by Carrie Stevenson | Mar 10, 2022
Twigs dangle from a branch, held in place by horsehair fungus rhizospheres. Photo credit: Carrie Stevenson, UF IFAS Extension
Imagine walking through the woods, enjoying the fresh air and birdsong, when you notice a twig just dangling midair. On first glance, you might presume it is stuck in a vine or a large spider web. However, this material is thinner than a vine and there are no spiders or webs to be found. On closer inspection, you see the twig is entangled in a dark knot of string, slightly thicker than a human hair. Following the source of the black string leads to a lacy network of the same material, flat against and around the branch from which the twig hangs. Fifteen feet down the trail, you come across the same thing—more twigs hanging from “string” in the trees, dangling from a knot of thin black material. What is going on here?
After some research, my conclusion is that we have come across horsehair fungus (Mirasmius spp). Mushrooms and other fungi have long, thin, rootlike structures called rhizomorphs. Rhizomorphs are composed of large numbers of microscopic hyphae, which are tubular and exchange nutrients and water among other parts of the fungus. The hyphae are typically located underground, but in this instance, they are visible in the open.
The ropy network of rhizospheres is visible on the branch, then turns into thin fibers that can trap plant debris. Sample provided by Suzy Marshall.
Aerial rhizomorphs are an excellent example of an evolutionary strategy known as resource partitioning. By forming a netted trap to intercept falling leaf material on a tree, the fungus gets a jumpstart on the decomposition process, taking nutrients from dying plant material before it falls to the ground. The tree-dwelling fungus is thus not competing directly with fungi on the ground, and both types of fungi can thrive. In human terms, this is loosely analogous to co-workers labeling their own food in a shared refrigerator. Everyone eats, but no one has to compete with another for nutrition.
A bird’s nest in Argentina is composed primarily of strong horsehair fungus fibers. Photo credit: Danny Newman
The common name, “horsehair fungi” applies to many species around the world. They are most common in nutrient-poor subtropical and tropical forests, where any available nutrients in the soil are used up quickly by the lush tree growth. They can be found here along the Gulf Coast, up to the Appalachian Mountains, and as far away as equatorial rainforests. In a Malaysian study, researchers found that the aerial fungi trapped up to 225 pounds of fallen plant material per acre! This network of material also supported a significant population of arthropods, which were crucial parts of the overall ecosystem by providing pollination, herbivory, and serving as detritivores. One study of spruce-fir forests in the northeastern United States showed that birds are known to use the material as a nest lining, as it is lightweight but very sturdy. In this particular research, 85% of the nests (particularly of warblers and thrushes) examined utilized the material.
by Stephen Greer | Apr 15, 2021
There is a tall stately tree that can be found throughout the southeastern states, native in nature with a lustrous green leaf the southern magnolia is like no other tree. This amazing tree can be found from the edge of deep woodlands to the back of the tall sand dunes in the panhandle of Florida, all the way down the Florida Peninsula. The leaves provide a consistent evergreen providing a year-round presence in the landscape. Spring brings up small plate sized creamy white blooms with a wonderful fragrance with multiple blooms opening over 3 to 5 weeks. The magnolia can serve as a specimen tree or a back drop to allow other plants to be enjoyed.
Magnolia Tree in the Landscape. Photo courtesy Stephen Greer
Often the magnolia is envisioned to be this 80-foot tall by 40-foot-wide tree with an upright pyramidal shape with the branches reaching to the ground and up to 8-inch-long shiny green leaves. There are other shapes and sizes in the landscape industry that have been found in many different ways from seedling research that has taken place at several of our land grant universities including the University of Florida. Other magnolia with different growth and bloom habits have been found growing in nature. Below are a few of these exceptional species that were selected by the keen eye of a nurseryman or a plant specialist. Next come decades of field grown observation to determine if the plant characteristics are consistent with cuttings taken and rooted to grow more trees. This is one way to see if the same look and growth continues in multiple plants.
Magnolia Bloom. Photo courtesy Stephen Greer
If you grow trees from collected seeds, the new seedlings will show variable growth patterns and likely not present a consistent growth or leaf form from tree to tree. This is the reason for taking cuttings from a magnolia with the desired growth habit, leaf size and color, bloom color and fragrance.
