The Quiet Invaders—Death by a Thousand (Literally) Cuts

Shoebutton Ardisia. Once popular in gardens, this Ardisia is related to and has been mistaken for the native Marlberry. (By JB)

In Palm Beach County:

Grasses: 135 total vascular plant species growing wild, 45 species non-native, 33% non-native

Sedges: total 83 total, 13 non-native, 16% non-native

Asteraceae: 95 total, 18 non-native, 19% non-native

Rubiaceae: 23 total, 7 non-native, 30% non-native

All Florida Vascular plants: 4289 total, 1421 non-native, 33% non-native

(Data from USF Atlas of FL Vascular Plants)

Every nature enthusiast decries the invasive exotic bioinvasion of Florida and worldwide. Brazilian Pepper and Climbing Fern make us cuss. We battle unwelcome Laurel Figs and Pineapple Guavas on public lands. We grouch about those who love their beachside Casuarinas. And then come the Pythons, Walking Catfish, Cane Toads, Cuban Treefrogs, and snails that look like tennis balls. (Are these good for Limpkins?) Invasive microbes and arthropods are a scourge. We know, we know.

But it is even worse than it looks. For every invasive species we know many more sneak in virtually unnoticed .

A quick and approximate survey of species growing “wild” in Palm Beach County makes the point painfully. Looking at four large plant families—the grasses, sedges, composites, and coffee family, the percentages of non-natives species are 33, 16, 19, and 30. Eighty three non-native species in Palm Beach County alone. Or statewide 1421 non-native species accounting for 1/3 of the flora. We have more invasive exotic species growing loose in Florida than the number of native species in Hawaii!

Cuban Bulrush forms floating mats. (JB)

I don’t have data, but 1/3 of a diverse flora being non-native begs unanswered questions concerning crowding, allelopathy, competition, hybridization with native species, alterations to the soil ecosystem, impacts on wildlife, altered fire patterns, collateral pests and diseases, and more. Is Global Warming a factor?

So it’s not all Melaleuca. And, by the way, Melaleuca’s close relative, a garden favorite, Weeping Bottlebrush (Callistemon viminalis) is adding its red beauty to certain natural areas in Florida. Why don’t we just dub it Bloody Melaleuca?

Some of the invaders are pretty, or novel, and interesting. The other day I waded into a canal for a better look at an overhanging branch bearing what I thought was Skunk Vine (Paederia foetida) in a new locale. Wrong! (I hate being blind.) But you might not have to wait long to enjoy Skunk Vine on a branch near you. The flowers are showy. And even more fun nomenclaturally, and so far limited to the Miami Area, is Sewer Vine, Paederia crudasiana, which, I’m sorry to say, makes me wonder what a crud-ass looks lie. (Sorry, blog-writer’s license)

Skunk Vine is prettier than its name. (GR)

Speaking of runaway vines, Mile-a-Minute Vine (Mikania micrantha) is pondering the possibility of over-running Florida from a start in Miami. Why has it remained localized so far?

Trying to figure out which ferns are truly native is next to impossible. If you think otherwise, compare every source you can find dealing with the genus Nephrolepis. If you get it figured out definitively and with consensus, please let me know. And to make it worse, fern spores blow long distances on the wind, and ferns are especially good at hybridizing.

Native Boston Fern? No, invasive Asian Sword Fern. Mighty similar! (Boston Fern has light tan shagginess sticking out on the leaf stalk.)

So what can you do? Bulldozers, machetes, brigades of volunteers and herbicides are not enough. I heard someone say recently, “sometimes all we’ve got is resignation.” Just like crime and reality TV, we’ll never shed the curse, but at least there is one little thing we could do:

Abandon the 19th Century social cachet attached to “I have an exotic plant you don’t have,” and mature to a 21st Century preference for the native species that belong in our own back yards. Oh yea, right, I’m preaching to the other preachers.

“Mexican Petunia” is not Mexican, and is not a Petunia. It remains popular in landscapes despite being a Category I Invasive Exotic.

