''Zamia'' is a genus of

cycad Cycads are seed plants that typically have a stout and woody (ligneous) trunk (botany), trunk with a crown (botany), crown of large, hard, stiff, evergreen and (usually) pinnate leaves. The species are dioecious, that is, individual plants o ...

of the family

Zamiaceae The Zamiaceae are a family of cycads that are superficially palm or fern-like. They are divided into two subfamilies with eight genera and about 150 species in the tropical and subtropical regions of Africa, Australia and North and South America. ...

, native to

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

from the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

(in

Georgia Georgia most commonly refers to: * Georgia (country), a country in the South Caucasus * Georgia (U.S. state), a state in the southeastern United States Georgia may also refer to: People and fictional characters * Georgia (name), a list of pe ...

and

Florida Florida ( ; ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders the Gulf of Mexico to the west, Alabama to the northwest, Georgia (U.S. state), Georgia to the north, the Atlantic ...

) throughout the

West Indies The West Indies is an island subregion of the Americas, surrounded by the Atlantic Ocean, North Atlantic Ocean and the Caribbean Sea, which comprises 13 independent island country, island countries and 19 dependent territory, dependencies in thr ...

Central America Central America is a subregion of North America. Its political boundaries are defined as bordering Mexico to the north, Colombia to the southeast, the Caribbean to the east, and the Pacific Ocean to the southwest. Central America is usually ...

, and

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

as far south as

Bolivia Bolivia, officially the Plurinational State of Bolivia, is a landlocked country located in central South America. The country features diverse geography, including vast Amazonian plains, tropical lowlands, mountains, the Gran Chaco Province, w ...

.Kew World Checklist of Selected Plant Families
/ref> The genus is considered to be the most ecologically and morphologically diverse of the cycads, and is estimated to have originated about 68.3 million years ago.

Description

The genus comprises

deciduous In the fields of horticulture and botany, the term deciduous () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed Leaf, leaves, usually in the autumn; to the shedding of petals, aft ...

shrub A shrub or bush is a small to medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from trees by their multiple ...

s with aerial or subterranean circular stems, often superficially resembling

palm Palm most commonly refers to: * Palm of the hand, the central region of the front of the hand * Palm plants, of family Arecaceae ** List of Arecaceae genera **Palm oil * Several other plants known as "palm" Palm or Palms may also refer to: Music ...

s. They produce spirally arranged, pinnate

leaves A leaf (: leaves) is a principal appendage of the stem of a vascular plant, usually borne laterally above ground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, stem, ...

which are pubescent, at least when young, having branched and simple, transparent and coloured hairs. The articulated leaflets lack a midrib, and are broad with subparallel

dichotomous venation A leaf (: leaves) is a principal appendage of the stem of a vascular plant, usually borne laterally above ground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, stem, fl ...

. Lower leaflets are not reduced to spines, though the

petiole Petiole may refer to: *Petiole (botany), the stalk of a leaf, attaching the blade to the stem *Petiole (insect anatomy) In entomology, petiole is the technical term for the narrow waist of some hymenopteran insects, especially ants, bees, and ...

s often have prickles. The emerging leaves of many ''Zamia'' species are striking, some emerging with a reddish or bronze cast ('' Z. roezlii'' being an example). '' Z. picta'' is even more distinctive, being the only truly variegated cycad (having whitish/yellow speckles on the leaves). Like all Zamiaceae, ''Zamia'' plants have "coralloid" (coral-shaped) roots which host nitrogen-fixing cyanobacteria. Stems are in diameter, and when arborial, up to tall. Leaves vary from 2 to up to 15 in number, and have an even number (5 to 60 pairs) of leaflets. petioles (leaf stalks) and

rachis In biology, a rachis (from the [], "backbone, spine") is a main axis or "shaft". In zoology and microbiology In vertebrates, ''rachis'' can refer to the series of articulated vertebrae, which encase the spinal cord. In this case the ''rachi ...

(leaf axis, to which leaflets are attached) may be smooth, or have prickles on the petiole and lower part of the rachis. Leaflets are linear to ovate and may be directly attached to the rachis, or may be on short petiolules. The edges of leaflets may be smooth, or may be toothed partly or around the whole leaflet. The

morphology Morphology, from the Greek and meaning "study of shape", may refer to: Disciplines *Morphology (archaeology), study of the shapes or forms of artifacts *Morphology (astronomy), study of the shape of astronomical objects such as nebulae, galaxies, ...

of leaflets is highly varied between even closely related species of ''Zamia'', and within species and even within populations of a species. Studies have found that the amount of sun a plant is exposed to is responsible for differences in leaflet length, width, surface area, width ratio, shape, and density and thickness of leaflets. There is also significant morphological variation in leaflets between male and female plants in some species.

