Scrub Hickory and its Inner Phylloxerans

03 Mar

Carya floridana



Small Scrub Hickory.  All photos today by John Bradford.

Today John and I botanized  a local coastal hammock remnant, Maggy’s Hammock (aka Rocky Point Hammock)  near Stuart, Florida,  species galore in a square mile.   As tempting as it is to start listing, we better pick one species and stick to it.    The alpha trees are Florida hickories, some with trunks, oh say, a yard in diameter.   Florida hickory is well named, being restricted to Florida, living in high dry  habitats.

They are in full bloom today, although their wind-pollinated flowers are not showy.  The males dangle clustered in spikes called catkins.  The females stand solo.


Flowering twig.  Male flowers in catkins.  One green female flower at the twig tip.

Hidden within, the trees have a secret, phylloxeran galls*.


To explain the galls it is necessary to refer to another wonder of Florida nature:    Koreshans.    Phylloxerans  have much in common with Koreshsnas, just on a smaller scale:  they both lived on the inside of their globes.

The Koreshans were a utopian community  a couple generations ago at Estero, Florida, near Ft. Myers.  Their village persists  as a state park.  There’s a ton to tell about them, but to stay on-topic, the important thing is that they lived  inside the globe.   Koreshans knew the rest of humanity had the world-wrongside-out.

:This button may help you see where they lived:


Koreshan Unity button. 19–. Color photoprint. State Archives of Florida, Florida Memory. Accessed 3 Mar. 2017.

Today’s phylloxerans are the micro-Koreshans of Maggy’s Hammock.  They live on the inside of their little globose gall the diameter of a grape.    Slice it open…there’s a utopian world within.  Hundreds of tiny Koreshan phylloxerans.


We live inside

OK, cut the crazy crap, what’s a phylloxeran?   They’re kin to aphids, with many species infesting many plants.   They get along famously with grapes and hickories, entailing economic consequences for both.    The most important cultivated hickories are pecans, bothered by phylloxerans.   The pests are more infamous in vineyards, where root-infesting phylloxerans from North America  brought the European wine industry into peril, forcing grafting vines onto imported pest-resistant rootstocks.

See the little rascals inside thei hickory hostel today on our microscopic phylloxeran-cam:


They wiggle within a 100% enclosed chamber.  How bizarre.  How did they get in?  A  pregnant female founded the gall.  It formed around her.  She probably died full of viable eggs, populating the gall with siblings.   What’s so great about living in a bubble?    Protection, no doubt.   What is their exit strategy?   Somehow the bugs induce the gall to rupture.   Hold on there:  They can tell the gall to open sesame and make a portal to the infinite universe?  Apparently so.  And it gets weirder:

Phylloxerans can throttle down the plant’s protective chemicals just as the HIV Virus hobbles our human immune system.  Way back the 1890s biologists found phylloxerans to force the host (grapes) to develop extra stomates.  Stomates are little gas exchange valves essential  for photosynthesis.   More stomates = more photosynthesis = more sugar for the tiny lodgers.  We all know it is silly for a parasite to kill its host.   These wise little parasites understand and go a step beyond, helping the  host to help themselves.


*Galls are growths on plants caused by insects, mites, or fungi.  They are usually larval homes for the arthropod that induced them.


Posted by on March 3, 2017 in Uncategorized


5 responses to “Scrub Hickory and its Inner Phylloxerans

  1. FlowerAlley

    March 4, 2017 at 8:52 am

    Fascinating. Thank you.

  2. George Rogers

    March 4, 2017 at 9:38 am

    Loved the daffodils…so nostalgic

  3. theshrubqueen

    March 4, 2017 at 2:55 pm

    Hickories are one of my favorite trees, if only we had Shagbarks here! You inspired me to start reading about Phylloxera blight and the French Wine Industry, I guess Vitis rotundifolia is not susceptible?

  4. Jacquie

    March 4, 2017 at 7:48 pm

    Love your writings and your sense of humor!

    • George Rogers

      March 4, 2017 at 9:27 pm

      Jacqui…after a cussing barked knuckles evening of trying to unstain a doggie mishap on the wood floor, and trying to fix a worn out door latch…so nice to see something pleasant!!


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