 

The Disappearing Native Bird

“The Florida Scrub-jay is one of North America’s most endangered birds” – that’s the opening line of the Jay Watch Volunteer Training Manual.  Every year in the middle of June volunteers monitor jay populations at more than 40 conservation sites from northern Volucia County to Palm Beach County in the southeast and Sarasota County in the southwest.  In the year 1992 there were 11,000 individual Jays counted and by 2011 only 6,500 were found.  What is most disturbing is that there was a 26% decline on protected lands.

Greg Brown, Ranger at the Savannas Preserve State Park, calling the Jays.

 

At a yearly Jay Watch meeting volunteers are taught monitoring procedures and are encouraged to become familiar with particular sites.  Since Scrub-jays are territorial, each monitoring site is visited 3 times over a one month period, at varied times of the morning.  This schedule increases the likelihood that all birds will be counted.  A CD of Jay scolding calls is played in 4 directions at least 3 times in hopes of bringing the Jays close enough to identify individual birds.

Chris Vandello, Biologist at the Savannas Preserve State Park, identifying the Jays.

 

By July, fledglings will still have their brown heads and previously banded adult birds will have rings of color on their legs.  The different colors allow volunteers to ID specific birds and follow them if they move to other territories.  Many Jays stay in their home territory for several years and help raise the next year’s babies as well as protect the borders from Jays trying to move in.  Unbanded adult birds are also noted and will eventually receive special training to ready them for the bander.

When volunteers play the scolding call, the Jays come quickly, ready to defend the borders from interlopers.  Volunteers document flight directions as well as colored leg bands.  These bands fade or are lost over time and become difficult to read correctly.  Several people working together can help to verify the colors.

Each banded bird carries 2 colored bands on their right leg as well as a uniquely numbered aluminum US Fish and Wildlife band on the left.  A colored band is also placed on the left leg for a total of 4 bands.

Adult Scrub-jay with purple over red and a silver band. One band is missing.

 

All Scrub-jays do not live in state parks.  There are many hanging on in small scrub areas where development has encroached on their territory.  You can help by:

• Reporting any Jays found outside of a park. Call the park or preserve closest to you.  It is also helpful to report any bands on their legs.
• By securing your cats on your own property.  Many fledglings are killed by cats allowed to roam.
• Educating your friends and family about the plight of Florida’s Disappearing Native Bird.  Maybe, just maybe we can stabilize the numbers that remain.

 

Hickory Dickory Dock, Old Hickory, and Hickory Sticks

Carya species

Juglandaceae

You can scarcely find a group of trees more steeped in American lore than hickories, but let’s not be American-o-centric in the era of globalization. Hickories are native to China, Viet Nam, and Laos too, being examples of the sister-species relationships linking  Eastern U.S. and East Asia.  I wonder if there’s a Euell Gibbons-type guy in China who savors wild hickory nuts there.

Water Hickory nuts (by JB)

The best hickory nuts are Pecans,  cultivated in the southeastern U.S., and  speaking of China, likewise there.   We even have some cultivated in Palm Beach County, although the native region is somewhat farther north.  The native range of Pecans is actually somewhat unclear, thanks to ancient peoples’ taste for the nuts.  I’ve seen them growing wild in lowland woods along the Mississippi River.

The name Hickory comes from an Algonquin word for a milky paste made from pounding the nuts.

Water Hickory in Riverbend Park (I don’t know who took the photo)

Hickory wood is ultra-strong, durable, and snappy-bendable.  They used to make golf club handles from it, and hickory clubs are enjoying a little retro-chic nowadays.  Today I read a (1936) article on how to select the strongest hickory hammer handle.   There is hickory flooring and hickory furniture.  Pre-Europeans and modern bowyers could debate whether hickory is the best wood for archery bows. (Osage Orange and Yew would have loyal proponents.)  The list of hickory products could go on.  In addition to tasty nuts and tough woods, hickories are beautiful.   I’ve spent a lot of time in the Appalachians and in the Ozarks, and life just wouldn’t be the same hickory-less.

