https://plantsofconcern.org/our-policies. (Accessed June 5, 2020).

Sheviak, C.J. 2002. In: Flora of North America Editorial Committee, eds. 1993+. Flora of North America North of Mexico. 19+vols. New York and Oxford. Vol. 26.