On a recent walk in the woods, I spotted the leaf of a Cranefly Orchid (Tipularia discolor) peeking out from beneath a covering of fallen leaves, an oak leaf its top blanket.

Cranefly Orchids can be found in deciduous woodlands, primarily from New Jersey and southeastern Pennsylvania west to southern Illinois, south to southeastern Texas and northern Florida. It can even be found in pockets as far north as New York and southern Michigan. Cranefly Orchid becomes less common in the northern- and southern-most parts of its range.

They have an unusual lifestyle, similar to that of another orchid, Puttyroot (Aplectrum hyemale).  Like Puttyroot, a Cranefly Orchid typically produces only one oval-shaped leaf, deep green on the top with a purple underside.  The leaf emerges in fall, and withers before the flower cluster appears in mid to late summer.  Without competition for sunlight from the canopy of leaves that shades it during the growing season, Cranefly Orchid is able to photosynthesize during the winter, gathering the energy it needs for its summer bloom, usually in July or August.

Cranefly Orchids benefit from the covering of leaf mulch produced by the deciduous trees and shrubs with which it lives in the forest. This blanket of leaves protects and nourishes the Cranefly Orchid and other surrounding plants, including those from which the leaves fell.  The leaves hold moisture from winter rain or snow, slowly releasing it into the soil.  With the assistance of beneficial fungi and bacteria, the leaves decompose, replenishing the nutrients in the soil.  Cranefly Orchids also depend on the presence of special fungi in the soil for germination and to obtain essential nutrients for growth and survival.  Plants provide food in the form of carbohydrates to the fungi, and in return, the fungi work with other soil microbes to provide nutrients and water from the soil to the plants.

Cranefly Orchid’s stemmed flowers bloom along an unbranched stalk. The flowers don’t all bloom at once; they start blooming from the bottom of the stalk, working up to the top.  This gradual blossoming extends their chances for pollination over a longer period, usually about three weeks.  In bloom, Cranefly Orchid grows to a height of about 15-20 inches (38-50 cm).

Both the common name for this plant, Cranefly Orchid, and the genus, ‘Tipularia’ (which translates to daddy long-legs), refer to the shape of the individual flowers.  If you use your imagination, they resemble a long-legged insect.

Rather than dispensing its pollen as individual grains that may adhere to the body of the insects that visit its flowers, the pollen of Cranefly Orchids is packaged in a sac-like structure called a pollinium. This makes for an all or nothing method of pollen dispersal. Pollination of Cranefly Orchid flowers is accomplished primarily with the help of night-flying moths from the Noctuidae family. As the moth reaches with its tongue down to the tip of the long spur for nectar, the asymmetrical structure of the flower is such that one of the moth’s eyes may come in contact with and pick up the pollinium. The pollinium adheres to the moth’s eye until it is deposited on another flower, preferably with receptive female parts, or until it is brushed off.

Studies have shown Armyworm Moth (Mythimna unipuncta) as the flower visitor that is most likely to be a successful pollination partner for Cranefly Orchid. At least one reference mentions other specific members of the Noctuidae moth family as potential pollinators, including the Common Looper Moth (Autographa precationis).

Producing flowers and fruit have a big cost in energy for Cranefly Orchids. As a result, they don’t bloom every year.  Even the size of the leaf produced in winter may vary, depending on how much energy the plant has available.

I became acquainted with this particular orchid in August about 10 years ago, when I first saw the plant in bloom. While I have been able to spot a leaf most winters, I haven’t seen it bloom since.  Will this be the year it has enough energy to invest in reproduction?

Related Posts

An Orchid in Winter

Resources

Beadle, David; Leckie, Seabrooke. Peterson Field Guide to Moths of Northeastern North America. 2012.

Rhoads, Ann Fowler; Block, Timothy A. The Plants of Pennsylvania.  2007

Spira, Timothy A. Wildflowers & Plant Communities of the Southern Appalachian Mountains & Piedmont.  2011.

Stearn, William T. Stearn’s Dictionary of Plant Names for Gardeners.  1996.

USDA Forest Service Plant of the Week

USDA NRCS Plant Database

Go Orchids – North American Orchard Conservation Center

Studies on the Pollination Ecology of Tipularia discolor (Orchidaceae), By Dennis F. Whigham and Margaret McWethy, American Journal of Botany Vol. 67, No. 4 (Apr., 1980), pp. 550-555

Costs of Flower and Fruit Production in Tipularia Discolor (Orchidaceae), by Allison A. Snow, Dennis F. Whigham

In Defense of Plants

Butterflies and Moths of North America
http://www.butterfliesandmoths.org/species/Mythimna-unipuncta
http://www.butterfliesandmoths.org/species/Autographa-precationis