Reproduction

''Zamia''

sporophyll In botany, a sporophyll is a leaf that bears sporangia. Both microphylls and megaphylls can be sporophylls. In heterosporous plants, sporophylls (whether they are microphylls or megaphylls) bear either megasporangia and thus are called megasp ...

s are born in vertical rows in

cones In geometry, a cone is a three-dimensional figure that tapers smoothly from a flat base (typically a circle) to a point not contained in the base, called the ''apex'' or '' vertex''. A cone is formed by a set of line segments, half-lines, ...

, and the megasporophyll apices are faceted or flattened, not spinose. The fleshy seeds are subglobular to oblong or ellipsoidal, and are red, orange, yellow or rarely white. The endosperm is

haploid Ploidy () is the number of complete sets of chromosomes in a cell (biology), cell, and hence the number of possible alleles for Autosome, autosomal and Pseudoautosomal region, pseudoautosomal genes. Here ''sets of chromosomes'' refers to the num ...

, derived from the female

gametophyte A gametophyte () is one of the two alternating multicellular phases in the life cycles of plants and algae. It is a haploid multicellular organism that develops from a haploid spore that has one set of chromosomes. The gametophyte is the se ...

. The embryo is straight, with two

cotyledon A cotyledon ( ; ; "a cavity, small cup, any cup-shaped hollow", gen. (), ) is a "seed leaf" – a significant part of the embryo within the seed of a plant – and is formally defined as "the embryonic leaf in seed-bearing plants, one or mor ...

s that are usually united at the tips and a very long, spirally twisted suspensor. The sperm of members from the genus are large, as is typical of cycads, and ''Z. roezlii'' is an example; its sperm are approximately 0.4 mm long and can be seen by the unaided eye. It was long believed that ''Zamia'' plants, like all cycads, relied completely on

wind pollination Anemophily or wind pollination is a form of pollination whereby pollen is distributed by wind. Almost all gymnosperms are anemophilous, as are many plants in the order Poales, including grasses, sedges, and rushes. Other common anemophilous plan ...

. In the 1980s it was discovered that at least some ''Zamia'' species were pollinated by beetles of the '' Pharaxonotha'' and '' Rhopalotria'' genera. Further studies have found that pollination by beetles is widespread in ''Zamia'' and other cycads. Seed-dispersal in ''Zamia'' is poorly documented for most species, but there are reports of birds and/or small to medium-sized mammals dispersing the seeds of a few ''Zamia'' species.

Habitats

With one exception, ''Zamia'' species are found only in the

Neotropical realm The Neotropical realm is one of the eight biogeographic realms constituting Earth's land surface. Physically, it includes the tropics, tropical Ecoregion#Terrestrial, terrestrial ecoregions of the Americas and the entire South American temperat ...

in the

Americas The Americas, sometimes collectively called America, are a landmass comprising the totality of North America and South America.''Webster's New World College Dictionary'', 2010 by Wiley Publishing, Inc., Cleveland, Ohio. When viewed as a sing ...

. The exception is '' Z. integrifolia'', which has a range that extends into the

Nearctic realm The Nearctic realm is one of the eight biogeographic realms constituting the Earth's land surface. The Nearctic realm covers most of North America, including Greenland, Central Florida, and the highlands of Mexico. The parts of North America t ...

in northern Florida, and formerly into the southeastern corner of Georgia.

Toxicity

The primary toxin in ''Zamia'' plants is

cycasin Cycasin is a carcinogenic and neurotoxic glucoside found in cycads such as ''Cycas revoluta'' and ''Zamia pumila''. Symptoms of poisoning include vomiting, diarrhea, weakness, seizures, and hepatotoxicity. In metabolic conditions, cycasin is hydrol ...

, a

carcinogenic A carcinogen () is any agent that promotes the development of cancer. Carcinogens can include synthetic chemicals, naturally occurring substances, physical agents such as ionizing and non-ionizing radiation, and Biological agent, biologic agent ...

and

neurotoxic Neurotoxicity is a form of toxicity in which a biological, chemical, or physical agent produces an adverse effect on the structure or function of the central and/or peripheral nervous system. It occurs when exposure to a substance – specifical ...

glucoside. Other

glucoside A glucoside is a glycoside that is chemically derived from glucose. Glucosides are common in plants, but rare in animals. Glucose is produced when a glucoside is hydrolysed by purely chemical means, or decomposed by fermentation or enzymes. Th ...

toxins present include macrozamin ( de) and several neocycasins. BMAA, a neurotoxin that is produced by

cyanobacteria Cyanobacteria ( ) are a group of autotrophic gram-negative bacteria that can obtain biological energy via oxygenic photosynthesis. The name "cyanobacteria" () refers to their bluish green (cyan) color, which forms the basis of cyanobacteri ...

living in roots of the plants, is also present in most ''Zamia'' plants. Many of the ''Zamia'' species are, or have been, gathered to process the stem and/or seeds into starch for use as food or laundry starch, or for use as

traditional medicine Traditional medicine (also known as indigenous medicine or folk medicine) refers to the knowledge, skills, and practices rooted in the cultural beliefs of various societies, especially Indigenous groups, used for maintaining health and treatin ...

