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Science & NatureWhat is That?What Is That … Pappus?

What Is That … Pappus?

WaddellsWhile snowshoeing across frigid expanses of glistening snow near our home, we notice the tops of dead plants protruding through the snow.  Some of these plants sport furry white coats where the flowers once were.  Was it a response to the recent stretch of below -20 degree Celsius temperatures?  Alas, we know this is not ‘fur’ to keep the plants warm; it is pappus.

We suspect that most people are familiar with the sight of pappus but may not know this specific term.   Most commonly recognized examples are the furry white seed heads of dandelions and the seed pods of milkweed when they split open to release their silky white contents.  Pappus is most often produced by these and other members of the aster family of flowering plants.  One of our field guides defines pappus as comprised of the hairs, bristles or scales at the top of the seeds.   Carolyn defines it as the fluffy white stuff.  The pappus and seeds are gradually distributed by the wind and animals over the course of the autumn, winter and spring and so pappus can be found most times of the year, including winter.  We have a number of pappus-producing plants around our cottage at White Lake and wanted to share a few with you.

The purple flowers of the bull thistle are a common sight along the roadside at our cottage.  This biennial, a member of the aster family, can grow to a height of 1.5 meters.  Plants produce one or a few terminal discoid flowers from June to September.  Each flower produces a cluster of small seeds attached to a pappus of white feathery hairs.  Birds, notably some finches, are known to feed on the seeds and use the pappus to line their nests.  This photograph, taken in late August, shows both a bloom and a flower that has gone to seed.

Another member of the aster family that is common around the cottage is goat’s-beard.   This biennial plant can grow to a height of one meter.  Its solitary light-yellow-coloured flowers can be seen along the roadside from June to September.  The plant produces small seeds attached to white, feathery pappus that resembles a parachute.  The seed head of goat’s-beard resembles the seed head of the dandelion but is much larger.  This image was taken in July and shows two plants, one in bloom and one that has gone to seed.

Several species of goldenrod are abundant along the roadsides near our cottage.  Their clusters of terminal bright yellow flowers are visible from August to October.  All of these species are perennial plants and are members of the aster family.   Different species can grow to heights ranging from one to two meters.   When the flowers go to seed they produce numerous white hairs attached to each small seed.  Pictured are one species in bloom and another that went to seed in September.

Another member of the aster family, horseweed, is commonly found along our cottage roadside.  Also called Canada fleabane, the annual plants can grow to 1.5 meters in height.  They produce terminal flower clusters from May to September but the small light green flowers are not conspicuous.  Plants are most noticeable when they have gone to seed because of the greyish-white hairs attached to their seeds. This photo was taken in August.  Horseweed contains a compound that irritates the nostrils of horses, hence the common name.

Not all pappus-producing plants belong to the aster family.  The cattail is a common perennial found in the marshes around White Lake.  These aquatic plants can grow to 2.7 meters in height.  Flowers are produced from June to July on spikes.  The male flowers are at the tip of the spike with the female flowers immediately below.  The greenish-yellow female flowers produce clusters of numerous small seeds attached to silky brown-beige fluff.  The flowers and the brownish club-shaped mass of seeds and fluff resemble the tail of a cat, hence the common name.  Cattail rhizomes, leaves, seeds, and pappus are an important source of food and building material for some birds and aquatic rodents.  This picture from last June shows spikes of both new flowers and pappus from last year’s growth.

These are just a few of the pappus-producing wildflowers we find at our cottage.  Pappus fulfills several functions, including the distribution of seeds; the use by birds and mammals to provide a soft lining in their nests; and, historically, as a warm filling for bedding and clothes of some Aboriginal people.  Alas, it does not help keep the plants themselves warm through the winter.

We relied on two sources for this article. Timothy Dickinson, Deborah Metsger, Jenny Bull and Richard Dickinson’s The ROM Field Guide to Wildflowers of Ontario; and Steven G. Newmaster, Allan G. Harris and Linda Kershaw’s Wetland Plants of Ontario.

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