Delta Journal
by Bob Thomas

There is a new invasive aquatic plant in town! It is Giant Salvinia, Salvinia molesta, a native of South America that is the first cousin of another invasive that has been clogging our waterways for a number of years, Water-spangle, Salvinia minima.

Giant salvinia was first discovered in the U.S. in South Carolina in 1995, and in Toledo Bend, Louisiana in 1998.

Delta Journal
by Bob Thomas

Have you ever noticed little fuzzy patches on the undersides of oak leaves or what appear to be hard marble-sized cork balls on their stems? People frequently ask about these novelties and are always surprised when told that they are animal in origin, yet produced by the plant.

Delta Journal
by Bob Thomas

Many people consider hackberry trees (Celtis laevigata) to be an unattractive nuisance. Though they may not be one of our most sought after ornamental species, they play an important role in nature.

Hackberries are fast growing, yet short-lived. They may grow to 20 or 30 feet tall in just a few years, but groves begin to die out between 40 and 70 years later. This is not a good trait if one wishes to line the entrance to the family plantation, but it is nice if you have built a new home on a shade-less lot.

One of the summer delights in Louisiana wetland habitats is the wooly rose mallow, Hibiscus lasiocarpus, a member of the Malvaceae.

Wooly rose mallows are easily observed traveling across the LaBranche Wetlands, and along virtually all wet areas in America’s WETLAND (the Louisiana coastal area) where the salinity is not too high.

Delta Journal
by Bob Thomas

One of the most conspicuous forms of vegetation in urban New Orleans is the fern that grows on walls in the Vieux Carré and on tombs in our cemeteries. The most widely used name for this species is Ladder Brake (Pteris vittatus), but it is locally known as Cemetery or Cistern Fern due to its habit of growing in these two moisture retaining areas.

Delta Journal
by Bob Thomas

One of the most spectacular flowering plants in south Louisiana is the Buttonbush, Cephalanthus occidentalis.

Satellite plants, as I call them, have ping pong-size flowers that resemble the space modules. They are white and look a bit like spherical pin cushions due to their many styles (the projecting necks of their female structures), each tipped by a tiny yellow stigma (where the pollen is received).

Delta Journal
by Bob Thomas

One of the most surprising discoveries when we research common local species is the high percentage that are non-native. Those that are difficult to manage and may cause harm to surrounding species are called invasives.

Nature Notes
by Bob Thomas

The tiniest fern in the world is alive and well in New Orleans! The mosquito fern (Azolla caroliniana) is a small floating plant species that may cover the surface of still waters much as does duckweed. The name mosquito fern derives from the belief that mosquitoes cannot lay their eggs in water covered by these diminutive plants.

Nature Notes
by Bob Thomas

People who knock around in the woods are aware of poison ivy, Toxicodendron radicans, but they often have problems correctly identifying the ubiquitous plant. They may know that it has three leaves, but I find they confuse it with everything from Virginia creeper, Parthenocissus quinquefolia, to peppervine, Ampelopsis arborea.

Nature Notes
by Bob Thomas

Some plants just catch your attention. Such is the case with the swollen bladderwort (Utricularia inflata), Family Lentibulariaceae. It is a denizen of clear freshwater wetlands, but can survive in muddy situations if the water dries. Swollen bladderworts are native to the southeastern United States, but have been introduced to other parts of the United States where they are considered to be invasive species.