. Since almost the entire plant is very toxic, the starch must be grated and repeatedly washed to remove the toxins and make the starch edible. Only the

sarcotesta The sarcotesta is a fleshy seedcoat, a type of testa. Examples of seeds with a sarcotesta are pomegranate, ginkgo ''Ginkgo'' is a genus of non-flowering seed plants, assigned to the gymnosperms. The scientific name is also used as the Eng ...

, the pulpy covering of the seeds, is relatively free of toxins. Consumption of cycads by livestock has resulted in two forms of cycad toxicosis. Hepato-gastrointestinal toxicosis results from damage to the liver and gastrointestinal tracts of affected animals causing depression,

anorexia Anorexia nervosa (AN), often referred to simply as anorexia, is an eating disorder characterized by Calorie restriction, food restriction, body image disturbance, fear of gaining weight, and an overpowering desire to be thin. Individuals wit ...

, and weight loss. Neurologic toxicosis, known as Zamia staggers, is the result of damage to brain, spinal cord, and

dorsal root ganglia A dorsal root ganglion (or spinal ganglion; also known as a posterior root ganglion) is a cluster of neurons (a ganglion) in a dorsal root of a spinal nerve. The cell bodies of sensory neurons known as first-order neurons are located in the dors ...

tissue causing weight loss, swaying of hind quarters, and weakness and other defects in rear limbs.

Herbivory

The presence of toxins protects ''Zamia'' plants from most herbivores, but caterpillars of the genus ''

Eumaeus In Greek mythology, Eumaeus (; Ancient Greek: Εὔμαιος ''Eumaios'' meaning 'searching well') was Odysseus' slave, swineherd, and friend. His father, Ctesius, son of Ormenus, was king of an island called Syra (present-day Syros in the Gree ...

'' are obligate herbivores of cycads, including ''Zamia'' species. ''Eumaeus'' caterpillars have

aposematic Aposematism is the Advertising in biology, advertising by an animal, whether terrestrial or marine, to potential predation, predators that it is not worth attacking or eating. This unprofitability may consist of any defenses which make the pr ...

coloration, being bright red with yellow or white bands, and adults have red elements on their body and wings. The caterpillars sequester and retain the toxins consumed from ''Zamia'' plant tissue, rendering all stages of ''Eumaeus'' distasteful to predators. With few exceptions, ''Zamia'' species host only one species of ''Eumaeus'' caterpillars each. The known host dependencies of ''Eumaeus'' species on ''Zamia'' species include: Species in the Florida/Caribbean clade, or ''Z. pumila'' species complex, are hosts for caterpillars of ''

Eumaeus atala ''Eumaeus atala'', also known as the Atala butterfly or coontie hairstreak, is a small colorful butterfly in the family Lycaenidae. It is found in southeastern Florida (including the Florida Keys) in the United States, Cuba, the Bahamas, and the ...

''. Species in the Fisheri clade, and '' Z. cremnophila'' of the Mega-Mexico A sub-clade, are hosts for caterpillars of '' E. childrenae''. Some species in the ''Z. loddigesii'' species complex of the Mega-Mexico A sub-clade are hosts for caterpillars of '' E. toxea''. Many species in the South American clade west of the Andes are hosts for caterpillars of '' E. godartii''. Several species in the South American clade east of the Andes are hosts for caterpillars of '' E. minyas''. One ''Zamia'' species found east of the Andes, '' Z. poeppigiana'', is host for caterpillars of both ''E. minyas'' and '' E. toxana''. Another ''Zamia'' species east of the Andes, '' Z. amazonum'', also hosts caterpillars of ''E. toxana''. The use of other ''Zamia'' species as hosts for ''Eumaeus'' species had not been established as of 2023. Caterpillars of the moths '' Seirarctia echo'' and '' Anatrachyntis badia'' have also been observed on ''

Zamia integrifolia ''Zamia integrifolia'', also known as coontie, is a small, tough, woody cycad native to the southeastern United States (in Florida and formerly in Georgia (U.S. state), Georgia), the Bahamas, Cuba, the Cayman Islands, and Puerto Rico. Descriptio ...

