Wednesday, April 13, 2022

Royal Conundrum - Killing the Monarch Butterfly with "Kindness"

The monarch butterfly population has been in serious decline for years now, something many gardeners know. To compensate for habitat loss, gardeners have been encouraged to plant more milkweeds, the insect's larval host plant. But this has led to unforeseen negative consequences, especially in warm winter regions of the U.S.

Native milkweeds can be hard-to-impossible to find, so the tropical, showy "scarlet" milkweed has become ubiquitous in garden centers across the country. This plant, Asclepias curassavica, is native to the American tropics and has spread to pantropical regions worldwide. It has become invasive in some areas, and threatens to become a pest in South Florida. 

Many monarch butterflies harbor a protozoan, Ophryocystis elektroscirrha (OE), that can weaken the adult, prevent the pupa from emerging from the chrysalis, or deform the wings. Monarchs visiting milkweeds deposit spores when they visit milkweeds. Normally, migration culls weakened individuals, and the OE spores die when the plants die back in winter. The plants grow back in spring and summer with fresh, uninfected leaves. But in areas with warm winters tropical milkweed grows all year, thus maintaining high levels of OE spores. Areas of Georgia, coastal Carolinas, Florida and the Gulf Coast have become hotspots of infection.


Monarch on Scarlet Milkweed

Apart from the immediate threat to individual monarchs, year-round milkweed is also, probably more ominously, threatening the migration itself. The presence of the milkweed affects the butterfly's hormonal balance, and works as a trigger to make it reproduce. So monarchs that find themselves in areas with warm winters don't migrate, and a year-round population gets established. With increasing warming trends this area of permanent, sickly individuals will only increase. 

Migration plays a critical role in maintaining a robust gene pool, for it culls badly infected individuals, which simply don't survive the trip. But migration may play other vital roles as well, in ways  we haven't discovered. 

Some organizations like the Xerces Society and the Florida Native Plant Society actively campaign against the use of tropical milkweeds. Some people, though, citing the drastic declines in the monarch population, feel that keeping the numbers up is of primary importance. 

Weaning gardeners away from tropical milkweed is going to be a monumental project, especially since it was promoted so aggressively as a solution to monarch population decline. 



Monarch on Asclepias curassavica

In and of itself, I'm not particularly heartbroken over the loss of scarlet milkweed in our yard. Due to neglect, they've sort of died out this spring anyway. It is a water hog, and the stems quickly get leggy and woody. It also is a magnet for aphids and spider mites, which would make any self-respecting female monarch look for greener pastures. 



Aphid-Infested Milkweed


Finding natives or even native seeds, is going to be a long, drawn out process. Some mail order nurseries offer native milkweed species that theoretically would grow here, but I'd have a better chance with offspring originating  much closer to home. 

Even though they might be the same species, a plant grown in the mid-Atlantic or Midwest would be quite different genetically from one that has adapted to South Florida conditions. They might not even look the same, they might not  survive, and they certainly wouldn't do anything to maintain genetic diversity. Ecologically even North Florida differs greatly from the southern part of the state.



Asclepias incarnata, "Swamp Milkweed," a Native


But there's a further complication!

Whether it comes to weather patterns, the density of bear fur, and many other things, matters often are much more complicated when it comes to the southern peninsula of Florida. It seems that there is an established, non-migratory monarch population south of Lake Okeechobee.  The most-studied migration routes don't cover us, especially on the sw coast, though we might get a few strays. I have had basically year-round monarchs since I began butterfly gardening around 1995. Over the years I have seen newly-emerged monarchs with deformed wings, but not a lot. Even without the scarlet milkweed, all of our native milkweeds might not go completely dormant during our winters, so a small population could persist theoretically without our help. The assumption has to be that the infection rate in our monarch population is close to 100%. 

So, in a way, it doesn't matter whether we keep planting Asclepias curassavica, but it goes against the grain now that I'm aware of a problem. While I don't like the plant, and getting rid of it would not stop the problem of diseased butterflies, it still seems somehow that replacing it with its cousins that "belong here" would be ethically as well as esthetically better. Now comes the hard part - actually doing it. 


Thursday, March 3, 2022

Dune Sunflower - Why Draw

 Dune sunflower, Helianthus debilis, sometimes can be a victim of its own success. It's showy, tough, and flowers enthusiastically year round in frost free areas. A goodly mound of it, with its bright yellow-green leaves, and undiluted yellow ray flowers ringing purple-brown disk florets, brightens up the garden considerably. It wants no pampering. All it asks is space - and there's the rub. 