Several cultivars have risen to the top in popularity in the landscape industry over the last 30 to 40 years. One of the most popular large magnolias is ‘Bracken’s Brown Beauty’. It was selected in a seedling field when one of the universities had completed research and invited a local nurseryman to come take any he wanted before the field was turned under for other plant research. Many were dug and field planted at the nursery with one showing many desired characteristics. With its dark rusty brown lower leaf and deep green top. It was observed for a number of years with cuttings taken. One major observation was its tolerance to cold weather. They had a winner and began to introduce it into the plant industry. ‘Little Gem’ is another magnolia that is quite popular for its dwarf (slower) upright growth habit. It first was considered a hedge plant with a dense leaf canopy from bottom to top. The challenge is the plant density opens up as it matures with it ultimately reaching approximately 30-foot tall by 20-foot wide. The surprising part of this smaller magnolia is its bloom is similar in number, yet 3 to 5 inches in size in large numbers as the other southern magnolias. Next there is a few weeks rest period and then sporadically blooms all summer and early fall. There are so many magnolias that could be mentioned I just don’t have enough article space, so it will stop with ‘Claudia Wannamaker’. This magnolia is an old stand by that has been found to be moderately salt tolerant and can be found growing near coastal settings. The leaf wax layer is slightly thicker allowing for a little more protection from the salt. It has a more open multi-truck growth allowing for wind to pass through more easily. The challenge is finding one in the landscape industry.
Contact your UF IFAS Extension office in your county with questions. Enjoy this wonderfully unique tree.
by Taylor Vandiver | Jun 15, 2015
As summer comes to its apex you may find yourself longing to move your activities outdoors and commune with nature. However, as you are reveling in the warm weather while hiking, camping, biking, gardening, etc. remember that there are native plants of a less friendly nature hiding in plain sight. I’m sure you have all heard the tried and true mantra “Leaves/leaflets of three, let it be”, we suggest you hum that to yourself as you head outdoors in order to save yourself from the consequences of an accidental poison ivy encounter.
While I am not a native of Florida, I grew up in the Deep South and I have had many dealings with our aforementioned foe. Poison ivy (Toxicodendron radicans) is a native to North America which contains an oil known as urushiol. This oil can cause a severe skin rash (dermatitis) when any part of the plant is contacted. The reaction and rash, in susceptible humans, usually starts with itchiness and swelling, followed by the reddish inflammation of tiny pimples or formation of blisters at the areas of contact. The rash can begin as early as an hour after contact or up to five days after contact. All parts of poison ivy, including the hairy-looking aerial roots, contain urushiol at all times of the year, even when bare of leaves and fruit in winter. An allergic reaction can occur by touching the plant directly or indirectly contacting it through animals, tools, clothing, shoes and other items. Also, be aware when preparing your campfires and bonfires that the smoke from burning poison ivy contains oil particles that can be inhaled and cause lung irritation.
A picture of poison ivy with its characteristic 3 leaflets.
Now that you know the consequences of coming in to contact with poison ivy, let’s talk about where you can find it and how it can be identified. Poison ivy can grow in shady or sunny locations throughout Florida. It’s habit can be a woody shrub up to 6 feet tall or a vine up to 150 feet tall that climbs high on trees, walls and fences or trails along the ground. Leaves emerge with a shiny reddish tinge in the spring and turn a dull green as they age, eventually turning shades of red or purple in the fall before dropping.
Poison ivy has little or no effect on animals, but, as we discussed, they may carry the irritating substance on their hair and thereby transmit it to us more susceptible humans. Not only are the berries attractive to birds, but the leaves and fruit are also an important food source for deer.
Poison ivy is often confused with another native, the Virginia creeper (Parthenocissus quinquefolia). However, this trailing or climbing vine can be distinguished from poison ivy rather easily by its five divided leaflets. Also, Virginia creeper has blue-black berries and tendrils that end in tiny sticky pads that attach to trees and other surfaces.
So, what methods of treatment are available to those who suffer the wrath of poison ivy? If you suspect that you have come into contact with poison ivy always wash your skin with strong soap and cold water immediately! If you scrub with hot water you will open up your pores and let the oil into your skin, causing further irritation. Remove and wash all clothes, including shoes and socks in a strong detergent and warm or hot water. Keep your hands away from eyes, mouth and face. Don’t scratch the rash! To soothe the itch apply calamine lotion, zinc oxide or other doctor recommended products. Always call and visit your doctor if these measures don’t work, you know you are highly allergic or the rash persists.
So, how can you stop poison ivy at the source and avoid these painful symptoms? The first approach would be to eradicate an area by hand removal. Anyone who is extremely sensitive to the oil should ask for help when removing these plants. Always wear proper clothing that covers all areas that could potentially come in to contact with the plant. Also, lotions and creams containing the active ingredient bentoquatam can be used before the weed whacking begins. A suggested technique for removal using chemicals is to cut out a section of actively growing vine and promptly applying a legal herbicide to the bottom half of the cut stem to control re-sprouting. Choose a herbicide only after reading the pesticide label. Some products are labeled for specific sites, and pesticide registrations change over time. Please check with your UF/IFAS Extension service for current recommendations. Hopefully, this article will help you take preventative and proper measures against poison ivy and give you a more care free and informed attitude when partaking in summer activities!
