South Florida Field Trip - Part 4

The last stop of our short field trip was the Navy Wells Pineland Preserve near Homestead, Florida, a little ways south of the Robert is Here Fruit Stand and Farm and north of Everglades National Park. Unlike Palm Beach County, which has some kind of public access to most of its county-designated natural areas, most natural areas in Miami-Dade County have no public access and no trespassing signs were posted throughout the perimeter of the preserve. Michael Manna and I, however, had received permission from one of Miami-Dade County's land managers and were able to visit the preserve.

The above sign was posted throughout the perimeter of the Navy Wells Pineland Preserve.

Navy Wells Pineland Preserve has an extremely rich rock pineland flora consisting of numerous grasses, herbaceous wildflowers, vines, and shrubs, many of which are near the northern limits of their natural range and are designated as state-listed threatened or endangered plants. A complete list of the nearly 400 plant species that have been recorded at Navy Wells is available from the Institute for Regional Conservation's web site. Below are a few images that only hint at the rich variety of plants we saw.

Rhynchosia reniformis differs from all other Florida members of its genus in its erect or suberect growth habit; leaves consisting of a single leaflet (instead of three leaflets); and pods conspicuously longer than the calyx.

American beautyberry (Callicarpa americana).

Trema micrantha bore flowers, unripe fruits, and ripe fruits simultaneously.

Euphorbia pinetorum (synonym: Poinsettia pinetorum) has dark green leaves that are often suffused with burgundy. It is a state-listed endangered plant. 

Hieracium megacephalon has small yellow flowerheads less than an inch across but they are very showy when closely examined.

Hypoxis sessilis was easily overlooked unless it was in flower.

Koanophyllon villosum was one of many examples of unusual and rare shrubs growing at Navy Wells Pineland Preserve with tropical affinities and that reach their northern range limits in Miami-Dade County. It is related to the genus Eupatorium and looks very much like a shrubby Eupatorium. The white autumn flowers are very attractive to butterflies and the leaves of some plants, including those at Navy Wells, have a subtle but distinct minty fragrance when crushed.

This image of the non-native Indigofera spicata gives a good indication of the substrate that most plants are growing in at the Navy Wells Pineland Preserve. Note how small the plant is at the end of August in spite of there having been abundant rain during the spring and summer. As a lawn or roadside weed in Palm Beach County, this same plant would have had meter-long stems and abundant flowers and fruits.

Go to Part 1 of a "South Florida Field Trip."
Go to Part 2 of a "South Florida Field Trip."
Go to Part 3 of a "South Florida Field Trip."

Image and text © 2012 Rufino Osorio

South Florida Field Trip - Part 3

This is the third part of a four-part series of blog posts on a short botanical field trip to south Florida.

Our second stop of the field trip was right-of-way road along a canal that had been cut through lime rock. This did not seem like a particular interesting site but it turned out to have a wide variety of grasses, sedges, small herbaceous wildflowers, assorted vines, and various woody plants. And, in a dark, shady spot where a few trees had formed a small grove, Michael Manna found Adiantum tenerum, a native maidenhair fern.

The right-of-way road of a canal was our second stop.

A variety of Euphorbia species were easily seen at this site, including the common and weedy wild poinsettia, Euphorbia cyathophora. Wild poinsettia is very easily grown in any moist to dry lightly shaded to sunny spot but it is remarkably weedy in garden settings and I have had occasions where literally several hundred plants were growing in my garden at one time. They are pretty enough when in full flower but they are annuals and are decidedly less attractive as they slowly decline as they go to seed.

The narrow leaf form of wild poinsettia, Euphorbia cyathophora (synonym: Poinsettia cyathophora).

The true flowers of Euphorbia cyathophora are inconspicuous but they are subtended by modified leaves (bracts) that are brightly colored in various shades of red or orange-red just like the larger, showier Christmas poinsettia.

The broad leaf form of Euphorbia cyathophora is so distinct as to appear to be a different species but every gradation between narrow leaf and broad leaf forms can be found in nature.

