Introduction to the Acanthaceae Family

When you learn to identify the Acanthaceae family, it helps to know that it is part of the Lamiales order of core eudicots and is closely related to the Lamiaceae, or mint family, with which it shares several characteristics. The Acanthaceae are widespread in tropical and subtropical regions, but the USA has quite a few, and they can even be found in temperate Canada.

What I love most about this family is their unique, often beautiful, and conspicuous bracts that surround their lovely flowers. Unsurprisingly, several species are used ornamentally, but others are also used medicinally. In the field, if you are injured, crush the leaves of most Acanthaceae and apply them directly to the wound to help healing. 

Beginner’s Guide to the Bear’s Breeches Family

If you’re new to plant morphology, this guide is a perfect beginner’s description to learn about the Bear’s Breeches (Acanthaceae) family, with no need to know any scientific jargon. Below is additional information on uses and morphology, as well as pictures to help identify family members and individual species found in North America.

But for researchers or those wanting to learn a more in-depth version, check out the Scientific Botanical Description below the images in addition to genus-level distribution data.

Leaves and Stems of the Bear’s Breeches Family

Most members are tropical herbs, shrubs, or climbing vines. Leaves are mostly simple (not compound) and arranged in opposite pairs along the stem, which often has swollen joints (nodes). Many species have mineral crystals (cystoliths) visible in their leaves and are covered with small hairs.

Flowers of the Bear’s Breeches Family

Flowers may be small or large and showy and are typically irregular in shape, often forming funnel-shaped flowers or two-lipped flowers where the petals are joined at the base into a tube. Flowers are almost always surrounded by large, showy, leaf-like structures called bracts, which are very characteristic of most members of the family.

Reproductive Features of the Bear’s Breeches Family

Most flowers contain both male and female parts (hermaphrodite or bisexual), with 2-4 stamens (male parts) attached inside the petal tube, often accompanied by smaller, sterile “fake stamens” (staminodes). The superior ovary (attached above the point of petal attachment) has a long, thread-like tube (style) on top to catch pollen and a nectary ring (hypogynous disk) at the base to attract pollinators.

Fruits of the Bear’s Breeches Family

Fruits are almost always a dry, 2-chambered capsule that usually splits explosively when dry to scatter its seeds via small, hooked stalks (retinacula) attached to the seeds, aiding in their ejection from the fruit. However, in some taxa they are fleshy drupes (like a cherry) or leathery capsules that don’t split explosively.

Morphology of Acanthaceae in North America

Some Acanthaceae Species Found in North America

Acanthoideae Subfamily

Acanthus mollis—Bear’s Breeches

A clump-forming perennial herb with tuberous roots, a basal rosette of deeply lobed leaves, and tall spikes of pinkish or purplish flowers. Native to the Mediterranean, often cultivated in North America for its leaves and flowers.

Carlowrightia arizonica – Arizona Wrightwort

Heavily branched subshrubs are 10–30 cm tall, or sometimes taller. Leaves are simple, opposite, and variable in size and shape but approximately lanceolate. Flowers are narrowly triangular with 2 lateral petal lobes, 2 upper lobes fused with a yellow spot and purple streaks, and a keeled bottom lobe. Native to Texas, Arizona, California, and northern Mexico.

Dicliptera resupinata—Arizona Foldwing

An erect herb, up to 60 cm tall, with heavily branching, pubescent stems; the leaves are lanceolate, 2 – 6 cm long. Flowers are two-lipped, light purple with small dark purple lines near the center, and surrounded by two heart-shaped bracts. Native to southern AZ and NM, United States, and northwestern Mexico.

Justicia pilosella—Hairy Tubetongue

Herbaceous perennial to 30 cm tall with opposite leaves that may be pubescent or glabrous, but with ciliate margins and zygomorphic sessile flowers, with a long, white, pubescent tubular corolla with 4 pink or purple lobes, 3 of which bend outwards strongly. Narrowly endemic to southern TX and southern NM in the USA, plus arid northeastern Mexico.

Ruellia blechum—Green Shrimp Plant

Short herbaceous perennial that is erect or clambering, with opposite ovate leaves and a conspicuously pyramidal-shaped inflorescence, often with pilose pyramidal bracts and a conspicuous spike with pyramidal bracts. Native to Mexico, Central & South America. This one was from Paco’s Nature Reserve, Sinaloa, Mexico.

Ruellia caroliniensis – Carolina Wild Petunia

Unbranched herbaceous perennial to 1 m with opposite, oval leaves and sessile axillary clusters of 2 – 4 flowers with usually only 1 – 2 open at a time; leaves and flowers are crowded together at the top of the plant. Flowers are light purple to pinkish with a slender corolla tube and 5 petaloid lobes and long, pointed calyx lobes. Native throughout the eastern USA.

