Species Name: Amorpha herbacea Walter var. crenulata (Rydberg) Isely
Common Name(s): crenulate lead plant, Miami lead plant, bastard indigo
Synonym(s): Amorpha crenulata Rydb.
Family: Fabaceae
Species/taxon description: (Semi)deciduous, sprawling or erect glabrous shrub to 2 m
(6.5 ft) tall. Leaves imparipinnate; Petioles 2-8 mm (0.08-0.3 in) long; leaflets 21-45, elliptic-oblong, 1-2.5 cm (0.4-1.0 in) long, crenulate, apically acute or emarginate, the midvein terminating in a sessile spheroid, glandular knob. Leaflet stalks 1.5-2 mm
(0.06-0.08 in) long. Newer branches often reddish-purple. Raceme(s) clustered from separate leafy branches, 10-20 cm (3.9-7.9 in) long, usually slender, closely or loosely flowered, commonly flexuous and initially with a tapering, rat-tail appearance. Calyx 2-
3.5 mm (0.08-0.14 in) long, puberulent or strigulose, lobes shorter than tube; standard blue-violet or white, 5-6 mm (0.2 in) long. Legume indehiscent, asymetrically erect or falcate, laterally compressed but plump, moderately well exserted from persistent calyx,
4-6 mm (0.2 in) long, glabrate, pericarp hard, glandular-punctate. Seed 1, + 5 mm (0.2 in). (Isley 1990, FAIRCHILD). Isley (1986) first separated this variety from the other forms of A. herbacea by its white flowers and crenulate leaflets. He acknowledged, however, that var. herbacea may have white flowers while var. crenulata may have lavender flowers, and termed A. herbacea var. crenulata a “slightly isolated variant of
A. herbacea.”
Legal Status: Federally endangered, Florida endangered
Biogeographic Value: Native, endemic
Prepared by: Jennifer Possley, Meghan Fellows and Kristie Wendelberger
Conservation of South Florida Endangered and Threatened Flora (ETFLORA) Project,
Research Department, Fairchild Tropical Garden
Last Updated: May 2004 (Wendelberger)
A. Muir

Background and Current Status
Range-wide distribution – past and present
{CONFIDENTIAL}
Population and reproductive biology/life history
Annual/Perennial: Perennial; semi-deciduous, losing some to all of its leaves between
December and February (USFWS undated, Maschinski et al. 2002).
Habit: shrub
Short/Long-Lived: Long-lived
Pollinators: Flowers are visited by: Apis mellifera (a non-native honey bee from the mediteranian), Agapostemon splendens (a metallic green sweat bee), Dianthieium curvatum floridiense (a native leaf cutting solitary bee) and unidentified small flies
(Linares, unpl. data).
Flowering Period: February to August-November (Coile 2000, Maschinski et al.
2002).
Fruiting: Fruits February to August (Coile 2000, Linares pers. comm.), with most of the fruiting occurring in the fall (Wendelberger 2003)
Annual variability in Flowering: Flowers primarily following human disturbance
(USFWS undated). Flowering and seed set may not occur as a result of alteration of ecosystem processes such as fire and drainage (USFWS undated). Flowering occurs every year on a portion of the plants in a population, with or without disturbance, although disturbance does act to synchronize flowering and fruiting in the population
(Maschinski et al. 2002).
Growth Period: Unknown; new growth comes from the root crown or old dead stems
(Maschinski et al., 2002).
Dispersal: None observed (USFWS undated).
Seed Maturation Period: “My hand pollinations in the greenhouse have produced seed in a couple weeks, but then it takes longer to ripen (Linares pers. comm.)”; four to six weeks post dehiscence of petals (Maschinski et al. 2002).
Seed Production: Inflorescences are indeterminate. Not all flowers per inflorescence produce fruit. Fruit may produce 1 seed or rarely 2 seeds (only observed in the ex situ collection, Maschinski et al. 2002). Plants produce significantly more fruit when they are cross-pollinated, though some fruit is produced through self-pollination. The single healthy seed fills the entire carple (Linares unpl. data).