'', and caterpillars of an unknown species of a

Blastobasidae The Blastobasidae are a family of moths in the superfamily Gelechioidea. Its species can be found almost anywhere in the world, though in some places they are not native but introduced by humans. In some arrangements, these moths are included in ...

moth have been observed on ''

Zamia pumila ''Zamia pumila'', commonly known as guáyiga or guáyara in Spanish, is a small, tough, woody cycad native to the Greater Antilles. ''Z. pumila'' was the first species described for the genus and, therefore, is the type species for the genus ''Za ...

''.

Conservation

Most species of ''Zamia'' are prized as ornamental plants, but are difficult to propagate and slow growing. As a result, ''Zamia'' plants are often over-collected, threatening to wipe out populations or whole species. In order to protect wild populations, scientists working with ''Zamia'' species no longer publish the exact locations of populations.

Karyology

''Zamia'' is the only genus in the cycads that has variation in

karyotype A karyotype is the general appearance of the complete set of chromosomes in the cells of a species or in an individual organism, mainly including their sizes, numbers, and shapes. Karyotyping is the process by which a karyotype is discerned by de ...

s between species, specifically in the

chromosome number Ploidy () is the number of complete sets of chromosomes in a cell, and hence the number of possible alleles for autosomal and pseudoautosomal genes. Here ''sets of chromosomes'' refers to the number of maternal and paternal chromosome copies, ...

Diploid Ploidy () is the number of complete sets of chromosomes in a cell, and hence the number of possible alleles for autosomal and pseudoautosomal genes. Here ''sets of chromosomes'' refers to the number of maternal and paternal chromosome copies, ...

chromosome numbers in ''Zamia'' include 2n=16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, and 28. Some ''Zamia'' species have varying numbers of diploid chromosomes within the species. The odd diploid chromosome numbers occur in species with more than one chromosome number.

Phylogeny

Despite the ancient history of cycads, species diversity in ''Zamia'' is geologically recent. Calonje et al. found a stem age for ''Zamia'' of 68.28

million years ago Million years ago, abbreviated as Mya, Myr (megayear) or Ma (megaannum), is a unit of time equal to (i.e. years), or approximately 31.6 teraseconds. Usage Myr is in common use in fields such as Earth science and cosmology. Myr is also used w ...

(mya), and a

crown A crown is a traditional form of head adornment, or hat, worn by monarchs as a symbol of their power and dignity. A crown is often, by extension, a symbol of the monarch's government or items endorsed by it. The word itself is used, parti ...

age of 9.54 mya.

Geographic groups

As early as the 1930s, authors recognized three

biogeographic Biogeography is the study of the distribution of species and ecosystems in geographic space and through geological time. Organisms and biological communities often vary in a regular fashion along geographic gradients of latitude, elevation, ...

groups in ''Zamia'', Caribbean,

Mesoamerica Mesoamerica is a historical region and cultural area that begins in the southern part of North America and extends to the Pacific coast of Central America, thus comprising the lands of central and southern Mexico, all of Belize, Guatemala, El S ...

n, and Central and South America. In the 21st century, phylogenies of ''Zamia'' based on

molecular phylogenetic Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...

analyses have found stronger correlation with geographic regions than with morphological features. Zonneveld and Lindström (2016) measured

genome A genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding genes, other functional regions of the genome such as ...

size in 71 species of ''Zamia'' and found support for three geographical groupings. Variation in genome size of ''Zamia'' species is fairly small compared to many other genera, with the ratio of largest to smallest just 1.36, but the authors found significant differences in genome sizes between three geographical areas. Species in Mega Mexico, including the northern part of Central America, had the largest average genome size. Species in South America, plus Costa Rica and Panama, had the smallest average genome size, while species in the Caribbean Islands and Florida had an intermediate genome size. Calonje, et al. (2019) analyzed the

DNA Deoxyribonucleic acid (; DNA) is a polymer composed of two polynucleotide chains that coil around each other to form a double helix. The polymer carries genetic instructions for the development, functioning, growth and reproduction of al ...

from 70 species of ''Zamia'', finding support for four geographically distinct

clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...

s (plus a single isolated species). A clade including the species found on the Caribbean islands and in Florida is

sister A sister is a woman or a girl who shares parents or a parent with another individual; a female sibling. The male counterpart is a brother. Although the term typically refers to a familial relationship, it is sometimes used endearingly to ref ...

to the rest of the genus. The species of the Caribbean clade have diverged within the last 1.9 million years. The Mesoamerica clade includes all species found in

(north of

Nicaragua Nicaragua, officially the Republic of Nicaragua, is the geographically largest Sovereign state, country in Central America, comprising . With a population of 7,142,529 as of 2024, it is the third-most populous country in Central America aft ...

