It’s an odd-ball sort of bush.
It’s a native species – nothing odd about that – and it was originally restricted entirely to the coast, from North Carolina all the way to Mississippi. Now, though, it is common well inland within these states, and beyond, and appears to be continuing its spread.
For whatever reasons, this bush is easily able to colonize disturbed sites away from its original habitats, and can now be found along highway margins, ditches, powerline rights of way, and in old fields.
Perhaps one of the reasons that it has dramatically spread into inland sites is that it is so good at getting its seeds scattered here and there. Its seeds, of course, are tiny, each sequestered within a dry little fruit, much like the grain of a dandelion, aster or goldenrod, all of which are distant relatives to our mystery plant.
Each tiny little fruit that forms is the result of pollinations and fertilization of a female flower within a head, and each has a little parachute of fluffy hairs, very useful for dispersal.
You may have figured out, from these hints, that this bushy species is a member of the sunflower family, Asteraceae, a really interesting group of about 20,000 species, some of which have appeared in this column before.
The thing is, this bushy species occurs as either “male” or “female” plants, whenever it does occur. That is, some plants produce heads that feature only pistillate flowers (the “female” plants), and other individuals will produce heads that bear only pollen-producing flowers (the “male” ones).
There are examples of this situation in other plant groups, such as the maples, in which individual plants will either produce fruits and seeds, or they’ll produce pollen. Hollies do this, too.
Botanists, as you know, like terms, and the term we use for a plant species whose individuals are EITHER pistillate (that is, fruit/seed producing) OR staminate (that is, pollen-producing) is “dioecious.” It’s a useful term.
Now, it turns out that very few members of the sunflower family, at least here in the Southeast, are dioecious. Instead, most of the species in the family bear heads which contain flowers with both “female” and “male” parts. Another odd feature of our puzzling plant.
Finally, the very fact that our mystery plant is a shrub at all is something of an oddity. Most of the members of the sunflower family are not woody, but rather herbaceous.
It is true that in a wide variety of tropical habitats and desert settings, the sunflower family is represented by plenty of easily recognized shrubs or even trees. But here in the Southeast, not so many woody examples.
Now’s the time to be on the lookout for this species. It’s the female individuals that get all the attention. They are the ones that produce those grand, billowing branches of snowy fluff that you see while driving down the interstate. The male plants? Not so showy.
John Nelson is the curator of the A.C. Moore Herbarium in the Department of Biological Sciences at USC. As a public service, the herbarium offers free plant identifications. For more information, visit www.herbarium.org or call (803) 777-8196.