I am inordinately fond of sandmat Euphorbia species, which were formerly referred to the segregate genus, Chamaesyce. So I could barely contain my excitement to see that the state-listed endangered plant, Euphorbia conferta was common at this site. It was joined by Euphorbia mendezii, a plant that, at least in south Florida, commonly occurs in disturbed rocky areas. And a third sandmat Euphorbia species (pictured below) was new to me. It was unusual in forming a rounded mat of prostrate stems with a perimeter of ascending flowering stems.

Euphorbia conferta (synonym: Chamaesyce conferta), the plant in the center of the image, is a state-listed endangered species. Here it grew with an assortment of weedy plants and grasses. The tiny yellow daisy in the lower right is Pectis glaucescens.

Euphorbia conferta covered by shallow water that has accumulated in a shallow depression in the lime rock after a rain storm.

An unidentified Euphorbia species.

Completely new to both me and Michael Manna was Tournefortia volubilis, an unusual woody vine in the borage family with tiny yellow-green flowers. It would be interesting to see what pollinates such unusual little flowers. The fruits are pea-sized white berries with two, or sometimes three, conspicuous purplish-black or black spots.

Tournefortia volubilis

In one area, there was a thick growth of Ipomoea hederifolia, an annual or short-lived vine sometimes grown in butterfly or hummingbird gardens for its showy, eye-catching orange or orange-red flowers. But it should not be introduced into small, tidy gardens since it produces numerous, rather unattractive seed capsules and, if conditions are to its liking, it can produce hundreds of self-sown seedlings and can overrun the garden.

Ipomoea hederifolia

We also saw Cissus verticillata, in the grape family (Vitaceae), growing in thickets. It is fairly uncommon in Palm Beach County but was rather common throughout our field trip and, later in the day, we saw it along roadsides as well as climbing fences around avocado groves.

Cissus verticillata

Although the vines were interesting and not something we see every day in Palm Beach County, it was the abundant and varied grasses, sedges, and small wildflowers that most held my attention and the next three images are but a sample of the variety of small herbaceous plants that we found along the canal right-of-way road.

Stachytarpheta jamaicensis, the native blue porterweed, was rather inconspicuous but common throughout the site.

An unidentified member of the hibiscus family (Malvaceae) growing with a few of the many species of grasses found along the canal right-of-way.

Although it has unusual salmon orange or salmon pink flowers, Sida ciliaris was easily overlooked since it rarely exceeded an inch in height. It was but one example of the remarkable assemblage of small, herbaceous plants found at the site.

Go to Part 1 of a "South Florida Field Trip."
Go to Part 2 of a "South Florida Field Trip."
Go to Part 4 of a "South Florida Field Trip."

Image and text © 2012 Rufino Osorio

South Florida Field Trip - Part 2

This is the second part of a four-part series of blog posts on a short botanical field trip to south Florida.

Our first stop of the field trip was a roadside ditch along U.S. Route 27 in southern Broward County, where it runs beside the eastern edge of the Florida everglades.

The Everglades, as seen along U.S. Route 27 in Broward County just north of Miami-Dade County. In the background, one can see killed melaleuca trees (Melaleuca quinquenervia). Without control efforts, much of the Everglades would be a monoculture of melaleuca.

Growing in very large patches in the road median and along the sides of the road was Ruellia ciliatiflora, originally native to South America but now becoming common in south Florida. It is distinct from native Ruellia species in its flowers, which are borne in a stalked inflorescence above the uppermost leaves. In contrast, native south Florida Ruellia species bear their sessile (stalkless) or very short-stalked flowers in the axils of the leaves.

Ruellia ciliatiflora, a native of South America, is spreading in south Florida.

Joining Ruellia ciliatiflora along the roadsides of U.S. Route 27 was Euphorbia heterophylla, a weedy Florida native plant. The Atlas of Florida Vascular Plants does not list it for Palm Beach County but a colony is present on the grounds of the West Palm Beach headquarters of the South Florida Water Management District, where I work, and it has persisted for at least a decade as a weed in the garden of a friend in Lake Worth. Although Florida has been well botanized, it isn't particularly difficult to find new county records and, in the case of Euphorbia heterophylla, finding the new Palm Beach County record was as easy as going to work or visiting a friend's garden.

Euphorbia heterophylla (synonym: Poinsettia heterophylla).

