Chaffheads are Quirky

Carphephorus species

(Carphephorus means “has chaff”)

Asteraceae, the Daisy Family

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Autumn in Florida!   Well, ok, most of our fall color comes from poison ivy, but still there’s a subtle botanical transition.   The red maples are red, the bald cypress is yellow, and the fall wildflowers are feeling their oats, especially the Aster Family:  golden goldenrods, blue mistflowers, and purple chaffheads,  aka Carphephorus, the last-mentioned being the featured players today.   Every member of the genus Carphephorus has a curious feature.

Let’s start with Carphephorus pseudoliatris, a species from more-northern counties.   Its name means fake Liatris, but guess what, DNA evidence from botanist Gregory Schmidt and collaborators shows it to belong in Liatris. Why was it banished as a phony to begin with? It has chaff.  Chaffheads get their name from little scaly scales around the bases of the flowers within the flowerhead.  Seems that chaff alone is not a true ticket to Carphephorus membership.

Vanillaleaf, Carphephorus odoratissimus, makes our world smell nice, and its name is a hint to what it smells like:  a delicious essence of vanilla (which normally comes from an orchid), or more accurately, coumarin.  Coumarin is found in many plants, including freshly mown hay, tonka bean, and cinnamon, and is controversial in the kitchen because, as it adds fragrance and flavor, it is also adds liver damage.  in addition to coumarin, vanillaleaf has about 90 volatile ingredients.  In any case, the main commercial service from C. odoratissimus is to enhance cosmetics and to flavor tobacco.  OK in wacky  tabacky but a no-no in foods.

Vanillaleaf by John Bradford

Pineland chaffheads, Carphephorus carnosus, has two probably linked claims to fame: first, that its total natural distribution is in  central Florida, reaching its southern limit in Palm Beach County, and second, that it is the only species with a sunken rosette.  Its whorl of basal leaves is dented down into the ground subtly reminiscent of the tanks on some bromeliads. We must then ask, what is it about Central Florida that causes a plant to evolve rosettes that hunker down a little below ground level?    My guess:  fires that sweep quickly through pine woods.  Keep your head down, and the cavity would  hold some water, adding protection from fire and drought. 

Carphephorus carnosus by JB

The sunken rosette yesterday. Look how the middle sinks into a dark hole of mystery.

Our final species has an unusual basal feature too.  As its growing season begins it launches up to about 5 new shoots to its perennial root, which is no big “oh my,” but the odd feature is that only one survives.   In short, the plant conducts an experiment launching five potential new candidates  and yet chooses only one, much like the U.S. political primary system.  

Carphephorus corymbosus parachutes, by JB

C. corymbosus mongram by Linda Cooper

So how does the root system decide which of its candidates to put forward?   And how does it then suppress the others?   Go figure!   Possibly that the biggest new shoot hormones that somehow abort the smaller shoots.  

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