Biscayne Prickly-ash (Zanthoxylum coriaceum)

A reintroduced Zanthoxylum coriaceum flowering in a City of Miami preserve. Photo Credit: S. Wright

Global Rank: G3 - Vulnerable
Legal Status: N/A
Family: Rutaceae
State: FL
Nature Serve ID: 142953
Lifeform: Shrub, Tree
Date Inducted in National Collection:

Description:

Shrub or small tree to 7 m tall. Stems armed with prickles. Leaves imparipinnate, infrequently paripinnate, (3-) 5-7-foliolate, (6-) 9-14(-18) cm long; central leaf stalk not winged; leaflets leathery, oblong to elliptic, ovate or obovate, with apex acute to acuminate or emarginated, larger leaflets (2-) 3-8(12) x (1-) 2-4(-5) cm, the margin unarmed, entire to barely crenate, rarely crenate, with teeth separated 2-4(-5) mm at the middle of leaflets; pellucid dots not obvious or < 0.2 mm diameter, sparse on blades. Inflorescence 6-9(-14) cm long. Flowers unisexual in dense terminal cymes; sepals three, about 1 mm long, petals 3, stamens 3, follicles 5-6 mm long. Fruit round, in dense clusters, thickly dotted with small glands, 46 mm (Coile 2000, Reynel 1995, Long and Lakela 1971, Buswell 1945).

Where is Biscayne Prickly-ash (Zanthoxylum coriaceum) located in the wild?

Habitat:

COASTAL STRAND, MARITIME HAMMOCK. Coastal hammocks (Long and Lakela 1971, Wunderlin 1998); tropical hammocks, sandy beaches (Coile 2000); near the coast. (Buswell 1945); dry woodlands or scrubs, usually rocky soil or on limestone, commonly in coastal thickets up to 500 m (Reynel 1995); maritime hammocks (Gann et al. 2002), coastal strand and coastal strand/maritime hammock ecotone (Wright pers. obs.).

Distribution:

Florida(Historic)The Keys of Dade and Monroe County (Lakela and Craighead 1965); South Florida and Keys (Long and Lakela 1971); Southeastern US, Florida (Reynel 1995)Not mentioned in Small 1913

States & Provinces:

Biscayne Prickly-ash can be found in Florida

Which CPC Partners conserve Biscayne Prickly-ash (Zanthoxylum coriaceum)?

Fairchild Tropical Botanic Garden

Not Sponsored

Conservation Actions

Assigned 06/09/17

CPC's Plant Sponsorship Program provides long term stewardship of rare plants in our National Collection. We are so grateful for all our donors who have made the Plant Sponsorship Program so successful. We are in the process of acknowledging all our wonderful plant sponsorship donors on our website. This is a work in progress and will be updated regularly.

Conservation Actions

Tina Stanley

05/11/2023

According to a March 2023 extract of the Florida Plant Rescue Database, Fairchild Tropical Botanic Garden holds 4 accessions of Zanthoxylum coriaceum totalling approximately 12439 seeds representing 11 maternal lines.

Center for Plant Conservation

11/26/2021

Center for Plant Conservation

11/26/2021

In September 1998, Miami-Dade County Department of Environmental Resource Management and Fairchild collaborated to augment Zanthoxylum coriaceum at Site 23. The outplanting design consisted of 3 individuals planted into clusters, each with two males and one female. In total 30 trees were planted in two separate areas of Site 23: southern (21 plants) and northern (9 plants). We tagged new seedlings, and documented survival and growth.
By March 2004, 19 of 21 southern site trees survived and appeared in good condition. Forty seedlings are near 4 female trees. In total we documented 40 seedlings (<2cm tall) of which 30 were underneath one female (#26). Of the original 9 “northern” site trees 6 survived. There is only one female left from this section and we observed no seedlings under this tree. By March 2005, 19 southern site trees survive in good condition and 14 of the plants are flowering. Even though some seedlings died since the 2004 survey, we saw 71 seedlings (69 from female #26). Six plants survived at the “northern” site. We observed no seedlings underneath these plants. By March 2006, all plants are still alive from the last census. Of the 69 seedlings that we observed last year under plant #26, only 17 remain alive (25%). Mortality may be due to heavy leaf duff and encroaching Chrysobalanus icaco (coco-plum). Under plant #26, we saw 9 new seedlings and 1 new seedling underneath # 29. By May 2007, all plants but one survived from the 2006 census; 1 female plant may have been lost to an arson fire. Of the 27 seedlings that we documented last year only 16 remain alive. We observed 11 new seedlings originating from four female trees. By May 2008, all plants are still alive from the 2007 census. The female tree burned in last year’s arson fire died. Of the 28 seedlings that we documented last year, 23 survived. We saw 86 new seedlings underneath eight female trees. After ten years, 80% of transplants have survived (24 of 30 alive). Although it took 6 years to record our first seedling, female trees have produced 162 seedlings in the past 4 annual surveys. We are encouraged by the success of this introduction. The planting design may have increased pollinator visits and benefited pollen transfer and fertilization. It is still too early to determine if the introduction is self-sustainable, of the documented 92 seedlings in 4 years, 37 have survived. We will continue to monitor annually the survival of transplants and seedlings.