), except for the single species '' Z. soconuscensis''. It has a divergence age of 5.79 mya. The Isthmus clade includes species found in southernmost Nicaragua,

Costa Rica Costa Rica, officially the Republic of Costa Rica, is a country in Central America. It borders Nicaragua to the north, the Caribbean Sea to the northeast, Panama to the southeast, and the Pacific Ocean to the southwest, as well as Maritime bo ...

and

Panama Panama, officially the Republic of Panama, is a country in Latin America at the southern end of Central America, bordering South America. It is bordered by Costa Rica to the west, Colombia to the southeast, the Caribbean Sea to the north, and ...

, and has a divergence age of 2.35 mya. The species in South America form another clade, which is sister to the Isthmus clade. It has a divergence age of 2.62 mya. Lindstrom et al. (2024) analyzed

transcriptome The transcriptome is the set of all RNA transcripts, including coding and non-coding, in an individual or a population of cells. The term can also sometimes be used to refer to all RNAs, or just mRNA, depending on the particular experiment. The ...

s from 77 species of ''Zamia'' finding support for seven clades of the genus occupying distinct geographical ranges. Clade I is a strongly monophyletic clade that includes eight of the species of the Caribbean islands and Florida. Clade II (the Fischeri clade), consists of three species found in

Veracruz Veracruz, formally Veracruz de Ignacio de la Llave, officially the Free and Sovereign State of Veracruz de Ignacio de la Llave, is one of the 31 states which, along with Mexico City, comprise the 32 Political divisions of Mexico, Federal Entit ...

Hidalgo Hidalgo may refer to: People * Hidalgo (nobility), members of the Spanish nobility * Hidalgo (surname) Places Mexico :''Most, if not all, named for Miguel Hidalgo y Costilla (1753–1811)'' * Hidalgo (state), in central Mexico * Hidalgo, Coah ...

Querétaro Querétaro, officially the Free and Sovereign State of Querétaro, is one of the Political divisions of Mexico, 32 federal entities of Mexico. It is divided into Municipalities of Querétaro, 18 municipalities. Its capital city is Querétaro Cit ...

San Luis Potosí San Luis Potosí, officially the Free and Sovereign State of San Luis Potosí, is one of the 32 states which compose the Federal Entities of Mexico. It is divided in 59 municipalities and is named after its capital city, San Luis Potosí. It ...

, and

Tamaulipas Tamaulipas, officially the Free and Sovereign State of Tamaulipas, is a state in Mexico; one of the 31 states which, along with Mexico City, comprise the 32 federal entities of Mexico. It is divided into 43 municipalities. It is located in nor ...

states in

Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...

. This clade is a sister to Clade I, with the group of Clade I and Clade II being sister to the rest of the genus. Clade III (Mega Mexico) is divided into the sub-clades III-A and III-B. Clade III-A includes 14 species found in Mexico and northern Central America. Clade III-B consists of seven species found in

Honduras Honduras, officially the Republic of Honduras, is a country in Central America. It is bordered to the west by Guatemala, to the southwest by El Salvador, to the southeast by Nicaragua, to the south by the Pacific Ocean at the Gulf of Fonseca, ...

Guatemala Guatemala, officially the Republic of Guatemala, is a country in Central America. It is bordered to the north and west by Mexico, to the northeast by Belize, to the east by Honduras, and to the southeast by El Salvador. It is hydrologically b ...

, and

Belize Belize is a country on the north-eastern coast of Central America. It is bordered by Mexico to the north, the Caribbean Sea to the east, and Guatemala to the west and south. It also shares a maritime boundary with Honduras to the southeast. P ...

. Clade IV consists of the single species ''Z. soconuscensis'' found in

cloud forest A cloud forest, also called a water forest, primas forest, or tropical montane cloud forest, is a generally tropical or subtropical, evergreen, Montane forest, montane, Tropical and subtropical moist broadleaf forests, moist forest characteri ...

s in

Chiapas Chiapas, officially the Free and Sovereign State of Chiapas, is one of the states that make up the Political divisions of Mexico, 32 federal entities of Mexico. It comprises Municipalities of Chiapas, 124 municipalities and its capital and large ...

state in Mexico. Clade V (the Isthmus clade) includes 15 species found in southern Nicaragua, Costa Rica, and Panama. Clade VI includes 12 species found in southernmost Panama and west of the

Andes The Andes ( ), Andes Mountains or Andean Mountain Range (; ) are the List of longest mountain chains on Earth, longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range ...

Colombia Colombia, officially the Republic of Colombia, is a country primarily located in South America with Insular region of Colombia, insular regions in North America. The Colombian mainland is bordered by the Caribbean Sea to the north, Venezuel ...

and

Ecuador Ecuador, officially the Republic of Ecuador, is a country in northwestern South America, bordered by Colombia on the north, Peru on the east and south, and the Pacific Ocean on the west. It also includes the Galápagos Province which contain ...