Ruellia humilis – Wild Petunia

Perennial herb up to 60 cm tall, with tubular, bell-shaped flowers with a long, skinny white tube and five shallow, rounded lavender to lilac-colored petals, singly or in clusters in upper axils, not crowded at the top of the plant. Native to the eastern and central USA.

Ruellia nudiflora – Violet Wild Petunia

An erect perennial, 30 – 60 cm tall, with few branches and opposite gray-green leaves 5 – 12 cm long, with wavy-toothed margins on short petioles. Terminal inflorescence of lavender to purple trumpet-shaped flowers (bractless, hence “nudiflora”) with inserted stamens. Native to the southern USA (AZ east to AL), Mexico, and Central America.

Ruellia strepens – Smooth Wild Petunia

An herbaceous perennial plant 0.5 – 1 m tall, sometimes branching, with hairless or sparsely hairy stems; opposite leaves up to 13 cm long, lanceolate to ovate, with smooth or slightly undulate margins and mostly hairless surfaces. Nearly sessile flowers in clusters of 1 – 3 in upper axils. Native to the south-central & southeast USA.

Tetramerium nervosum – Hairy Fournwort

Subshrub to 30 cm tall with opposite lanceolate leaves. Flowers in conspicuous pilose leafy bracts on hairy, 4-sided spike inflorescences; tubular with an upper lobe with a violet patch and a yellow base, 2 side lobes, and a keel-like lower lobe. Native to AZ and TX, USA, and south through Mexico and Central America to Venezuela.

Nelsonioideae Subfamily

Elytraria imbricata – Purple Scaly Stem

Weedy subshrub with linear leaves crowded at the top of the plant that may be basal and stemless or up to 60 cm tall. Inflorescences with very appressed bracts, blue flowers. Native from the southern USA to northern Argentina, mostly in dry tropical forests.

Thunbergioideae Subfamily

Thunbergia grandiflora – Blue Trumpet Vine

A twining evergreen vine 2 – 2.5 m long, with large, heart-shaped, bright green leaves and large, showy, lavender-blue, trumpet-shaped flowers up to 7 cm across with a yellow or white throat. Native throughout Southeast Asia. Often cultivated as an annual in North America.

Uses of the Acanthaceae 

The leaves of many Acanthaceae are used externally for wounds, and recent research has shown that the family has antifungal, anti-inflammatory, antipyretic, antioxidant, insecticidal, immunomodulatory, anti-platelet aggregation, and antiviral potential. More research is currently underway.

Notable ornamentals include bear’s-breech (Acanthus mollis), clock vine (Thunbergia), shrimp plant (Justicia brandegeana), caricature plant (Graptophyllum pictum), and numerous others.

Ecosystem and Wildlife Values of Acanthaceae 

The leaves of many Acanthaceae serve as primary larval hosts for several nymphalid butterflies, including the Common Buckeye, checkerspots, and more.

Many members have specialized pollination mechanisms that provide nectar for birds, bats, and specialist bees.

The mangrove genus Avicennia (Avicennioideae) acts as a foundational ecosystem engineer in intertidal marine and estuarine environments, ranking among the most carbon-dense ecosystems for carbon sequestration.

Taxonomy of Acanthaceae

The Acanthaceae family has 4605 species in 191 genera. It is part of the Lamiales order of the Core Eudicots. There are currently four recognized subfamilies of the Acanthaceae. Many more genera used to be present but have been submerged into Justicia, Ruellia, and others based on modern phylogenetics.

Acanthoideae Subfamily

The Acanthoideae are the largest subfamily by far, mostly made of herbs or sometimes shrubs, vines, or rarely trees. The presence of vascular bundles arranged in a circle in the petiole and the presence of cystoliths are nearly universal. The corolla often has the abaxial lobe outside the others when in bud, but it can also show contorted or imbricate variations. Anthers are sagittate, or the thecae are nonopposite and displaced, sometimes with one theca reduced, and the stigma is dry and typically bifid. Capsules are obovoid and almost universally explosive via retinacula with flattened seeds. 