Center for Plant Conservation

11/26/2021

Zanthoxylum coriaceum (Biscayne prickly ash) is a state endangered tree. Its primary habitat is maritime hardwood hammock, which is vulnerable to urbanization, though it also occurs in coastal strand habitat. Due to habitat fragmentation and development along South Florida’s coast, suitable coastal hammock habitat for Zanthoxylum coriaceum is extremely limited. There are only 72 trees left in the wild and 99% of the trees occur at two sites within 1 mile of each other. The close proximity of the two populations leaves Z. coriaceum vulnerable to possible extinction via one large stochastic event, such as a hurricane. Fairchild recognizes the need to increase population numbers and sizes in the wild and selected Site 162, approximately 11 miles away from the two wild populations, as a suitable reintroduction site. On March 18, 2005, with help from United Way, Hands Over Miami volunteers, we planted 32 trees, installing half the trees in shade and the other half in full sun to test the effect of light on survival, growth, and reproduction and watered every plant with one gallon of water. For the first two months, plants were watered by park staff twice a week, but they no longer receive supplemental watering. Three months after transplant, we saw new growth and flowering. In fact, 8 females are producing fruit. Also we observed larvae of the giant swallowtail butterfly on two of the trees. However, by March 2007, only 10 plants (31%) survived. Factors contributing to the decline of this outplanted population include theft, vandalism damage (two plants were pulled out and left on the ground), possible root rot, and trunk damage cause by landscape maintenance workers. Of the 10 survivors, 6 are females. We observed fruiting from ten other females before they died or disappeared, therefore we will still monitor the area around the dead plants for seedling recruitment. By May 2008, 10 plants (31%) still survived. Fairchild and Park staff met in April 2007 to discuss management options to save the remaining plants. Mulch was placed around the plants to increase their visibility to park staff. Fencing was installed around the Z. coriaceum area in an attempt to better protect the remaining plants. If we were to conduct another planting at this site we would choose areas more protected from landscapers and park patrons. We will continue to monitor the trees for survival, flowering, height, DBH and presence of seedlings twice a year.

Center for Plant Conservation

11/25/2021

Zanthoxylum coriaceum A. Rich (Biscayne prickly ash) is a state endangered small to medium size tree. There are a 66 wild specimens occurring at three South Florida public natural areas. Also there are 136 individuals outplanted at five known sites. Primary habitat is maritime hardwood hammock, which is vulnerable to urbanization. The past and present major threat to Z. coriaceum is habitat destruction. Maritime Hammock, which occurs on the most stable coastal ground, has been and still is attractive to coastal road and building construction. The Florida Department of Environmental Protection maps and monitors both the wild and restored populations on its lands. At Site 6 there are no wild individuals, but in 2001, 18 plants were introduced propagated from seed stock propagated at Fairchild Tropical Botanic Garden collected from the closest population. Survival, height and phenology of introduced plants was monitored quarterly until 2003 and then irregularly. Some individuals are flowering and fruiting. Three plants died in the first quarter following the transplant; storms of 2004 & 2005 probably caused mortality of 3 plants and 5 died due to harsh sandy, dry and exposed conditions.

Center for Plant Conservation

11/25/2021

Center for Plant Conservation

11/25/2021

Zanthoxylum coriaceum A. Rich (Biscayne prickly ash) is a monoecious state endangered small to medium size tree. There are a 66 wild specimens occurring at three South Florida public natural areas. Also there are 136 individuals outplanted at five known sites. Primary habitat is maritime hardwood hammock, which is vulnerable to urbanization. The past and present major threat to Z. coriaceum is habitat destruction. Maritime Hammock, which occurs on the most stable coastal ground, has been and still is attractive to coastal road and building construction. The Florida Department of Environmental Protection maps and monitors both the wild and restored populations on its lands. At Site 6 there are no wild individuals, but 31 plants were introduced using seed stock propagated at Fairchild Tropical Botanic Garden from the closest population. Survival, height and phenology of introduced plants have been documented quarterly since time of outplanting. Monitoring has demonstrated that some individuals are flowering, fruiting and producing seedlings. The seedlings have experienced herbivory from rabbits, occasionally biting off new stems. Two plants have died – one in 1999, the other in 2000. Plants were planted in groups of 5 to 7 with male and female plants. When the health and reproduction of this introduction is compared to others, this clustering of male and female plants seems to be important for seedling recruitment, even though it was not formally tested.

Center for Plant Conservation

11/25/2021

10/09/2020

Demography study at Crandon Park.

Nature Serve Biotics

05/02/2017

Restricted to south Florida and the West Caribbean (Correll and Correll 1982). Rare in Florida (Wunderlin 1998). More information on its status in the West Caribbean is needed.