. Clade VII consists of four closely related species in northern Columbia (the Manicata clade) and 13 species east of the Andes in

Venezuela Venezuela, officially the Bolivarian Republic of Venezuela, is a country on the northern coast of South America, consisting of a continental landmass and many Federal Dependencies of Venezuela, islands and islets in the Caribbean Sea. It com ...

, Colombia, Ecuador,

Peru Peru, officially the Republic of Peru, is a country in western South America. It is bordered in the north by Ecuador and Colombia, in the east by Brazil, in the southeast by Bolivia, in the south by Chile, and in the south and west by the Pac ...

Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...

, and

Clades and species complexes

Caribbean and Florida Clade (I)

All of the species in the Caribbean plus Florida Clade are also in the ''Zamia pumila'' species complex. The classification of the populations in the

Greater Antilles The Greater Antilles is a grouping of the larger islands in the Caribbean Sea, including Cuba, Hispaniola, Puerto Rico, and Jamaica, together with Navassa Island and the Cayman Islands. Seven island states share the region of the Greater Antille ...

, Bahamas, and Florida has been controversial. In 1980, Eckenwalder included all the ''Zamia'' populations in the Caribbean and Florida in the single species ''Z. pumila'', incorporating 27 previously described species (not all of which were valid or accepted at the time) into the subspecies ''Z. pumila'' subsp. ''pumila'', and five such species from Cuba into the subspecies ''Z. pumila'' subsp. ''pygmaea''. Eckenwalder's classification is no longer generally accepted, and a monophyletic

species complex In biology, a species complex is a group of closely related organisms that are so similar in appearance and other features that the boundaries between them are often unclear. The taxa in the complex may be able to hybridize readily with each oth ...

consisting of eight species is now accepted, including '' Z. pumila'', six other species corresponding to combinations of the species subsumed into Eckenwalder's ''Z. pumila'' subsp. ''pumila'', and '' Z. pygmaea'', consisting of the former species placed by Eckenwalder in ''Z. pumila'' subsp. ''pygmaea''. A 2009 study found support for the species complex in the presence of the same four discrete clusters of DNA repeats in ''Z. integrifolia'', ''Z. portoricensis'', and ''Z. pumila''. The other species in this complex were not examined in that study.

Fischeri Clade (II)

The Fischeri clade consists of three closely related species of ''Zamia'' found near the Gulf coast of central Mexico. The three species, ''Z. fischeri'', ''Z. inermis'', and ''Z. vazquezii'', share various morphological features, including the near or total absence of prickles on leaf stalks. The analysis of DNA by Calonje, et al. found strong support for the Fischeri clade as sister to all of the mainland ''Zamia'' species (i.e., everything except the Caribbean and Florida clade). The analysis of transcriptomes by Lindstrom et al. found strong support for the Fischeri clade as sister to the Caribbean-Florida clade, with the combined Caribbean-Florida and Fischeri clade sister to the rest of ''Zamia''. The Fischeri and Caribbean-Florida clades share several morphological traits, including the lack or near-lack of prickles on leaf stalks and similarities in reproductive characters. The genome sizes of the species in the Fischeri clade are among the smallest in ''Zamia''.

Mega Mexico A Clade (III-A)

The Mega Mexico Clade III-A defined by Lindstrom, et al. in 2024 includes 14 species found in Mexico and northern Central America. The 2019 study of DNA in ''Zamia'' by Calonje, et al. found a clade of 12 species, called the "Mexico Clade", all of which are included in Clade III-A. A study published in 2008 proposed a ''Zamia katzeriana'' species complex, consisting of '' Z. katzeriana'', '' Z. cremnophila'', '' Z. lacandona'', '' Z. purpurea'', and '' Z. splendens''. The 2019 Calonje et al. study found a clade of five species, called the "Purpurea Clade", that included ''Z. cremnophila'', ''Z. lacandona'', ''Z. purpurea'', ''Z. splendens'', and '' Z. grijalvensis'', which shared four species with the ''Zamia katzeriana'' species complex. ''Z. katzeriana'' itself was not included in the 2019 study. ''Z. grijalvensis'' was described in 2012, after the 2008 study that defined the species complex. A genetic study published in 2009 found a basis for a ''Zamia loddigesii'' species complex in the presence of the same four discrete clusters of DNA repeats in '' Z. loddigesii'', '' Z. furfuracea'', ''Z. picta'', '' Z. paucijuga'', ''Z. polymorpha'', '' Z. purpurea'', '' Z. spartea'', '' Z. splendens'', and ''Z. sylvatica''. (After the study was published, ''Z. sylvatica'' was reclassified as a synonym of ''Z. loddigesii'', ''Z. picta'' was reclassified as a synonym of '' Z. variegata'', and ''Z. polymorpha'' was reclassified as a synonym of '' Z. prasina''.) Another 2019 study found a large variation in

