Identifying  Characteristics:

Arisaema triphyllum,commonly known as Jack-in-the-Pulpit is aperennial herb which grows in the moist under story in woodland habitats.  It has one or two trifoliate leaves and flowers in the spring (April-June).  Plants can remain vegetative or may produce a single male female inflorescence or clustered arrangement  of flowers. The inflorescence consists of a central spadex which holds the flowers surrounded by a tube with a hood or spathe on top.  The spathe can range in color from green to purple.  The flowers are located at the base of the spadex.  The spathe or hood acts as a “kettle trap” of pollinating insects. Male plants have a small hole at the bottom of the spathe. Insects enter through the top and are drawn to the light (and pollen) at the bottom where they exit. Females do not have an escape route so once an insect enters through the top, there is a very small chance that it will find its way out (Ewy Unpublished).

Male pollinator enters inflorescence, falls to the bottom, collects pollen and escapes through hole. Female pollinator enters the inflorescence in the same fashion, but is not able to escape. (Vogel and Martens, 2000) (Ewy, Unpublished)

 

Map from the Plants Database
http://plants.usda.gov/

Distribution

A. triphyllum has a fairly extensive range in the United States as shown on the map.

 

Natural History

Life cycle

The Photos above are of the growth season of a female plant.  The above ground portion of a male plant would simple fade away, or completely senesce, after the pollen had been distributed.  Underground each plant has a corm which survives throughout multiple growing seasons.  It is through this corm that A. triphyllum is able to survive multiple growing seasons.  Energy is stored in the corm for the following growing season. The red berries produce 1-7 seeds each.

 

Habitat Requirements:

A. triphyllum grows best in wet woodland areas.  It survives well in the shady undergrowth.  Moister is essential and is considered a wetland plant.

 

Nutritional Requirements:

No specific nutritional requirements are known

 

Reproduction:

 

Hermaphroditism:    Sex Choice Variation….

Jack-in-the-pulpits are able to change sex between growing seasons. This is thought to be dependent on plant size. If a particular plant was a female in one growing season and was able to produce many seeds, it is likely that that plant was not able to store much energy for the following growing season in its underground corm as most of its resources would have been devoted to reproduction. The following growing season, that same plant would have better reproductive success by being a male or a non-flowering plant.  With less energy reserves, the plant would be able to devote much of its energy to growth and production of pollen which takes less energy the production of seeds.

As the graph on the right shows, a plant has a better rate of reproductive success (RS) when larger plants are female, and the smaller plants are male (Policansky, 1981). The method of distinguishing a male plant from a female is by observing the interior of the inflorescence:  If there are green berries, as the plant in the photo above, the plant is a female. A male plant has pollen instead of berries, and the interior is a whiter color. A.triphyllum can reproduce sexually, through transfer of pollen from a male plant to a female, or it can reproduce asexually through the corm. Additional shoots are sent out from the corm at the beginning of the growing season and produce new plants. It is common to see number of smaller plants around a larger parent plant.  A disease called Uromyces ari-triphylli which is a rust that inflicts A. triphyllum is transmitted through asexual reproduction, but not through sexual reproduction (Rust, 1980)

Figure Policansky, 1981.  “Sex choice and the size advantage model in jack-in-the-pulpit Arisaema triphyllum).” National Academy of Science, 1981

 

Interactions:

The Pollinator of Jack-in-the-Pulpit is thought to be the Fungus gnat, however this has been highly debated.   However more research must be done for more conclusive results.

 

Predation

As with most other plants, A. triphyllum is vulnerable to predation by animals such as the caterpillar feasting on maturing berries as shown in the photo.  Personal observation showed that the impact these caterpillars have on Jack-in-the-Pulpits is very devastating. 

 

Human Interest:

Jack-in-the-Pulpits are fascinating to study in multiple aspects and there is still much to learn.  While currently no known feature of this plant has a direct impact on human life, more studies are yet to be conducted.  The environmental value of A. triphyllum is not something easily assessed.  

 

Ecology/Conservation Issues:

A. triphyllum is not endangered or rare.  As it is hardy enough to withstand cold winters through its underground corm.   As with many other plants and animal species, we do not full understand the impact or value they have until they are no longer around.

 

Acknowledgements and References:

 

Thanks to Dr. Jarosz, Jessica Cook and Erin Mason.

 

Chadde, Steve.  2002.  A Great Lakes Wetland Flora-A complete, Illustrated Guide to the Aquatic and Wetland Plants of the Upper Midwest.  PocketFlora Press, Calumet, MI.  648 p.

Ewy, Nick.  Unpublished. Insect pollinators of Jack-in-the-Pulpit.

Ghiselin, Michael.  (1969).  The Evolution of Hermaphroditism Among Animals.  The Quarterly Review of Biology.  44; 189-208.

Kirkby, Kyle. Unpublished.  Frequency of Seed Set of Arisaema triphyllum: Effects of Spider Presence and Disease on Seed Production.

Policansky, David.  1981.  Sex choice and the size advantage model in Jack-in-the-pulpit (Arisaema triphyllum).  Proc. Natl Acad. Sci USA 78(2) 1306-1308.

Rust, Richard.  1980.  Pollen movement and reproduction in Arisaema triphyllum.  Bulletin of the Torrey Botanica Club.  107(4) 539-542.

Vogel S, Martens J.  2000.  A survey of the function of the lethal kettle traps of Arisaema (Araceae), with records of pollinating fungus gnats from Nepal.  Botanical Journal of the Linnean Society, 133:  61-100, Figure 2 p.86

Plants Database. 11/20/2003 <http://plants.usda.gov/>

 

Unless otherwise noted all pictures are by Tammie Reynolds