Space is an increasingly rare commodity in contemporary home sites around here. Lots generally are small, and the houses are built all the way to the 7.5' setback on the sides.( Higher floors sometimes are built all the way out to the property line, curiously reminiscent of medieval street scenes of tall buildings towering over dark, narrow passages). 

The plant is readily available, and some people, municipalities and road authorities have planted it to their chagrin. This is a plant that survives on the pure, sugar sand of Florida's beaches, buffeted by salty coastal winds, and subject to extreme drought while in full sunshine. The average yard, even unfertilized and unirrigated, can be an Eden in comparison, and granted this largesse, the plant takes off.

It doesn't grow as fast as kudzu, but over a period of months a healthy plant will overrun anything in its path, and certainly will outgrow a narrow median strip. Judicious pruning will keep it pretty for a long time. It has to be pruned along the edges, not from the middle, or center. Pruning gets trickier once the  plant has begun to mound over itself. Its long, creeping branches intertwine, so it's pretty impossible to see what belongs to what.

As the plant tumbles over itself, the higher leaves and stems shade out lower levels. A luxuriant-looking mound, may well be completely bare in the middle, with just a veneer of new growth over a scaffolding of aging, woody, leafless stems. It looks atrocious if it is hedged, which is about all most "mow-and go" yard crews know how to do.


Badly "Pruned" Dune Sunflower

This mounding habit makes it particularly attractive in large pots, from which its flowering branches can cascade around it. Eventually the bottom parts of the stem in the pots get woody and bare, which means it's time to cut back hard or pot up another plant. Dune sunflowers transplant easily if they aren't too big. They also root readily and self-sow vigorously if there isn't too much competition. (I wrote more about the dune sunflower in my blog post of Feb. 21, 2021, "January - Not the Greatest New Year.")


All From One Plant, One Pot


 The plant's energetic, uppreaching and semi-vining  habit make it an ideal subject for line drawings. I like drawing better than painting generally. Yellow is a particularly vexing hue for me, because it is so easy to "dirty" it with shading, which destroys its luminance unless you get lucky.


 1-Line Gesture Drawing; Color Study
(Yellow Is Too Light and Greenish)


Part of the definition of line, as it applies to art, is"...an identifiable path created by a point moving in space."("The Elements of Art," J. Paul Getty Museum website: www.getty.edu/for_teachers/building...lessons).

I love this definition because it also seems to denote the action of a growing plant. Attempting to follow that delightful dance of a plant's characteristic energy never fails to engage me.


Dune Sunflower, Pencil Sketch

Drawing is often frustrating and boring, and it requires hours of practice. But succeeding in capturing  movement in the sinuous curve of a stem, or the baroque undulations in a leaf's edge, be it just for an inch, makes all the failed attempts fade into insignificance. I'll never stop trying - and failing -  to get there.

Of course, a line drawing cannot capture the entire being of a plant - in this case, the sandpapery  texture of its leaves, the range of greens and yellows, its volume en masse, even its "non-fragrant" odor. That is a problem of all 2-dimensional media - it can't accomplish everything in one go. But artists and writers of all abilities attempt to capture and communicate something of the innate "truth" of an object or landscape. 


Texture- Dune Sunflower


I looked for answers on "why we draw" on the web, and all I came up with was articles on chemistry -  substances produced by the brain that make us feel pleasure and/or reward. But nothing on why one person is compelled to take pencil to paper while another is driven to put in hours learning to dance, make something, design a building, or throw a ball through a net. Apparently the chemicals are the same, and when you get down to it, they really don't tell us much. And why do some of us want to communicate so badly? It's more than what my husband calls, "teaching your grandmother to suck eggs." It's more like a toddler desperately wanting others to appreciate the wonderfulness of his latest toy. Drawing plants, for me, has something to do with joy, with sharing, with gratitude. But basically, I really can't say.