within a few ''Zamia'' species, including four in the species complex, ''Z. loddigesii'' (2n=17–18, 24–27), ''Z. paucijuga'' (2n=19, 23–28), ''Z. prasina'' (2n=22–27), and '' Z. lacandona'' (2n=16–18). ''Z. variegata'' has a smaller intraspecific variation in chromosome number (2n=21–22). Two species in the ''Z. loddigesii'' complex, including ''Z. furfuracea'' and ''Z. spartea'', have a chromosome number of 2n=18. '' Z. cremnophila'' and ''Z. purpurea'' have a chromosome number of 2n=16, while ''Z. herrerae'' has one of 2n=24. The 2019 study found a clade of seven species, the "Furfuracea Clade", that included ''Z. furfuracea'', ''Z. herrerae'', ''Z. loddigesii'', ''Z. paucijuga'', ''Z. prasina'', ''Z. spartea'', and ''Z. variegata''. Six of the species in the Furfuracea Clade were also defined in the ''Zamia loddigesii'' species complex, with ''Z. herrerae'' added to the Furfuracea Clade and ''Z. purpurea'' and ''Z. splendens'' removed. '' Z. meermanii'', which is sister to the rest of Clade III-A, but is not in the Mexico Clade in the 2019 study, has not been described as belonging to either the ''Z. katzeriana'' species complex or the ''Z. lodigessii'' species complex.

Mega-Mexico B Clade (III-B)

Clade III-B consists of seven species found in

, and

, including '' Z. decumbens'', '' Z. monticola'', '' Z. onan-reyesii'', '' Z. oreillyi'', '' Z. sandovalii'', '' Z. standleyi'', and '' Z. tuerckheimii''. The 2019 study found a clade of six species, the "Tuerckheimii Clade", that included ''Z. decumbens'', ''Z. onan-reyesii'', ''Z. meermani'', ''Z. sandovalii'', ''Z. standleyi'', and ''Z. tuerckheimii''. Five of the species in the Tuerckheimii Clade were also defined in Clade III-B, with ''Z. meermani'' removed in Clade III-B and ''Z. monticola'' and ''Z. oreillyi'' added.

Isthmus Clade (V)

The Isthmus Clade includes 15 species, all of which occur in

. A few species have ranges that extend into

and, in a couple of cases, southernmost

. One species is also found in northernmost

. The 2024 study based on transcriptomes found three unnamed sub-clades in the Isthmus Clade. One sub-clade, consisting of '' Zamia nana'', '' Zamia acuminata'', '' Zamia fairchildiana'', and '' Zamia pseudomonticola'', was called the "Acuminata Clade" in the 2019 study based on DNA. Three of the deepest nested species in another sub-clade, '' Zamia elegantissima'', '' Zamia stevensonii'', and '' Zamia obliqua'', were placed in the "Obliqua Clade" in the 2019 study. Five of the six species in the third sub-clade have previously been placed in the ''Zamia skinneri'' species complex. ''Z. skinneri'' has been regarded as a highly variable species. ''Z. neurophyllidia'' was described as a new species in 1993, based on a population of what had been regarded as a dwarf form of ''Z. skinneri''. A study published in 2004 proposed that ''Z. neurophyllidia'' and ''Z. skinneri'' were a "hybrid species complex", and noted that ''Z. skinneri'' included several morphologically distinct populations. In 2008, three sub-populations of ''Z. skinneri'' were described as the new species ''Z. hamannii'', ''Z. imperialis'', and ''Z. nesophila''. All five of the species in this complex are found in

Bocas del Toro Province Bocas del Toro (; meaning "Mouths of the Bull") is a Provinces of Panama, province of Panama. Its area is 4,643.9 square kilometers, comprising the mainland and nine main islands. The province consists of the Bocas del Toro Archipelago, Bahía Al ...

in Panama, at least three of the species are endemic to that province, and all of them have plicate leaves, a trait that occurs elsewhere in ''Zamia'' only in ''Z. dressleri'' in Colon and

Guna Yala Guna Yala, also known as Kuna Yala or by its former name San Blas, is a ''Comarca#Panama, comarca indígena'' (indigenous province) in northeast Panama. Guna Yala is home to the indigenous people known as the Guna people, Gunas. Its capital ...

(formerly San Blas) provinces in Panama, and in ''Z. roezlii'' and ''Z. wallisii'' in Colombia. It has been suggested that ''Z. skinneri'' is the central species of the complex, and that the other species have evolved rapidly from ''Z. skinneri'' on the periphery of its range due to geographic or other isolation. The 2019 DNA study places the same five species in a "Skinneri Clade". Both the 2019 DNA study and the 2024 transcriptomes study place '' Z. lindleyi'' as

to the Skinneri Clade.