Fore! (Photo stolen from Internet)

The good news is that here is South Florida, contrary to all that “tropical paradise” nonsense, we have two lovely hickories: Water Hickory (Carya aquatica) and Scrub Hickory (Carya floridana).  The two names hint at the interesting part of today’s topic.  Our two hickories couldn’t be farther apart ecologically.  Water Hickory lives up to its name by being a soggy shore and swamp species.   (A great place to see them locally is Riverbend Park in Jupiter.)  Its natural range is across the southeastern U.S.

Or if sun-baked sugar sand is more to your liking, Scrub Hickory is the one for you.  This odd tree lives in high dry scrub, where it can be the dominant (or only) broadleaf tree.  Its distribution is limited to the Florida Peninsula.

Carya floridana. Bud. Hickories have big messy distinctive buds. (JB)

You might wonder if two species found jointly down here in South Florida are close relatives.  No.  They are in separate sections of the Hickory genus Carya.   Water Hickory  is related to and hybridizes with Pecans, which are naturally a swampy species.   Scrub Hickory, by contrast,  is related to the common widespread  Pignut Hickory (Carya glabra), which lives (among other habitats) on high dry “scrub-ish” places.

Time to speculate.  Carya aquatica is a widespread species that probably wandered from the more northern states into Florida in ancient times.  The history of Carya floridana is more fun to imagine.  It is restricted to Florida and probably evolved here.  Most of Florida has been inundated too recently to have much ancient evolutionary history, except on scrub which differs from the rest of Florida by having been high and dry vastly longer then the lowland regions favored by Carya aquatica.   Scrub has been high and dry long enough for plenty of evolution.  Now to repeat,  this is speculation, not fact,  but  Carya floridana perhaps originated  on scrub as an isolated southern satellite population of Pignut Hickory, Carya glabra, which is variable and widely distributed in Florida, although not this far south.   Florida scrub areas were figuratively and literally islands as sea levels rose and fell over the eons, the perfect setting for an isolated splinter-group from a more broadly distributed species to evolve into a separate species in its own right.  Interestingly, these two species (and some other related hickories) have the same tetraploid (doubled)  chromosome number consistent with close relationship.

 

Alligator Weed, a Taste of the Amazon

Alligator Weed

Alternanthera philoxeroides (not native)

Amaranthaceae

Having a drainage ditch behind your hose can be entertaining and a chance for expanded vistas on nature right there in the (sub)urban yard. Thanks to my waterfront real estate I’ve seen all the big beautiful wading birds and their duck companions, a hawk snag a snake, jumbo catfish, darting minnows, and dragonflies. The frogs sing at night. I’ve learned that young cottonmouths go out to party with yellow tails, that kids still go fishing, and that dogs enjoy a swim off the leash. All the sedge species in town form a spontaneous garden along the banks. Much fun for a reviled “no trespassing” ditch.

Which will fill the ditch? Alligator Weed or Torpedo Grass? The race is on.

The aquatic lifeform grabbing my attention now is a little taste of the Amazon: the invasive exotic South American Alligator Weed. Take my word for it—that weed grows like a weed! I feel like I can see a difference from day to day. The plant can take over big areas fast, as multiple published studies have affirmed and reaffirmed. That has prompted interest in biocontrol, with limited success, especially by a Brazilian Flea Beetle.

CLICK for biocontrol

Anyone who lives near warm eutrophic shores can attest to the fact that the species is not under control.

The rate of growth is interesting but where it grows is the good part. The stems spread out on the water surface like a swimming snake, and raise their growing tips or flowering tips a little above the water. To accomplish this the stem is hollow. The growing tip and first few nodes jutting out of the water are only a little swollen. Somewhere around 5 nodes back from the apex the stem expands abruptly to many times its original diameter; it looks puffy like it was inflated with gas. The nodes produce branches and wads of roots, allowing the sprawling branches to suck nutrients directly out of the water, and allowing the branches to root in the mud if the water level drops.