Seed Viability: Seed viability varies with ripeness (Fidelibus and Fellows 2002;
Linares pers. comm.). Removing the fruit coat increases the rate of germination, but does not affect overall germination (Fidelibus and Fellows 2002). Viable seeds are plump and greenish-brown (Fellows 2002; Linares pers. comm.). Wild collected fruit had 29% unhealthy appearing seed versus ex situ -collected fruit had 11% unhealthy appearing seed based on visual inspection (Fellows 2002).
Regularity of Establishment: Seedling recruitment in the wild is rare (Fisher 2000,
USFWS undated) although it is probably more common than originally thought – it is difficult to determine what is a seedling vs. what is a possible clonal propagule
(Maschinski et al. 2002).

Germination Requirements: In a nursery setting, germination of ripe seeds exceeds
50% (Fidelibus and Fellows 2002). Germination occurs on moist filter paper in petri dishes, but also after directly sowing seed in soil maintained with daily watering, during separate trials during summer 2002, in 20% sun (Maschinski et al. 2002). In another study, fresh seeds (with fruit coat intact) from the ex-situ collection germinated readily within the first week of sowing on soil-less media, with total percent germination values ranging from 60% to 84% after 7 weeks (Carrara 2001). Germination requirements in situ are not well understood.
Establishment Requirements: Unknown; When seedlings that were germinated in
20% sun were moved to 70% sun, they had increased growth and improved color, inundating seedlings for 12 days (20% sun) did not kill them (Maschinski et al. 2002).
Population Size: {CONFIDENTIAL}
Annual Variation: None significant
Number and Distribution of Populations: {CONFIDENTIAL}
Habitat description and ecology
Type: PINE ROCKLANDS, MARL PRAIRIE ECOTONE. “ Pine rocklands, especially in the ecotone with marl prairie” (Gann et al. 2002). “Pinelands and hammock edges” (Small 1933). Vacant lots, pine rockland, marl prairie, fire-maintained
(Coile 2000). Pineland-prairie ecotones (DERM 1993).
Physical Features:
Soil: Poorly drained Opalocka sands in pine rocklands or wet prairies with
Opalocka rock outcrop complex soils (USFWS undated). “Can tolerate varying soil depth and litter depth (DERM 1996).
Elevation: two to seven m above sea level (Miami Rock Ridge).
Aspect: unknown
Slope: Extant populations growing on level substrate (Wendelberger per. obs.)
Moisture: Historically, edges of wet prairies in Dade County (DERM 1996).
Light: Open sun to partial shade (USFWS undated). Research by Kernan
(Fisher 2000) showed no relationship between light exposure and fruiting or flowering. However, one population (<10 individuals) under heavy shade has not fruited or flowered for over three years (Maschinski et al. 2002,
Wendelberger, pers. obs.).
Biotic Features:
Community: Sabal palmetto, Rhus copallina var . leucantha, Schizachyrium rhizomatum, Ruellia succulenta, Paspalum monostachyum, Buchnera americana
(USFWS undated) .
Interactions:
Competition: unknown
Mutualism: unknown
Parasitism: unknown
Host: unknown

Mycorrhizae Associations: Arum-type AM fungi present in wild. AMF promotes growth and uptake of P when seedlings grown on natural soil
(Fisher & Jayachandran, 2002).
Other: unknown
Animal use: The silver-spotted skipper ( Epargyreus clarus ) uses A. herbacea var. crenulata for food [further detail not given] (Austin & Smith 1997).
Natural Disturbance:
Fire: Required (USFWS undated)
Hurricane: unknown
Slope Movement: unknown
Small Scale (i.e. Animal Digging): unknown
Temperature: unknown
Protection and management
Summary: Protection of the remaining populations of Amorpha herbacea var. crenulata will be extremely important to ensure species survival through the next decades. Destruction of plants occurs even on protected sites; biologists at Miami-Dade
County and Fairchild need to keep a watchful eye on both the protected and unprotected populations. Proper management of the populations will also be critical—especially at the two populations containing < 10 plants.