Genera of the Acanthoideae Subfamily

Acanthopale (12), Acanthopsis (20), Acanthus (30), Afrofittonia (1), Ambongia (1), Ancistranthus (1), Andrographis (27), Angkalanthus (1), Anisacanthus (11), Anisotes (29), Aphanosperma (1), Aphelandra (212), Ascotheca (1), Asystasia (61), Ballochia (3), Barleria (307), Barleriola (4), Blepharis (128), Borneacanthus (6), Boutonia (1), Brachystephanus (21), Bravaisia (3), Brillantaisia (14), Brunoniella (6), Calacanthus (1), Calycacanthus (2), Camarotea (1), Carlowrightia (27), Celerina (1), Cephalacanthus (1), Chalarothyrsus (1), Chamaeranthemum (4), Champluviera (2), Chileranthemum (3), Chlamydacanthus (3), Chlamydocardia (2), Chroesthes (4), Clinacanthus (3), Clistax (3), Codonacanthus (3), Cosmianthemum (14), Crabbea (14), Crossandra (54), Crossandrella (3), Cyclacanthus (2), Cyphacanthus (1), Dasytropis (1), Dianthera (41 when not inc. in Justicia), Dichazothece (1), Dicladanthera (2), Dicliptera (242), Dinteracanthus (5), Dischistocalyx (12), Duosperma (26), Dyschoriste (98), Ecbolium (22), Echinacanthus (4), Eranthemum (22), Eremomastax (1), Filetia (9), Fittonia (2), Forcipella (6), Glossochilus (1), Graphandra (1), Graptophyllum (15), Gymnostachyum (53), Gypsacanthus (1), Haplanthodes (4), Harpochilus (3), Hemigraphis (31), Henrya (3), Herpetacanthus (21), Heteradelphia (2), Holographis (18), Hoverdenia (1), Hulemacanthus (2), Hygrophila (76), Hypoestes (139), Isoglossa (83), Isotheca (1), Jadunia (2), Justicia (959), Kenyacanthus (1), Kosmosiphon (1), Kudoacanthus (1), Lankesteria (7), Lasiocladus (4), Leandriella (2), Lepidagathis (157), Leptosiphonium (10), Leptostachya (1), Linariantha (1), Louteridium (11), Mackaya (5), Marcania (1), Megalochlamys (10), Megaskepasma (1), Melittacanthus (1), Mellera (7), Metarungia (1), Mexacanthus (1), Mimulopsis (20), Mirandea (6), Monothecium (3), Morsacanthus (1), Neriacanthus (1), Neuracanthus (32), Odontonema (32), Oplonia (21), Pachystachys (18), Pararuellia (11), Pericalypta (1), Petalidium (46), Phaulopsis (21), Phialacanthus (5), Phlogacanthus (42), Physacanthus (3), Podorungia (5), Poikilacanthus (13), Populina (2), Pranceacanthus (1), Pseuderanthemum (134), Pseudodicliptera (4), Psilanthele (1), Ptyssiglottis (38), Pulchranthus (4), Rhinacanthus (24), Ritonia (3), Ruellia (379), Ruelliopsis (1), Rungia (87), Ruspolia (4), Ruttya (6), Salpixantha (1), Samuelssonia (1), Sanchezia (45), Sapphoa (2), Satanocrater (4), Schaueria (15), Sclerochiton (18), Sebastiano-schaueria (1), Spathacanthus (4), Sphacanthus (2), Sphinctacanthus (2), Stenandriopsis (20), Stenandrium (50), Stenostephanus (95), Stenothyrsus (1), Streblacanthus (3), Streptosiphon (1), Strobilanthes (466), Strobilanthopsis (1), Suessenguthia (8), Tetramerium (31), Thysanostigma (2), Trichanthera (2), Trichocalyx (2), Trichosanchezia (1),Vindasia (1), Whitfieldia (13), Xantheranthemum (1), Xerothamnella (2), Yeatesia (3), and Zygoruellia (1).

Avicennioideae Subfamily

The Avicennioideae are trees with pneumatophores, sometimes stilt roots. The leaf lamina is thick with salt glands on both sides, club-shaped hairs, and colleters. Flowers are 4(-6) merous and quincuncial, with nectar glands on the inside of the tube. Stamens are equal and alternate with the corolla, and the stigma has two blunt lobes. The fruit is a fleshy or leathery capsule with 2 valves but is functionally single-seeded and exhibits cryptovivipary. 

Genera of the Avicennioideae Subfamily

Avicennia (8).

Nelsonioideae Subfamily

The Nelsonioideae are mostly herbs with glandular hairs, though some are subshrubs or shrubs. The inflorescence may be terminal or axillary, bracts are spiral, and bracteoles are sometimes absent. The corolla exhibits descending cochleate aestivation with the adaxial lobes outside the others. There are 2 stamens, each with variable anthers, and the thecae may or may not be separate, or there may be 4 didynamous stamens, and the stigma is broadly lobed. An important feature is the lack of retinacula attached to the seeds and the absence of cystoliths, which separates them from most other members of the family. 

Genera of the Nelsonioideae Subfamily

Anisosepalum (3), Aymoreana (1), Elytraria (22), Nelsonia (3), Saintpauliopsis (1), and Staurogyne (155).