Although Alligator Weed can produce seed, there is a suspicion that its spread in Florida and other introduced areas is by cloning. What is easier to propagate than a species where the stem segments break off and float away pre-rooted and ready to invade?

The rampant growth, easy propagation, and nutrient-sucking power have suggested to multiple observers that this invader may not be 100% bad…that maybe it can be harnessed to pull polluting nutrients, including heavy metals, out of polluted waters. Also, people and livestock eat Alligator Weed, which helps explain its intercontinental spread.

The stem puffs up a few nodes back from the tip.

The flower heads may remind some readers of Globe-Amaranths or Joyweeds. That’s because they all belong to the same family, the Amaranthaceae.

A lot of folks worry about some form of coming collapse of civilization. They stockpile sardines, bullets, and gold. I’m not worried—when the going gets rough I’ve got water-purification, biofuel, and unlimited salad right in my own back yard, with absolutely no effort.

 

Way Down Yonder in the PawPaw Patch

PawPaws

Asimina species

Annonaceae

My best memories of my father come from his profound love and knowledge for nature, but even the sweetest memories can have PawPaw problems. My family lived in West Virginia, home to magnificent Pawpaws (Asimina triloba) 20-30 or more feet tall rising from the sides of shaded ravines and stream bottoms. (Where did the repeated Google-assertion that Asimina tetramera is the tallest pawpaw in North America”come from? Asimina triloba is much larger. I thought they couldn’t put anything on the Internet if it isn’t true.) My Dad told me, somewhere around age 8, ca. 1959, that PawPaws are tasty treats, so I sampled one out on the hillside where a burning coal slag heap looked and smelled like Hell surfacing. Within seconds after munching the “mountain banana” I was unconscious, to wake up a few minutes later in a pool of my own vomit. For the subsequent 53 years and to this day I can’t smell a Pawpaw without having my stomach flop. Was the PawPaw green and mean? (I can’t remember.) Was it an allergic reaction?  Perhaps. Here is a tidbit lifted from Google:

“Allergenic responses have been observed. While many people enjoy the taste of pawpaw, some individuals can become sick after eating the fruit. Skin rash, nausea, vomiting, or diarrhea can develop…Many tissues of this tree, especially bark, leaves, and seeds, contain a variety of alkaloids such as the aforementioned acetogenins, as well as phenolic acids, proanthocyanidins, tannins, and various flavonoids. Though these compounds represent potential commercialized products as anticarcinogenic and botanical pesticides, they also can cause allergic reactions.”

The name PawPaw is confusing, applied also to Papayas, so be sure we’re talking about the approximately 10 species of the genus Asimina limited to North America, half of them limited to Florida as scrubby shrubs. The species have a long-known history of hybridization, yet, with that in mind, a surprising freedom from the taxonomic rearrangements often encountered with rampant hybridization.

Four-Petal PawPaw near Jensen Beach (by JB)

PawPaw flowers are odd, and sometime showy. I’ve seen them misidentified as Orchids, although quite a stretch, the error is understandable. Traditionally regarded as primitive, the blossoms tend to be unusual for Dicots in having sepals and petals mostly in multiples of 3. The stamens and pistils are numerous and separate, with the pistils pollen-receptive before the anthers of the same flower release pollen.

Four-Petal PawPaw in April (by JB)

What’s more interesting is that the flowers are generally regarded as beetle-pollinated, a slightly unusual and “primitive” characteristic. As with other beetle flowers, they tend to be cup-shaped and they can smell funny and fermented, although highly varied, and no doubt delightful to a beetle. Crawling around in the scrub sand Friday John and George found a beetle within the flower of a Four-Petal PawPaw. PawPaw flowers combine various shades of white, purplish-reddish tones, and greenish-yellow. The petals can increase in size and can change color after the flower opens, to the point that the same individual seen at different phases could pass for two different species.

We opened the flower with a little force for a clear view (by JB).  The lumpy white ball at the center is a mass of stamens.  The green structures poking out at the center are pollen-receptive stigmas.