Sunday, December 26, 2021

Sea Lavender

The first time I saw sea lavender, Argusia gnaphalodes, was somewhere in the Caribbean, possibly Grand Cayman, or Aruba, over 30 years ago. The beauty of its green-gray whorls of silky soft leaves so impressed me that I pinched off a tiny piece and showed it to the agricultural customs agent at Miami International Airport. He identified it for me, and explained that it once had been common along Florida east coast beaches, but was becoming increasingly rare due to development. (Environmental laws give Florida's wetland plants some protection. But some of the most rare and vulnerable native species require high and dry land, precisely the sites most coveted by developers, and often come out the losers).

Argusia gnaphalodes - Tip of Stem


After moving back to Florida in 1990, I began looking for the plant - in vain. So far my sources disagree on whether the plant occcurs naturally on the state's sw coast. Next year I will be stalking local state park and public beaches in search of it. Otherwise, it is native to Florida's east coast north to Brevard County, the Keys, West Indies, Yucatan Peninsula, and the Caribbean coast of central America and Venezuela. 

 Finally, about 2 years ago, I discovered a row of scraggly and generally unimpressive pots of Argusia at the All Native Plant Nursery in Fort Myers*, and pounced. Over the last 2 years it has become a handsome, fully-leafed out shrub about 3-and-a-half feet tall and wide. Barring calamity, it will keep spreading, though perhaps at a slower pace.



Argusia gnaphalodes  - Front View


I planted it in March, several months before the advent of the rainy season. I watered it well for the first week or so, until it seemed to be doing fine on its own, and since then I have neglected it completely, even though it is growing in one of the most difficult areas of our yard - a south-westerly slope of pure sand and brutal daylong sunshine. The summer rains no doubt were crucial to its establishment. 

In fact, gardeners living farther inland, where drainage is not so severe, and salt-laden wind not so common, might have trouble cultivating sea lavender, because it cannot take saturated or highly organic soils. It might also be subject to mildews and molds further inland, where there is less wind - speculation on my part, but possible.

(I have found transplanting native plants during the fall risky. I don't think the plants are programmed to grow in the absence of sustained rain, and stay in a semi-dormant state either until they die or the summer returns. No amount of watering seems to compensate for regular, saturating showers).

Like many plants in the Borage Family, Argusia gnaphalodes is extremely hairy everywhere except the petals and fruits. A dense covering of flattened hairs protects the succulent leaves from dehydration, too much sun and salt. It also gives them the silky softness of a puppy's ear. The leaves reflect silver in bright light, so much so that it's easy to overexpose photographs. In lower light, the plant can appear quite blue. 



Older Flowers - Low Light

Arg-The Latin root of the genus name, Argusia, refers to bright or silver light. The species name derives from a superficial resemblance to a genus of weedy winter annuals in the Aster Family, Gnaphalium.  

The leaves, flat, slightly succulent, and a little spatula-shaped, alternate around the stem, and terminate in a dense whorl. They are about 3-4 inches long and one-quarter inch wide. As the stem elongates, lower leaves die, but don't fall off immediately. Eventually the bottom third of the plant will show these bare stems. The habit may not be to everybody's taste, but I think it makes the plant more interesting. Pendant stems can root, which makes Argusia an important dune-stabilizing plant. 



Backside of Plant - One Stem Starting to Droop

The flowers are formed in a tightly wound cyme, which straightens as the blooms mature. 5 petals, somewhat crinkled, are united at the base. Young flowers are white, with the centers turning pink-maroon as they age. They are said to be mildly fragrant, but so far I haven't been able to catch that. 



Young Flowers


Fruits start out yellow-green, and turn brown or black as they ripen. I haven't seen any ripe fruits yet, so I suspect something eats them before I notice,




Immature Fruits


One of the main reasons this gorgeous plant isn't grown more is that basically nobody knows about it, which is a shame, because for coastal landscapes, it's unbeatable. 



See my blog post, All Native Plant Nursery, April 9, 2020.

Friday, November 12, 2021

Once You Have Goldenrod . . .

 "Once you have goldenrod, you will always have goldenrod," was the cryptic remark of a stalwart in the Naples chapter of the  Florida Native Plant Society when I took home a specimen she had potted. I asked what she meant, and she just gave me a wry smile, and said, "You'll see."

It didn't take too long. Look up "goldenrod" on a search engine and you'll find topics like, " How do I control goldenrod in my garden," and "How do I get rid of goldenrod in my garden."

