Dagny Johnson Park: Dr. Wilder Initiates Botanical Inventory

Posted by Nicolette Beard on July 2, 2012 12:05 PM.


The northern half of Key Largo is mostly preserved natural land. That northern half is bisected lengthwise – from north to south – by Route 905. The Dagny Johnson Key Largo Hammock Botanical State Park ("Dagny Johnson Park") comprises most of the land situated east of Rt. 905; the Crocodile Lake National Wildlife Refuge constitutes the majority of land situated west of Rt. 905. 

Some months ago, Dr. Wilder initiated an inventory of the species of vascular plants growing within Dagny Johnson Park. The Park's extensive, comprising 2,421 acres and measuring, approximately, ten miles long. "It will be challenging to complete the plant inventory," notes Dr. Wilder. "I hope that I’ll be able to do so. Completion could require years of work!"

Key Largo Botanical Park History

Dagny Johnson Park contains large areas of tropical hardwood hammock and mangrove vegetation. Present, too, are salt marsh, a very small area of beach vegetation and disturbed land. Parts of the Park are remnants of a Nike missile base dating from the Cold War period, which was functional from 1965 to 1979, approximately. Dagny-Johnson-State-Park-entrance.jpg

The Park was established in 1982 and is named after Anna Dagny Johnson, a local environmentalist – now deceased – who led efforts to save the Park land from development.

Two developers tried successively to develop the area with numerous condominiums and hotels before the Park was established. Fortunately, both attempts failed and both developers declared bankruptcy.

Numerous plant species inhabit Dagny Johnson Park, many of which are localized at specific sites rather than being evenly dispersed within one or more habitats. Such localization of species is an attribute of tropical rain forests situated southward of the United States. Also, many Park species are listed as Threatened or Endangered in Florida.  The large number of listed species reflects the extensive destruction of natural habitat within the Florida Keys, overall.

Numerous Park species do not range northward to our area (Naples, Fla.) and, thus, many such species were initially new to Dr. Wilder and for the herbarium. The remainder of this account will identify specimens of such new species.

New Herbarium Species


Byrsonima lucida (Locustberry). This species is listed as Threatened in Florida.  Its flowers vary from light- to dark pink.

Calyptranthes pallens (Lidflower). The species is listed as Threatened in Florida. There are two Calyptranthes species in the Park; the other species, C. zyzygium, is listed as Endangered.

Cardiospermum corindum (Balloon Vine (or) Heartseed). This vine, with large bladder-like fruits, is common in the Park.

Dodonaea elaeagnoides (Varnishleaf). The species is listed as Endangered in Florida. It is one of two Dodonaea species from Florida.

Duranta erecta (Golden Dewdrops). This is an alien species. It is a shrub with attractive blue flowers.

Guapira discolor (Blolly). This species of Nyctaginaceae (the Four o’clock Family) is common in the Park.

Krugiodendron ferreum (Black Ironwood). At least one species of Krugiodendron (from Belize) has one of the densest woods of all species of  trees: density = 89 lbs/cubic foot (when air-dried); specific gravity = 1.42 (when air-dried). That wood readily sinks, rather than floats, in water.

Manilkara jaimiqui (Wild Dilly). This species is listed as Threatened in Florida. It belongs to the same family as Sapodilla (Manilkara zapota), a species cultivated for its edible (and similar) fruit.

Metopium toxiferum (Poisonwood). This species, a relative of Poison Ivy (Toxicodendron radicans), may cause severe contact dermatitis.

Psychotria ligustrifolia (Bahama Wild Coffee). This species is listed as Endangered in Florida. Two different species of Psychotria grow in our area: P. nervosa and P. salzneri.

Sida ciliaris (Fanpetals). This species is rare in Florida, albeit, it is not a listed species.

Spermacoce tetraquetra (False Buttonweed). This species is also rare in Florida but not listed. Several Spermacoce species grow in our area, but this one doesn’t.

Thrinax morrisii (Thatch Palm). Listed as Endangered in Florida. This species may grow as a tree.

About Dr. George Wilder

Dr. Wilder is the resident Botanist and Herbarium Curator for the Garden. The herbarium contains over 30,000 specimens of dried plant material. This scientific catalog aids researchers in assessing the botanic health of the region and helps to identify and record changes in habitat over time. Dr. Wilder, a former professor of Biology, began collecting in the late 1980s.

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