Four-Petal PawPaw is one of the two species scattered in our usual working radius, in fact, its entire worldwide distribution almost matches our usual working radius along central-south coastal Florida. How many federally listed endangered species do we have restricted to that zone? CLICK  It’s easy to recognize in the field because somebody has usually affixed blue flagging tape to it. Don’t trust the name “four petal” PawPaw because names can lie, and the distinctions between sepals and petals can be confusing too. Premier Florida botanist John Kunkel Small named the species in 1926.  He might have missed this critical reference: CLICK
As with many rare and endangered species, I worry about too much love almost as much as I worry about too little attention. Rare species have unique and interesting population structures and genetic patterns with respect to their odd distributions. And this is especially true as DNA study allows high-resolution analysis of genetic-distributional-relationship histories. Thus sometimes maybe propagation by botanical gardens and reintroductions of clones might mix up some delicate evolutionary genetics. So call me a grumpy silly old worrywart nervous nelly.

Does it look like an Orchid? (Naw)

The other species abundant in our botanical sandbox is Reticulate-Leaved PawPaw (Asimina reticulata) often encountered with big white floppy flowers on leafless (or leafy) stems poking up from the scrub sand. The fruit can look like a bloated banana and certainly must be pleasing to wildlife. Even tiny wildlife can join the “feast,” because the individual seeds have their own pulpy attachments (called arils). (However, personally I’ll take a raincheck.)

Asimina reticulata fruit.

 

Taking a Shine to Varnishleaf

Varnishleaf

Dodonaea viscosa

Sapindaceae

Here’s a shrub for everyone, and I do mean everyone around the world. The shrub we call Varnishleaf in Florida must have a few names we can’t pronounce because its natural distribution ranges from here to Australia and back. Actually the other way around, since DNA research shows its origins to be Down Under. The international uses are as widespread as the cosmopolitan places, everything from making the hard wood into weapons to more medicinal applications than you can throw a pill at. In Florida we like this species as a tough drought tolerant landscape shrub with pretty fruits.

John and I did not go visit Australia to see Varnishleaf. There is plenty in the Hobe Sound National Wildlife Refuge cooking in the sun up on top of those sugar sand dunes.

Varnishleaf (by JB)

The puffy papery fruits resemble those of certain garden trees, especially Goldenrain Tree (Koelreuteria elegans) or Black Pearl (Harpullia arborea). Some readers will see “the same” fruit in species of Cardiospermum. The similar-pod list could expand, but why bother, the point is family similarities in these members of the Soapberry Family, the Sapindaceae.

Varnishleaf pods (by JB)

The predictable lists of “traditional medicinal uses” surrounding most common widespread bioactive plants can grow a little dubious and tiresome. Conduct a little research and you will find almost any plant you name to have served somewhere somehow to counter some common discomforts.

That cynical remark off my chest, a traditional use for Varnishleaf struck me as unique and particularly plausible: warming the naturally sticky leaves and applying them as a plaster over hurty places. Given evidence of antimicrobial activity, maybe sticky Dodonaea plasters actually help with healing. Free Salon Pas. Dodonaea seems to contain multiple bioactive contents, including saponins, cyanide, and more. Saponins are lathery-poisony compounds that put the soap in Soapberry. They are most famous as fish poisons.

Why would a shrub make shiny “varnished” leaves anyhow? Here we have a leaf with an array of adaptations for extreme sun. In Mexico Varnishleaf is a member of “Opuntia associations.” (Opuntias are Prickly Pear Cacti.) Come to think of it, right here in Florida Varnishleaf can be a member of the Opuntia association. This is a plant for blazing sun. So then an obvious guess about those ultra-shiny leaves is the same as mirrored sunglasses—to bounce away excess light and protect delicate tissues beneath. Seen microscopically, the top layer of the leaf has special varnish-making cells just beneath the surface. Plant ecologists Gary Brown and Bruno Mies commented on a related adaptation in the same species…the ability to orient the foliage vertically to minimize sun exposure. Also odd, the layer of photosynthetic cells near the leaf surface is thicker then in most leaves—a leaf designed for fun in the sun.