Thunbergioideae Subfamily

The Thunbergioideae subfamily is mostly twining vines, but erect shrubs do occur. Petiole bundles are arcuate or annular with wing bundles. Leaf lamina venation is strongly curved, and like the Nelsonioideae, they lack cystoliths. The inflorescence consists of axillary or fasciculate flowers that lack bracts and have a strongly reduced calyx, but the bracteoles are very large, replacing the protective function of the calyx and may or may not be connate. The stigma is small, wet, sub-bilobed to trumpet-shaped, and has broad and often unequal papillate lobes. Unique to the family, some members produce fleshy, indehiscent drupes.

Genera of the Thunbergioideae Subfamily

Anomacanthus (1), Mendoncia (90), Meyenia (1), Pseudocalyx (6), and Thunbergia (150+).

Key Differences From Similar Families

The Acanthaceae are most often confused with other families in the Lamiales order because they share opposite leaves and zygomorphic flowers.

However, the Lamiaceae can be differentiated by their aromatic essential oil glands and their absence of cystoliths and retinacula as well as their deeply 4-lobed ovary with a gynobasic style rather than the unlobed ovary with a terminal style in Acanthaceae.

The Verbenaceae are similar but can be differentiated by their lack of cystoliths and bracteoles and their fruits, which are fleshy drupes instead of the usually explosive capsules seen in the Acanthaceae.

Scientific Botanical Description of the Acanthaceae

This section is for researchers or others wanting a more in-depth scientific description to learn how to identify the Acanthaceae family.

Habit & Leaf Form of the Acanthaceae

The Acanthaceae are mostly tropical annual or perennial herbs (with or without a basal aggregation of leaves), shrubs, or stem twiners, root climbers, or scrambling vines, although some epiphytes or, rarely, small to medium leptocaul trees (with pneumatophores and sometimes stilt roots in Avicennia) are also seen. Branches are terete to angular in cross-section. Plants may be hydrophytic, helophytic (including a few mangroves), mesophytic (many from damp tropical forests), or xerophytic.

Leaves are simple and usually well developed but sometimes are much reduced, or occasionally plants are aphyllous switch-plants. Leaves may sometimes be heterophyllous and are often swollen at the nodes but lack stipules.

Leaves are arranged opposite, distichous, or decussate, and are rarely whorled. ), The lamina may or may not be gland-dotted; it is dissected or entire, pinnately veined, and cross-venulate. Lamina margins are entire, crenate, serrate, or dentate and may be flat, revolute, or involute. The leaf lamina is dorsiventral (sometimes incomplete) or bifacial (isobilateral in several genera), with or without epidermal salt glands, and the abaxial surface may be papillose.

Stomata are mostly diacytic (confined to the abaxial surface), but in Lepidagathis, they are paracytic and are variable in some basal taxa.

Diverse hairs are present, including eglandular, unicellular, uniseriate, glandular (may always be glandular in Nelsonioideae), and multicellular branched or simple. Cystoliths are very often present as streaks in the lamina.

Flowers of the Acanthaceae

Plants are almost always hermaphrodites, but dioecous and gynodioecius taxa do occur. Pollination is entomophilous, ornithophilous, or chiropterophilous and may be conspicuously specialized.

Flowers are solitary or, more often, aggregated in terminal or axillary racemes, cymes, thyrses, or often in dichasial cymes that are often condensed in the leaf axils; sometimes they are pseudanthial.

Flowers are subtended by bracts and paired bracteoles, which are often large, showy, or modified. In Thunbergioideae, bracts are absent or highly reduced, but paired bracteoles are still present. In Nelsonioideae, bracts are present, but bracteoles are sometimes absent.

Flowers are usually more or less zygomorphic, sometimes actinomorphic. They are tetracyclic, 4- or 5-merous, with a distinct calyx and corolla (2 whorls), and are predominantly zygomorphic, but sometimes actinomorphic or nearly so. A nectariferous hypogynous disk is present around the base of the ovary.

The calyx is 1-whorled and connate, typically 4-5 lobed via fusion of the anterior or posterior lobes. It is valvate or imbricate in bud, but in Thunbergia it is reduced to a truncate rim or multidentate ring.

The corolla is 1-whorled and connate, at least basally, with 4-5 lobes, ranging from tubular/infundibuliform to distinctly bilabiate or apparently 1-lipped when the upper lip is suppressed. Aestivation varies and is often diagnostic at the subfamily level and may be ascending cochlear (Nelsonioideae), descending cochlear (Acanthoideae), quincuncial (Avicennioideae), or contorted (Thunbergioideae and Acanthoideae).  

Androecium of the Acanthaceae

The androecium has 2 or 4 (rarely 5) members that are epipetalous and alternipetalous, adnate, and usually inserted on the corolla tube and, when 4, are usually didynamous. Members may be equal or unequal, free of one another, or coherent and one whorled, exerted, or deeply included.

The androecium may consist entirely of fertile stamens or may include staminodes in the same series as the fertile stamens; stamens are often hairy, bearded, appendaged, or spurred.