Besides being tough as nails, the species I got from Freda spreads vigorously by rhizomes. Pot it up, and it creeps out through every drainage hole. Pull it out, and it shows up across the path, or in a neighboring bed after a few weeks. It produces thousands of seeds, but they don't seem to be all that viable, because the plant doesn't jump all the way across the yard, but stays mainly in the general area where I first planted it. Maybe the seeds are mostly for the little creatures that must eat them.  

"Our" goldenrod grows outside the easterly wall, which is remarkably deficient in windows, so I don't have a good idea of what goes on with it. Still, I get the idea that the butterflies and skippers that visit us generally find other flowers in the yard more attractive. On the other hand, I rarely pass by it without seeing some manner of wasp or bee vigorously stuffing itself or collecting pollen. Often there may be several species feeding at the same time.



Paper Wasp on Goldenrod


The plant in our yard seems to fit the description of Solidago fistulosa, "Pinebarren Goldenrod," better than any others, but I'm making no guarantees. There are over 100 species of goldenrod worldwide, and they hybridize readily. On the other hand, according to the 1998 edition of Wunderlin's Guide to the Vascular Plants of Florida, only about 5 species occur naturally in southern Florida, and it doesn't really look like any of the other possibilities.


Goldenrod, Pen & Ink


It doesn't form a classic basal rosette like many members of the Aster Family, including some goldenrods, but just pops straight out of the ground, and reaches for the sky, unburdened by any side branches. Narrow, lance-shaped leaves, sometimes with toothed margins, alternate around a bristly stem. The leaves are attached directly to the stem, with no petioles. As the stem elongates, the lower leaves wither and may or may not fall off.

The inflorescence is somewhat pyramidal, and made up of graceful, arching wands, alternating around the stems, and bearing numerous saturated yellow heads. The heads have both disc and ray florets, but the latter are a little sparse. The stem usually forms just one inflorescence, at its end, but if you cut off a faded inflorescence, the remaining stem sometimes will produce more blooming wands on its sides. It won't make a new, blooming "pyramid." 


Goldenrod Sketch


The stems can get up to 6 feet tall (though mine don't get that high), and the leaves die from the bottom up, so eventually you have a cluster of dead heads and seeds atop a bare stalk irregularly flagged with withered leaves. That's definitely when it needs to be cut back hard, but being a negligent sort of gardener, I rarely do that in a timely manner. This trait could be masked a bit if the goldenrod were placed behind lower-growing plants. Some of ours have spread into a clump of lavender lantana, but it stays too low to hide the stems completely when they get unsightly. 

It's often windy here, and I should stake them. If our yard were bigger, and the  garden beds wider I could let the goldenrods droop,  but as it is, they flop over and obstruct the path, and become something of a nuisance. It's a magnificent plant, and I wish I had space for a grand swathe of it, bending and bowing in the breeze, instead of my constrained, small patch. But I wouldn't do without it. For one thing, it reminds me of the wisdom,humor, and lop-sided smile of a long-dead friend. 



Megachile Bee on Goldenrod




 

Tuesday, October 12, 2021

Twisted-Banded Airplant

 The twisted-banded airplants (Tillandsia flexuosa Sw.) in our yard bloomed most of the summer, and are producing seeds now. This "airplant" is neither rare nor common in Florida, though I suspect loss of habitat is making in more infrequent. It ranges as far north as central Florida, and southward through the Caribbean, parts of Mexico and Central America, Columbia, Venezuela, and the Guianas. It also is a plant of the lowlands, staying from sea level to about 400 meters in elevation. It is quite salt tolerant, thriving in our yard only a few bits  of barrier islands away from the Gulf of Mexico. Some of the plants mounted on small trees got blown 90 -180 degrees off their axes during Hurricane Irma in 2017, but they gradually grew back toward the light. 


Tillandsia flexuosa and pup

The typical plant could be described as "loosely wrapped," with around 10 -15 stiff, leathery leaves arranged in a loose spiral. After the plant has produced seeds it eventually falls apart. The size and appearance of Tillandsia flexuosa vary dramatically, depending on where the plants are growing. The specimens growing in the harsh scrub of the Naples Preserve or Rookery Bay's upland areas are gray/silver, sometimes with tinges of crimson, with darker gray horizontal bands. 


Young T. flexuosa in Naples Preserve


Those living in more shade are progressively a greener gray/almost white, with darker green horizontal bands. The leaves may recurve rather dramatically or remain more upright. I have observed the greatest degree of recurving in plants in fairly deep shade, and suspect it is the plant's way of seeking more light. The plant produces pups, and over time will form a small colony. Given the behavior of the plants in our yard, it germinates fairly easily as well.