South America West of the Andes (VI)

The South America West of the Andes Clade includes 12 species, most of which are found in

. A few also occur in

, and one each is found in

and

. The 2019 DNA study defined a "Pacific Clade" consisting of ''Z. gentryi'', ''Z. amplifolia'', ''Z. roezlii'', ''Z. chigua'', and ''Z. lindenii'', which includes all of the species found in Equador and Peru.

South America East of the Andes VII

Manicata clade

In 1996, Caputo et al. described a "Manicata clade" consisting of '' Zamia manicata'', ''Z. cunaria'', ''Z. obliqua'', and ''Z. iepetiensis''. Later

studies have produced a different definition of the clade, with ''Z. manicata'' being the only species included in the new definition. The Manicata clade is a group of closely related species found in northern Colombia. It consists of ''Z. manicata'', ''Z. disodon'', ''Z. melanorrhacis'', ''Z. restrepoi'', ''Z. imbricata'', and ''Z. sinuensis''. ''Z. manicata'' was described in 1876. The other species in the clade have been described more recently, with ''Z. restrepoi'' described in 1990 (as ''Chigua restrepoi'', reclassified as ''Z. restrepoi'' in 2009), ''Z. disodon'' and ''Z. melanorrhacis'' in 2001, and ''Z. imbricata'' and ''Z. sinuensis'' in 2021. The

monophyly In biological cladistics for the classification of organisms, monophyly is the condition of a taxonomic grouping being a clade – that is, a grouping of organisms which meets these criteria: # the grouping contains its own most recent comm ...

of the clade is strongly supported by molecular phylogenetic studies. Calonje, et al. (2019) found ''Z. manicata'', ''Z. disodon'', ''Z. melanorrhacis'', and ''Z. restrepoi'' to form a clade. Lindstrom et al. (2024) found ''Z. manicata'', ''Z. disodon'', ''Z. restrepoi'', and ''Z. sinuensis'' to form a clade. While ''Z. imbricata'' was not included in either analysis, it shares several morphological features with the rest of the clade, including subterranean or semi-subterranean stems, strongly toothed margins on leaflets,

strobili A strobilus (: strobili) is a structure present on many land plant species consisting of sporangia-bearing structures densely aggregated along a stem. Strobili are often called cones, but some botanists restrict the use of the term cone to the woo ...

(cones) on very long stalks, small seeds with very thin

(coats), and very small pollen (male) cones. Leaf morphology varies strongly among the members of the clade.

''Chigua''

'' Chigua'' was described as a new genus with two species in Zamiaceae in 1990, but was reclassified as ''

Zamia restrepoi ''Zamia restrepoi'' is a species of cycad in the family Zamiaceae. As of 2020, according to a preliminary field investigations the sole remaining known subpopulation is alarmingly small, comprising fewer than 100 adult specimens. There is a pote ...

'' in 2009.

Species

The delimitation of species in ''Zamia'' has been problematic. Early taxonomy of the genus was based primarily on leaflet morphology, including leaflet shape, vein number, leaflets per leaf, and

apex The apex is the highest point of something. The word may also refer to: Arts and media Fictional entities * Apex (comics) A-Bomb Abomination Absorbing Man Abraxas Abyss Abyss is the name of two characters appearing in Ameri ...

shape. Based on differences in leaflet morphology, named species proliferated, with 128 species of ''Zamia'' having been named by the 1980s, often based on a single specimen of unknown type site. Many of those proposed species have been moved to other genera or synonymized with accepted ''Zamia'' species. By 1985, moreover, it had been demonstrated that leaflet morphology was influenced by environment and thus not necessarily useful for distinguishing species. It is now recognized that reproductive structures, especially female strobili (cones), are essential to distinguishing species of ''Zamia''. The number of recognized species in ''Zamia'' has almost tripled since 1980. There were approximately 30 species recognized in 1980, 40 in 1988, 58 in 2008, 76 in 2016, and 80 in 2019. As of May 2025, the World List of Cycads lists 89 accepted species of ''Zamia'', the Royal Botanic Gardens, Kew, recognizes 86, and World Flora Online recognizes 90.

Description

Reproduction

Habitats

Toxicity

Herbivory

Conservation

Karyology

Phylogeny

Geographic groups

Clades and species complexes

Caribbean and Florida Clade (I)

Fischeri Clade (II)

Mega Mexico A Clade (III-A)

Mega-Mexico B Clade (III-B)

Isthmus Clade (V)

South America West of the Andes (VI)

South America East of the Andes VII

Manicata clade

''Chigua''

Species

References

Sources

External links