Anthers may be separate from one another or connivent; they are dorsifixed or basifixed, dehiscing predominantly via longitudinal slits or rarely apical pores. They are typically tetrasporangiate but become monothecous or functionally unilocular through the reduction or abortion of one theca in some taxa.

Gynoecium of the Acanthaceae

The gynoecium is 2-carpelled, syncarpous, and superior, forming a sessile, 2-locular ovary (or rarely imperfectly 4-locular with false septa).

There is a single, slender, terminal, filiform style that arises, attenuated, from the ovary. longer than the ovary. The stigma is predominantly bifid with unequal lobes of the dry, non-papillate type, although they are wet and papillate with broad, often trumpet-shaped lobes in Thunbergioideae.

Placentation of the ovules is axile but may be apical or pendulous in Avicennia. Ovule numbers vary widely by lineage, with numerous (10-50+) per locule in Nelsonioideae and 2 to few, rarely up to 12, in the other subfamilies. Ovules are unitegmic, tenuinucellate, and anatropous to amphitropous/campylotropous. In core Acanthoideae, the funicle develops into a hardened, ossified hook (retinaculum).

Fruit of the Acanthaceae

The fruit of the Acanthaceae is usually a non-fleshy, 2-chambered loculicidal capsule that dehisces somewhat explosively via retinacula. In some species, fleshy drupes (some Thunbergioideae) or occasionally a compressed, leathery 2-valved capsule (Avicennioideae) are present.

Seeds are non-endospermic, may be conspicuously adorned with hairs, scales, or tubercules, and may contain starch.

Global Distribution of Acanthaceae

The Acanthanceae are mostly tropical and subtropical species, with a few temperate outliers. They are native and widespread throughout the tropical and subtropical latitudes in Africa, Australia, Indonesia, and the Americas. 

Distribution of Acanthaceae in the Americas

Canadian Acanthaceae Genera

Acanthoideae in Canada

Dianthera 1 sp. native to ON and QC (s/t included in Justicia); Justicia 1 sp. native in QC and ON. 

USA Acanthaceae Genera

Acanthoideae in the USA

Acanthus 1 sp. intro to CA; Andrographis 1 sp. intro to VA; Anisacanthus 4 spp. native to AZ, NM, and TX; Asystasia 1 sp. intro to FL and AL; Barleria 2 spp. intro to FL; Carlowrightia 8 spp. native to CA, AZ, NM, and TX, and intro in FL; Dianthera 9 spp. including 8 native and 1 intro AZ, KS S to TX, and all E to NJ and S to FL from there plus IA, MI, NY, and VT (s/t included in Justicia); Dicliptera 4 spp. native to S half of USA from AZ E to NC and all S plus KS, MO, IL, IN, KY, and VA; Dyschoriste 6 spp. native to NM, AZ, TX, LA, OK, FL, AL, GA, and SC; Eranthemum 1 sp. intro to FL; Graptophyllum 1 sp. intro to FL; Hemigraphis 2 spp. intro to LA and FL; Henrya 1 sp. native to AZ; Hygrophila 6 spp. native and intro to TX, LA, AL, MS, GA, FL, and VA; Hypoestes 1 sp. intro to HI; Justicia 19 spp. native and intro in most of S half USA CA E to NJ and all S exc NV, UT, CO and inc IA, WI, MI, NY, and VT; Megaskepasma monospecific, formerly N SAM endemic, introduced in HI; Odontonema 2 spp. intro to AL and FL; Pseuderanthemum 1 sp. intro to FL and SC; Ruellia 22 spp. native in most of E half USA from ND S to TX and all E exc. ND, SD, CT, RI, MA, VT, NH, ME, and including AZ and NM, but intro in AK and NY; Sanchezia 1 former neoendemic sp. intro to HI; Stenandrium 2 spp. native in NM, TX, FL, and GA; Strobilanthes 1 sp. intro LA and FL; Tetramerium 1 sub & tropical Americas endemic sp. native to NM, AZ, and TX; Yeatesia 2 SE NAM endemic spp. native to TX, LA, AL, MS, FL, and GA.

Avicennioideae in the USA

Avicennia 2 of 8 pantropical spp. native to TX, MS, AL, GA, LA, and FL and introduced to CA.

Nelsonioideae in the USA

Elytraria 3 spp. native to NM, AZ, TX, FL, GA, and SC, including 1 narrow endemic to GA, FL, and SC; Nelsonia 1 sp. intro to FL.

Thunbergioideae in the USA

Thunbergia 5 spp. intro in TX, FL, and HI. 