T. flexuosa seedlings on Fiddlewood
Do you see the anole?


The inflorescence, which can grow up to a meter tall, is branched, with flowers on alternate sides of the branches. Each branch ends in a pair of bracts, one  normal-sized and one much smaller and sterile.  The bracts and flowers grow at fairly wide angles to the branches - often near 90 degrees, which gives a slightly zig-zag appearance. I imagine that this, and the slight curvature of the areas between the bracts gives the branch greater strength and stability, since the process of flowering and seed production is fairly long. 



Inflorescence


The flowers are a deep, warm pink, and open over a long period, so the plant produces points of intense color, rather than a large display. Once the seeds have dispersed the insides of the bracts reveal themselves to be a deep, rich maroon, which also is attractive. A flower arranger probably would love the dried inflorescences. 





A non-local variety of the plant is viviparous, meaning that the seed germinates in the fruit before the fruit is detached. The mangrove "pencil" is a good example of vivipary. I have noticed seedlings on the dried branches of the inflorescence, and assumed that they had fallen and been trapped by residual fibers, but obviously I need to observe my plants much more closely next year.  The photo below shows somewhat out-of-focus green seedlings on the right of the inflorescence.



 


My first plants came from a legal rescue in the Panther Reserve, just north of the Fakahatchee Slough. Several large trees had been felled to make room for a greenhouse for native orchids, and I and fellow members of a botanical identification course visiting for the day were welcomed to harvest the epiphytes. (The trees were going to the shredder). Since then, I've become an active parking-lot stalker, especially where there are old live oak trees. Usually the fallen epiphytes are the ubiquitous ball moss (T. recurvata L) and wisps of Spanish moss(T. usneoides L), but I've found a fair number of the twisted-banded airplants as well. I haven't found that many lately, so maybe the supply has been exhausted.

I occasionally find pot-belly airplants (T. paucifolia Baker)  and Southern needleleaf (T. setaceae Sw) on or under declining shrubs. I don't take any from a healthy host, but if the shrub is definitely headed for the shredder, I will break off dead branchlets and the airplants. I stopped picking once, because I felt greedy, only to notice the next week that all the plants had been uprooted and replaced, so I won't have as many scruples now when it comes to harvesting from dying shrubs in parking lots. 

Our plants thrive in the shade and branches  of a Fiddlewood. It never has flourished, and I fear it eventually will die, but in the meantime it provides a perfect habitat for the Tillandsias and other epiphytes.


For more on Spanish Moss, see my post on April 12, 2019, "Southern Gothic - Spanish Moss."

See also "Parking Lot Potbelly." Feb. 27, 2019.

Saturday, August 21, 2021

August in the Garden

 I've spent most of my outside hours pulling things out of the yard lately, when the weather allows it.  It's gotten horribly overgrown with lots of  rain and neglect. I'm not the earliest of risers, and the day quickly heats up. The heat and humidity are such that it's easy to flirt with heat exhaustion doing "just one more thing." Some days the relative humidity is just about as high as the temperature. This is summer in southwest Florida, and even though I get uncomfortable and worry about hurricanes, it's my favorite season.

 

I spend a lot of time drinking coffee and staring at a Spanish stopper  through the dining room window. This tree/shrub is unassuming almost to a fault, and since it has a short blooming time, it's easy to miss its "glory days" altogether. But because of my coffee habit, I usually know what's going on with it.



Spanish Stopper, Eugenia foetida



Even the most modest natural things, living or not, can possess an element of striking beauty that is visible only to the passer-by who chances to pause and look. Spanish stopper is a typical wallflower, present, but not noticed. It has rather narrow, vertical habit, so is good for small spaces and hedges. Despite its species name, it does not stink. 

Spanish stopper has its moments of glory when clusters of white flowers clothe the branches. The petals are shell-like and delicate, and the flower itself is adorned with numerous stamens. They are intensely beautiful, even though they have to be observed closely, even with a handlens, to be seen clearly. They make the shrub look like it has been dusted with snowflakes. The flowers don't last very long, especially if it rains, but they are superb while they last. 