Just a short distance westward from the mowed roadside, in wet depressions that paralleled the west side of U.S. Route 27, there were colonies of the state-listed endangered plant, Lippia stoechadifolia. In places, the colonies extended for thousands of yards and one would scarcely think that it was a particularly rare plant. The genus Lippia closely resembles Phyla but Lippia species have at least some stems that are erect or ascending and become woody with age. In contrast, Phyla has creeping stems, none of which ever become erect and woody.

Lippia  stoechadifolia (synonym: Phyla stoechadifolia) is a state-listed endangered plant recorded only from Broward, Collier, and Miami-Dade counties.

Close-up of the tiny flowers of Lippia stoechadifolia.

Many typical native plants of wet ground were growing with Lippia stoechadifolia but especially notable was Pluchea baccharis (synonym: Pluchea rosea). I had never seen such large, healthy, robust specimens and the dark pink to maroon-pink flowerheads made a pleasing contrast to the whitish upper leaves and bracts of the inflorescences.

Pluchea baccharis (synonym: Pluchea rosea), formed large freely flowering plants at this site.

Go to Part 1 of a "South Florida Field Trip."
Go to Part 3 of a "South Florida Field Trip."
Go to Part 4 of a "South Florida Field Trip."

Images and text © 2013 Rufino Osorio

Euphorbia thymifolia – Thyme-leaf Sandmat

Euphorbia thymifolia (synonym: Chamaesyce thymifolia) is an unassuming little annual native from Mexico to Argentina, the West Indies, and the paleotropics (Africa and Asia). It has been introduced in the Hawaiian islands and is considered by some to have been introduced in Florida, but the Atlas of Florida Vascular Plants lists it as native. I have observed it at three sites in Florida: (1) in pavement cracks in downtown Tampa; (2) near the mouth of a gopher tortoise burrow in a sandhill habitat in Tampa; and (3) in a highly disturbed old field that had originally been sand scrub at Jonathan Dickinson State Park in Martin County.

A young plant growing under very harsh conditions in a tiny crack in the street in front of my house.

As is the case with most annual, weedy spurges formerly in the genus Chamaesyce, it is very easily grown and, once introduced into a garden, you will likely have it forever. Although it can be a weed of potted plants, thus far it has not been a problem in the garden. Certainly, it is nowhere near as aggressive and abundant as the quadrumvirate of weedy spurges in my yard that can sometimes number in the hundreds: Euphorbia graminea, Euphorbia hirta, Euphorbia hypericifolia, and Euphorbia ophthalmica.

Images and text © 2013 Rufino Osorio

A Xeric Garden

A dwarf agave with rosettes less than 12 inches wide toughs it out in pure Florida sand. My guess is that it is one of the many forms of Agave potatorum. The genus Agave is native to the New World from the southern United States to South America but it reaches its greatest diversity in Mexico.

I have been watching the endeavors of a local gardener with keen interest. Apparently having grown weary of tending a lawn, this gardener removed all grass from a small front yard and is growing tough desert plants. Although markedly different from the typical pseudo-tropical south Florida garden, it shares with such gardens the presence of plants from far-flung regions of the world and a lack of any native plants.

Euphorbia tirucalli is native to Madagascar and is characterized by a highly toxic and caustic sap. It has also been linked with Burkitt's lymphoma, a typically rare cancer that tends to be associated with regions where Euphorbia tirucalli is extensively used as a hedge plant. The pictured plant is a cultivar with brightly colored new growth called 'Sticks on Fire.'

An Opuntia species with a growth habit similar to the native semaphore cactus (Opuntia corallicola); however, the native semaphore cactus is markedly spiny and tends to have pads of a lighter green color.

The so-called Madagascar palm is not a palm at all. It is Pachypodium lamerei, a spiny-stemmed succulent from Madagascar in the oleander family (Apocynaceae). It should be handled with care since the spines are extremely sharp and can cause severe injuries or infections if they happen to impale the knuckles or joints of the fingers.

This aloe is very similar to Aloe arborescens from Africa; however, the rosettes are much smaller than that species. I am guessing that perhaps it is a small-growing hybrid of Aloe arborescens.

Images and text © 2012 Rufino Osorio