Mexico Acanthaceae Genera

Acanthoideae in Mexico

Acanthus 1 sp. intro to Pue; Andrographis 1 sp. intro to Pue, Tlx, Mor, and Ver; Anisacanthus 7 spp. native throughout all of Mexico, including 3 endemic to Mexico; Aphanosperma sinaloensis monospecific endemic to BC, BCS, Son, Sin, Chi, Dgo, Zac, NL, and Tam; Aphelandra 11 spp. native throughout all of Mexico, including 5 endemics; Barleria 1 sp. native to most of Mexico except BC, BCS, Son, and Sin; Bravaisia 3 Mexico + N neoendemic spp. native to much of Mexico except BC, BCS, Son, and Sin; Buceragenia 2 unplaced narrow endemics of C Mexico; Carlowrightia 26 spp. native throughout all of Mexico, including 15 endemics of Mexico, 7 of which are narrow endemics of Tam (3), Chi (2), Sin, and Yuc; Chalarothyrsus monospecific endemic of Nay, Jal, Col, Mch, Gro, Oax, and Pue; Chileranthemum 3 spp. native to most of Mexico except BC, BCS, Son, and Sin, and includes 1 narrow endemic of Jal + Gro; Dianthera 6-8 spp. native throughout all of Mexico, s/t included in Justicia now; Dicliptera 15 spp. native to all of Mexico; Dyschoriste ~20 spp. native throughout all of Mexico; Gypsacanthus monospecific endemic to Nay, Jal, Col, Mch, Gro, Oax, and Pue; Henrya 3 Americas endemic spp. native in all of Mexico, including 2 endemic to S+W Mexico; Holographis 18 spp. endemic genera found throughout all of Mexico; Hoverdenia monospecific endemic to Chi, Coa, NL, SLP, Dgo, Zac, and Ver; Hygrophila 2 spp. inc., 1 native and 1 intro to Nay, Jal, Col, Mch, Gro, Oax, Chp, Ver, Yuc, QR, Cam, and Tab; Hypoestes 1 sp. intro to much of Mexico exc BC, BCS, Son, Sin, Cam, Tab, Chp, Yuc, and QR; Justicia 20+ spp. native throughout all of Mexico; Lepidagathis 1-2 spp. native to Nay, Jal, Col, Gro, Mch, Oax, Chp, Pue, Mor, Ver, Cam, Tab, Yuc, and QR; Louteridium 9 Mexico + neoendemic spp. native to most of Mexico except BC, BCS, Son, and Sin, including 6 narrow endemics of Mch, Oax, Jal + Mch, Ver + Chp, Gro, and Tam; Mexacanthus monospecific endemic of Nay, Jal, Col, Mch, Gro, and Oax; Mirandea 6 Mexico endemic spp. native to most of Mexico except Pue, BC, BCS, Son, and Sin; Odontonema 4-7 spp. native in all of Mexico; Pachystachys 1 neoendemic sp. native to Chp, Cam, Tab, QR, and Yuc, and intro to Nay, Jal, Col, Gro, Mch, and Oax; Poikilacanthus 5 Mexico + neoendemic spp. native to Nay, Jal, Col, Mch, Gro, Oax, Chp, Pue, Tab, Cam, Yuc, and QR, including 4 endemic to Mexico; Pseuderanthemum 5-8 spp. native throughout all of Mexico; Ruellia ~50+ spp. native throughout all of Mexico, including ~20 endemic species; Sanchezia 1 former neoendemic sp. intro to Chp, Tab, Cam, Yuc, and QR; Spathacanthus 3 Mexico + CAM endemic spp. native to Nay, Jal, Col, Mch, Gro, Pue, Ver, Chp, Tab, Cam, Yuc, and QR, including 1 narrow endemic of Ver; Stenandrium 8-10 spp. native throughout all of Mexico; Stenostephanus 15 Mexico + neoendemic spp. native to most of Mexico except BC, Son, and Sin; Streblacanthus 2 Mexico & N neoendemic spp. native to Nay, Jal, Col, Mch, Gro, Oax, and Ver; Tetramerium ~25 sub & tropical Americas spp. native in all of Mexico, including 21 endemics of Mexico; Yeatesia 3 SE NAM endemic spp. native to Chi, Coa, NL, Tam, Dgo, Zac, SLP, Hgo, and Mex, including 1 endemic of NE Mexico. 

Avicennioideae in Mexico

Avicennia 2 spp. native to most of Mexico except C. Mexico.

Nelsonioideae in Mexico

Elytraria 4 spp. native to all of Mexico, inc. Mexican Pacific Is., including 2 endemics to Mexico; Nelsonia 1 sp. intro to Nay, Jal, Col, Gro, Mch, and Oax; Staurogyne 1 sp. native to Nay, Jal, Col, Mch, Gro, and Oax.

Thunbergioideae in Mexico

Mendoncia 3 spp. native to Nay, Jal, Col, Mch, Gro, Oax, Chp, Ver, Tab, Cam, Yuc, and QR; Thunbergia 3 spp. intro to much of Mexico except BC, BCS, Son, and Sin.