One reason our yard is such a mess is that I tend to leave plants that seem "interesting" to me for one reason or other, and a lot of them turn out to be weeds. West Indian pink root, Spigelia anthelmia, isn't the most rampant, and I'm not sure I'd even call it a pest. It's not quite showy enough, even for my taste, to merit cultivation, yet I'm loathe to pull all of it out. The deeply veined leaves are almost sculptural, the tiny flowers attractive, and the general form graceful.

 Dried extract of leaves, roots and stems is available on the Web for homeopathic treatments of nervous disorders and headaches. All parts of the plant are toxic, though. But then again, so are many drugs. It has been used as well to treat worms - hence the species name "anthelmia." As far as I've looked, none of the plants in my yard have had pink roots, not even in cross-section.




Spigelia anthelmia



I have several vines, both planted and uninvited (morning glory) on the fence between us and one set of neighbors. I trim them when they tumble over into the neighbors' space too much. I try to keep the worst of my horticultural untidiness confined to our yard. 


Among the "casualties" of my  pruning were numerous sprays of coral honeysuckle, Lonicera sempervirens.  Native to much of the United States and Mexico, it isn't vouchered for Collier County, but it grows well here nonetheless.  It slows down periodically, but I don't think it every ceases flowering completely. It's a great favorite with hummingbirds and some butterflies. It's on the side of the yard, though, so I don't often see it or the visitors, which is a pity. In this sketch I agonized less about getting the trumpet shaped flowers in correct perspective, and just went for the energy.



Coral Honeysuckle, Sketchbook Pages




Finally, with all the rain we've been having, everything is very green and lush. A few days ago we had the largest flock of white ibis we've seen for a long time grazing in the vacant lots across the canal from us. They will forage unperturbed even in a fairly heavy rain. They've adapted well to the suburban landscape. I don't know how many get poisoned by lawn fertilizers and pesticides, but as long as they stick to the vacant lots they probably are safe. Ibis are common along the beach, too. I don't know whether some prefer salt and some fresh, or whether they use both here. Inland, they would have only freshwater prey, obviously.  Old-time Floridians, like my father, call(ed) them "curlews." There were still a few immature (brown) birds mixed with the flock.




Ibis


This was the quickest of sketches - just an impression of  the birds as they grazed and squabbled. They were gone a few minutes later.
-------------------
I have a longer post about the Spanish Stopper:

I also have a longer post about Spigelia Anthelmia:




Wednesday, August 18, 2021

Mistletoe Cactus

When it comes to mistletoe cactus, Rhipsalis baccifera, there's not much "there" there, to steal a phrase from Gertrude Stein. It certainly is not a show-stopping plant. It doesn't even look like a cactus. Its white berries and slender stalks give it a very superficial resemblance to mistletoe, but mistletoe has leaves and is a parasite, and not even distantly related to cacti.



Pendant Stems of Mistletoe Cactus


Rhipsalis baccifera is an epiphyte that has adapted to the extremes of sea-level mangrove swamps and the high altitudes of the cloud forest, and everything in between. The general assumption among botanists is that cacti are exclusively New World plants, and have evolved relatively recently. Mistletoe cactus fits that theory, being native to 2 counties in southern Florida, the Caribbean, eastern Mexico, Central America and throughout much of tropical South America. But it also is widespread, and considered native in tropical Africa, South Africa, Sri Lanka, Madagascar, and parts of India. How it got there  has had scientists scratching their heads for generations.

  Rhipsalis the largest genus of epiphytic cacti, and Rhipsalis baccifera has numerous subspecies. The classification probably needs cleaning up, but the fact remains that the species is highly polymorphic (appears in many different forms). The vast differences in geography and habitat would account for these differences. It even varies on the cellular level, with most New World species being diploid, while Old World species are commonly tetraploid. 

 Like other so-called "airplants," it uses its roots mainly for anchoring and stabilizing rather than for absorbing water and nutrients. It sometimes also grows on rocks. Trailing stems of my plants have rooted in the upper layers of potted plants standing lower on my shelves, which makes me think that it would creep happily in a layer of humus or porous light soil at ground level. Rhipsalis baccifera, subsp. baccifera is the form found in Florida and much of the New World tropics.

The stems of the Florida native are about the diameter of cooked spahgetti, hence its second common name, "spaghetti cactus." Stems of other subspecies may be thicker, angular, or flattened. The stems can grow up to 9 meters long, though they generally are shorter. My plants have stems only about 2-one-half feet long, but that is because I haven't found a good place for them, and they don't grow as lushly as they should.