Availability of source for outplanting: {CONFIDENTIAL}
Availability of habitat for outplanting: {CONFIDENTIAL}
Threats/limiting factors
Natural:
Herbivory: Leaf herbivory has been observed rarely (Maschinski et al. 2002).
Disease: In situ and ex situ plants are sometimes subject to a witches-broom causing pathogen (Wendelberger, per. obs. and Maschinski et al. 2002).
Predators: unknown
Succession: Pine rocklands subject to fire suppression will succeed into hammocks (Snyder et al. 1980), or weedy lots, which would pose a significant threat to this taxon.
Weed invasion: Invasive plants such as Schinus terebinthifolius Raddi ,
Neyraudia reynaudiana (Kunth) Keng ex Hitchc.
, Bauhina variegata L. pose significant threats (USFWS undated), as do Casuarina sp.
Ardisia elliptica
Thunb., and native Vitis sp. (Maschinski et al. 2002).
Fire: Fire suppression is a significant threat (USFWS undated).
Genetic: unknown
Anthropogenic
On site: Development of unprotected sites is by far the most destructive and most immediate threat. Habitat continues to be lost to urbanization.
Methodologies for habitat management either have not been determined adequately, or are not being carried through at many protected populations. At

one “protected” site, plants along the edge of a nature trail are subject to destruction by contracted construction crews.
Off site: Alterations in drainage systems through canal building (USFWS undated).
Collaborators
Lauren Linares, Florida International University and Florida’s Turnpike
Sonya Thompson, Miami-Dade County, Parks and Recreation, Natural Areas Mgmt.
Conservation measures and actions required
Research history: Fairchild has studied and monitored Amorpha herbacea var. crenulata since the 1990s. Conservation Ecologist Christopher Kernan and Dena
Garvue conducted an experimental outplanting at the Deering estate in 1995. Dena
Garvue and Susan Carrera conducted germination studies in the 1990s, showing 60-
84% germination of fresh seeds and indicating that the taxon may have high storage potential. In addition, individual plants have been mapped on high-resolution aerial photos by Fairchild and The Institute for Regional Conservation. Horticulture experiments have been conducted to assist the plant rescue at a population slated for development. Seed germination, cutting and whole plant translocations have been evaluated for relocation successes. Whole plant translocation and seed germination are recommended (Fellows and Fidelibus unpubl. data). Pollination and reproductive biology have also been the subject of a recent M.S. thesis at Florida International
University (Linares).
Significance/Potential for anthropogenic use: Some interest to native plant enthusiasts.
Recovery objectives and criteria: The federal recovery objective is to prevent extinction, then stabilize. Criteria include a standardized monitoring program to document that populations are large and well distributed enough to prevent extinction, and have sexual and/or vegetative reproduction. Also included, as a criterion, is a management program that protects existing habitat, acquires additional habitat, eliminates degradation, controls exotic plants, and implements prescribed burning.
Management options:
Direct management
Best management practices recommended by the Department of Environmental
Resource Management (1996) include experimental rehydration of current sites to see if seedling establishment is promoted, prescribed burning, and reduction of mowing in the vicinity of plants. Reduction of mowing has been implemented. Unfortunately, this was not followed by prescribed burns, and (native and non-native) invasive species have overtopped many individuals.
Outplantings

Long-term studies of outplantings must be conducted to ensure that they are successful in all aspects of population ecology, including survival, reproduction, growth, and fitness. Appropriate areas to outplant are difficult to identify and it should be given great consideration as to the risk to natural populations of creating a new population or augmenting an existing population.
Next Steps:
Monitor Fall 2002 outplanting.
Continue monitoring wild populations on a biannual basis for mortality, recruitment, and phenology.
References
Austin, D.F. and Smith, E. 1997. Crenulate lead plant. Page 11 In: Pine rockland plant guide. Dade County Department of Environmental Resources Management.
Carrara, S. 2001. Appendix C9: Species specific seed germination methods, storage condition trials, and cultivation notes. In: Fellows, M., J. Possley, and C. Lane. (ed.).