Neotropical Acanthaceae Genera

Acanthoideae in the Neotropics

Acanthus 1 sp. intro to Costa Rica; Ancistranthus monospecific endemic to Cuba; Andrographis 1 sp. intro to Bahamas, Cuba, Hispaniola, Leeward & Windward Is.; Anisacanthus ~9 spp. native to El Salvador, Honduras, Nicaragua, Costa Rica, E Brazil, inc. 5 narrow endemics of Nicaragua, Costa Rica, and E Brazil (3); Aphelandra 212 spp. native from Mexico S through CAM, Trinidad-Tobago, tropical SAM S to Peru, N Argentina exc. N Chile, Paraguay, and Uruguay, and intro in Cuba, Dominican Republic, and Windward Is.; Asystasia 2 spp. intro to Cuba, Belize, El Salvador, Honduras, Nicaragua, Antilles (exc. Netherlands Antilles), Venezuela, and SE Brazil; Barleria 1 sp. native to CAM, Colombia, Venezuela, Guyana, intro Bahamas, Antilles (exc. Cayman Is.), SW Caribbean, Trinidad-Tobago, French Guiana, and S Brazil; Barleriola 4 spp. Greater Antilles endemic genus of Cuba, Dominican Republic, Haiti, and Puerto Rico; Bravaisia 3 spp. native to CAM, Cuba, Colombia, Venezuela, and Trinidad-Tobago and intro to Venezuelan Antilles and Windward Is.; Brillantaisia 1 sp. intro Jamaica; Carlowrightia 4 spp. native to CAM (except Panama) and includes 1 narrow endemic in Ecuador; Cephalacanthus monospecific endemic of Peru; Chamaeranthemum 4 spp. neoendemic genus of Costa Rica, Peru, and SE+S Brazil, including 3 narrow endemics of Costa Rica (2) and Rio de Janeiro, SE Brazil; Chileranthemum 2 spp. native to Guatemala and El Salvador; Clistax 3 spp. endemic to N+E+S Brazil; Crossandra 1 sp. intro to the Antilles (except Cayman Is. and Netherlands Antilles), El Salvador, and Nicaragua; Cuenotia monospecific endemic of NE Brazil; Cyphacanthus monospecific endemic to Colombia; Dasytropis monospecific endemic to Cuba; Dianthera ~36 spp. native to CAM, the Antilles (exc. Cayman Is. & Netherland Antilles), and S through tropical SAM S to N Argentina (exc. N Chile), and intro Bermuda; Dichazothece monospecific endemic of SE Brazil; Dicliptera 20+ spp. native to CAM, Bahamas, Turks-Caicos, Greater Antilles (except Cayman Is.), Leeward & Windward Is., Trinidad-Tobago, and tropical SAM S to N Chile and N Argentina; Dyschoriste ~45 spp. native to CAM (except Belize), Cuba, Hispaniola, Venezuela, Ecuador, Peru, Bolivia, Paraguay, C+S+SE Brazil, N Argentina, and Uruguay, and intro Leeward Is.; Encephalosphaera 3 spp. N SAM endemic genus of Colombia, Ecuador, Peru, and N Brazil; Eranthemum 1 sp. intro to El Salvador, Antilles (excluding Puerto Rico, Netherlands Antilles, and Cayman Is.), Trinidad-Tobago, and Suriname; Fittonia 2 spp. native to Colombia, Venezuela, Ecuador, Peru, Bolivia, and N Brazil and intro to El Salvador and Trinidad-Tobago; Graptophyllum 1 sp. intro to Cuba, Hispaniola, Puerto Rico, Jamaica, Leeward Is, Venezuelan Antilles, Trinidad-Tobago, Honduras, Nicaragua, Panama, and Venezuela; Harpochilus 2 spp. narrow endemic genus of NE Brazil; Henrya 1 sp. native to CAM (excluding Belize); Herpetacanthus 21 spp. neoendemic genus of Costa Rica, Honduras, Nicaragua, Panama, Ecuador, French Guiana, Suriname, Peru, Bolivia, and N+E Brazil; Hygrophila 2-3 spp. native and intro to the Greater Antilles (exc. Cayman Is.), Trinidad-Tobago, CAM (exc. Costa Rica), and tropical SAM S to N Argentina (exc. N Chile); Hypoestes 1 sp. intro in Guatemala, El Salvador, Honduras, Panama, Colombia, and Paraguay; Isotheca monospecific endemic to Venezuela and Trinidad-Tobago; Justicia ~500 spp. native and widespread in CAM, Greater Antilles (exc. Cayman Is.), Leeward & Windward Is., Trinidad-Tobago, and tropical SAM S to N Argentina (exc. N Chile); Kalbreyeriella 4 spp. neoendemic genus native