The stems hang downward and may branch into multiple stems, which also branch. They are tender and succulent, though become somewhat woody at the base. The main feature that distinguishes cacti from other spiny species is the presence of an areole, a generally raised, cushion-like structure from which the spines arise. The stems of mistletoe cactus have only rudimentary areoles, which tend to disappear with age. With a hand lens you can see a few hairs emanating from these very basic structures. New growth is reddish, and quite spiny/hairy. 



Areoles on Opuntia (Prickley Pear  Cactus)


In all the years I've had my plants, I've never managed to catch them in bloom. That's mainly because I've just left them under a tree or bush and forgotten about them. In fact, I'd forgotten I even had them until  Hurricane Irma in 2017 exposed one clinging for life in a crotch of a defoliated 7-year apple (Genipa clusiifolia). By all accounts the flowers are small and insignificant, though with the aid of a hand lens, "insignificance" sometimes can spring into beauty. Translucent whitish berries are borne directly on the stems or on a very short stalk. Birds eat the berries, helping to disperse the species. 



Adventitions Roots, New Growth, Rudimentary Areoles


In fact, the plant is so unassuming, yet vexing in its variability, that a specialist named Ken Friedman wrote, "So many species are named R. baccifera that it is almost impossible to tell an original. Four or five  growing in my greenhouse  have different vegetation although the flowers are similarly inconsequential. If anything, they are large weeds that take up more room than they are worth." 

So how did this modest plant colonize such a large portion of the globe? The theories that exist are not exactly convincing on their own. 

The least likely theory is that the  plant was spread by the shipping trade in the 15th century and onward. But the plant is widespread into interior regions of the Old World, and not limited to the port areas. That kind of spread normally wouldn't occur in a matter of hundreds of years. Even more problematical is the fact that Old World subspecies differ significantly from the "ur-type," R. baccifera, and such evolution normally requires eons, not centuries to occcur. The plant also is prominent in Ayurvedic medicine, which some believed began as early as the Bronze Age. It is possible that it was a later addition, but it still takes a long time for something to become entrenched in regional  medical lore.

The next theory involves continental drift. This theory holds that the plant was well-established before the breakup of the supercontinent Gondwana. The fly in the ointment here is that Gondwana probably began to break up around 180 million years ago. If cacti as a group didn't evolve until some 30 million years ago, as is generally accepted, that leaves a huge gap. In that case Rhipsalis would have to be an atypical, extremely ancient genus. Since cacti leave few, if any, fossil records, nobody really knows when Rhipsalis evolved, but it probably was well after Gondwana's destruction.

That leaves us with birds, which we know are frequent vectors of plant dissemination. It certainly makes sense for the distribution within the New World. Many of Florida's native plants were brought by birds  from the Caribbean and the Bahamas. A problem with this theory is that most birds migrate north to south or the reverse. I'm not aware of any seed-eating birds that currently migrate over the Atlantic from the Americas  to Africa and beyond. That would be a vast distance for a seed-eating bird to traverse, and also a vast distance for a seed-eating bird not to poop. We don't yet have any fossil record of any ancient bird prototype that would have been up to the trip either.

The "answer," if there is one, is probably a combination of continental drift and the birds. The breakup of Gondwana didn't exactly occur overnight, but over the course of millions of  years. In fact, we are still moving. What eventually became Africa and South America would have been much closer at varioius points in geological history than they are today, and there most likely would have been islands and mountaintops that are now submerged or destroyed. Then island-hopping by birds would make sense.

Personally, I rather like the "space aliens" theory put forward by "Laidback Gardener" Larry Hodgson, who suggests that, "millions of years ago, space aliens moved the plant around, just to mess with scientists trying to understand how R. baccifera got around." Why not?

Further Reading:

The Cactus That Traveled the Globe.Larry Hodgson. Http:/laidbackgardener.blog/2018/12/03/the-cactus.://


Rhipsalis baccifera (JS Meuller) Stern. In Cactus Journal (Croyden) 7:107 (1939). With comments and photographs by Ken Friedman. www.Rhipsalis.com/species/baccifera.


I Havana a Clue How I Got Here; Cactus Goes for a Drink in Cuba, Wakes Up in Cape Town. Jan. 27, 2014 by alieyres. http://blogs.reading.ac.uk/2014/01/rhipping-yarns.