2001. Final Report to the Endangered Plant Advisory Council, Florida Department of
Agriculture and Consumer Services, FDACS Contract # 005619.
Coile, N.C. 2000. Notes on Florida’s endangered and threatened plants. Florida
Department of Agriculture and Consumer Services, Division of Plant Industry, Bureau of Entomology, Nematology and Plant Pathology, Botany section. Contribution No. 38,
3 rd
edition.
DERM (Miami-Dade County Dept. of Environmental Resources Management). 1993.
Final Report: Amorpha crenulata . Task Order 91-1(B). Cooperative Agreement 14-16-
0004-91-951.
DERM (Miami-Dade County Dept. of Environmental Resources Management). 1996?
Endangered plants of dade county’s pine rocklands: habitat characterization for
Amorpha crenulata, Euphorbia deltoidea , and Polygala smallii . Technical Report 96-2.
Fellows, M. 2002. Appendix C2 Amorpha herbacea var. crenulata seed production. In :
Conservation of south Florida endangered and threatened flora. Final report to the
Endangered Plant Advisory Council, Florida Department of Agriculture and Consumer
Services FDACS contract #006466. December 2002. Fairchild Tropical Garden.
Fidelibus, M. and M. Fellows. 2002. Appendix C1: Germination of Amorpha herbacea var. crenulata seed. In: Maschinski, J., M.Q.N. Fellows, J. Possley. (editors). Final
Report to the Endangered Plant Advisory Council, Florida Department of Agriculture and
Consumer Services, FDACS Contract # 006466.

Fisher, J.B. 2000. Demography of pine rockland endangered plant taxa in Miami-Dade
County. Final Report from Fairchild Tropical Garden for Contract 4743, Florida Plant
Conservation Program, Florida Dept. of Agriculture and Consumer Services.
Fisher, J.B. and K. Jayachandran. 2002. Arbuscular mycorrhizal fungi enhance seedling growth in two endangered plant species from South Florida. Int. J. Plant Sci. 163: 559-
566.
Gann, G.D., K.A. Bradley and S.W. Woodmansee. 2002. Rare plants of south Florida: their history, conservation, and restoration. The Institute for Regional Conservation.
Miami, FL. 1056 Pp.
Isley, D. 1986. Notes about Psoralea sensu auct., Amorpha, Baptisia, Sesbania , and
Chamaecrista (Leguminosae) in the southeastern United States. Sida 11(4):429-440.
Isley, D. 1990. Amorpha. Pages 71-76 In: Vascular Flora of the Southeastern United
States. Vol. 3, Part 2: Leguminosae (Fabaceae). The University of North Carolina Press.
Chapel Hill and London.
Maschinski, J., M.Q.N. Fellows, J. Possley. 2002. Conservation of South Florida
Endangered and Threatened Flora. Final Report to the Endangered Plant Advisory
Council, Florida Department of Agriculture and Consumer Services, FDACS Contract #
006466.
Snyder, J. R., A. Herndon, and W. B. Robertson, Jr. 1990. South Florida Rockland.
Pages 203-277 In Ronald L. Myers and John J. Ewel, eds. Ecosystems of Florida.
University of Central Florida Press, Orlando, FL, USA
USFWS, Division of Endangered Species. 2001. Crenulate lead-plant. Species account available online at: http://endangered.fws.gov/i/q/saq2n.html
USFWS. 1988. Recovery plan for five Florida pine rockland plant species. USFWS,
Atlanta, Georgia, 18 pp.
USFWS, South Florida Ecosystem Office. No Date. Endangered is not forever: a recovery plan for the threatened and endangered species of south Florida. Apparently this is a packet from some seminar held by the USFWS, involving the “Multi-species recovery team, pine rockland plants group.”
Wendelberger, K.S. 2003. Amorpha herbacea var. crenulata. In Mmaschinski, J., S.J.
Wright, K. Wendelberger, H. Thornton, and A. Muir (ed.). 2003. Conservation of South
Florida Endangered and Threatened Flora. Final Report to Florida Department of
Agriculture and Consumer Services. Gainesville, Florida. Contract #007182.