Varnishleaf leaf (by JB)

The fruits are showy and novel, whereas the flowers are merely novel. Apparently pollinated by wind, they have no petals, but rather many pollen-dispersing anthers, and extended pollen-catching stigmas.

The flowers—no petals, just the “business parts” (by JB)

Did you gulp at the idea of one species distributed from New Zealand to Hobe Sound? Varnishleaf has two outstanding abilities behind its wanderlust: 1. High salt tolerance. It can grow among mangroves. 2. The world’s toughest seeds. Experiments have shown high germination rates after 6 months in saltwater. Those little bitty seeds can float across vast oceans, perhaps sometimes within their capsules, and maybe sometimes aided by seed-eating migratory birds. Some of the seeds have an internal airspace.

Badass with Dodonaea-inspired shades (Photo not of or by JB)

 

Pectis

Cinchweed

Pectis glaucescens

Asteraceae

Friday John and George invaded the historic site of the demolished LORAN station at Jupiter Inlet, now known as Jupiter Inlet Natural Area, a beautiful and botanically rich scrub moonscape extending down from the sugar sand dunes to the Intracoastal Waterway, with the Jupiter Lighthouse rising above the distant trees.  The best-smelling species in full bloom was the Willow-Bustic buzzing with bees.  Its flowers  are curious, but for another day.  More subtle and underfoot, likewise in full bloom in a mat on the sand was Cinchweed, Pectis glaucescens, a curious tiny representative of the Aster Family.  This little wildflower may tower to an inch tall with a golden flower head a quarter-inch in diameter.

Pectis flowers (by JB)

When not in flower you might notice Pectis by its fragrance as you crush it underfoot, pungent and pleasant (to my nose).  Some folks compare it to Citrus, although to me it smells like “Asteraceae.”   Hold the leaves up to the light and see the oil glands big and translucent, in this way reminiscent of Citrus in appearance as well as aroma.  In at least one species of Pectis the fragrant oils are apparently the same as those derived commercially from cumin, caraway, and dill seed, and thus of potential commercial interest.  Anything that smelly has had medicinal uses, and Pectis has served against ailments ranging from fevers to  eye ailment.    They’ve also been used as food flavorings, and even as perfumes.

Pectis on the sand (by JB). See how the colony spreads.

The leaves give the genus its name, because they are “pectinate,”  meaning resembling a comb, or a fish skeleton in outline.  (Not always conspicuous on P. glaucescens.)

This sand-dweller has specializations worth mentioning.  Certain plants of hot sunny places have what’s called “C4 Photosynthesis.”  Setting the biochemical physiology aside, this is a mechanism with associated cellular anatomy to overcome photosynthetic impairment most plants suffer under hot conditions.  Most C4 species are hot-climate grasses, such as Sugar Cane.  The adaptation is uncommon in broadleaf plants, but here we have an example, encountered fittingly in hot sunbaked habitats.  Some Pectis species live in deserts.

Uproot a Pectis mat and it has a curious structure, shaped like a big green tack.  The top of the tack is the green spreading foliage mat almost flat against the sand.  The pointy part of the tack is a single (or few) taproot(s) at the center of the mat and drilling down into the sand.   The outer fringes of the mat spawn  little satellite colonies able to root and take hold on their own.  Clone-colonization is significant in the sterile Pectis Xfloridana mentioned below.  Stay tuned a moment.

Upside down Pectis. Check out that taproot! (By JB)

Florida is home to multiple Pectis species, one of which has a special relationship with today’s Pectis.  Pectis prostrata (flower heads not on a stalk, vs. the long stalk in P. glaucescens)  hybridizes with P. glaucescens to make a sterile hybrid with abnormal chromosomes called Pectis Xfloridana.  Pectis prostrata gets around, being an invasive weed in China.