to Costa Rica, Panama, Colombia, N Brazil, Ecuador, and Peru; Lankesteria 1 sp. intro to Trinidad-Tobago; Lepidagathis ~50-60 spp. native to CAM, Cuba, Hispaniola, Puerto Rico, Leeward & Windward Is., Trinidad-Tobago, tropical SAM S to Peru, NW Argentina, Paraguay, and S Brazil; Liberatia 2 spp. SAM endemic genus of SE+S Brazil (not in APG); Louteridium 5 spp. native to CAM (exc. El Salvador), including 1 narrow endemic of Belize; Megaskepasma monospecific genus native to Suriname and Venezuela, now introduced in Costa Rica, Nicaragua, Panama, and Trinidad-Tobago; Morsacanthus monospecific endemic of S Brazil; Neriacanthus monospecific single-island endemic of Jamaica; Odontonema 32 spp. native from Mexico S through CAM, Cuba, Haiti, Leeward & Windward Is., Trinidad-Tobago, Ecuador, Colombia, Venezuela, N+E Brazil, and Guyana, and intro to Paraguay, the Dominican Republic, Puerto Rico, and Galapagos; Oplonia 16 spp. mostly neoendemic genus native to the Bahamas, Turks and Caicos, Cuba (8 endemics), Hispaniola, Jamaica (3 endemics), Puerto Rico, the Leeward Islands, Peru (2 endemics), Bolivia, and NW Argentina; Orophochilus monospecific endemic of Peru; Pachystachys 18 spp. native from S Mexico, Costa Rica, Panama, Cuba, Lesser Antilles (exc. Netherlands Antilles), and tropical SAM S to N Argentina (exc. Suriname, N Chile, and Uruguay), and intro Guatemala, El Salvador, Hispaniola, and Puerto Rico; Phaulopsis 1 sp. intro to Colombia and Jamaica; Phlogacanthus 1 sp. intro to Windward Is.; Poikilacanthus 9 spp. native to Guatemala (2 endemic), Honduras, Nicaragua, Panama, Venezuela (1 endemic), Peru (1 endemic), Bolivia, E+S Brazil (2 endemics), Paraguay, Uruguay, and N Argentina; Pranceacanthus monospecific endemic of N+C Brazil and Bolivia; Pseuderanthemum ~60 spp. native to CAM, Colombia, Venezuela, Brazil, Ecuador, Peru, Bolivia, intro Cuba, Puerto Rico, Leeward & Windward Is., Venezuelan Antilles, and Trinidad-Tobago; Psilanthele monospecific endemic to Ecuador; Pulchranthus 4 spp. N SAM endemic genus of Colombia, Venezuela, N Brazil, Suriname, French Guiana, Ecuador, Peru, and Bolivia; Rhombochlamys monospecific endemic of Colombia; Ruellia ~300 spp. native to CAM, Bahamas, Turks-Caicos, Aruba, Antilles (exc. Netherlands Antilles), Trinidad-Tobago, SW Caribbean, Galapagos, and tropical SAM S to N Argentina (exc. N Chile); Ruspolia 1 sp. intro to Trinidad-Tobago; Salpixantha monospecific endemic of Jamaica; Samuelssonia monospecific endemic of Haiti; Sanchezia 55 spp. native to Panama, Colombia, Venezuela, N Brazil, Ecuador, Peru, and Bolivia, and now intro to Guatemala, Belize, El Salvador, Honduras, Nicaragua, Costa Rica, Antilles (exc. Cayman Is, Netherlands Antilles), and Trinidad-Tobago; Sapphoa 2 spp. endemic genera of Cuba; Schaueria 15 spp. formerly endemic to C+E+S Brazil, but 1 sp. now intro in Trinidad-Tobago; Sebastiano-schaueria monospecific endemic to SE Brazil; Spathacanthus 3 spp. native to Guatemala, Honduras, and Costa Rica (1 endemic); Stenandrium 35-40 spp. native from S USA to Nicaragua (exc. Belize), plus Bahamas, Turks-Caicos, Cuba, Hispaniola, Puerto Rico, Leeward & Windward Is., and tropical SAM S to C Chile, N Argentina (exc. Guyana, Suriname, French Guiana, N Chile); Stenostephanus 95 spp. native from Mexico S through CAM (exc. Belize, El Salvador) to Colombia, Venezuela, N+SE Brazil, Ecuador, Peru, and Bolivia; Streblacanthus 3 spp. native to Guatemala, Costa Rica, Panama, Peru, and N Brazil; Strobilanthes 1 sp. intro to Belize, El Salvador, Honduras, Nicaragua, Panama, Cuba, Hispaniola, Jamaica, Puerto Rico, Windward Is., Venezuelan Antilles, and Trinidad-Tobago; Suessenguthia 8 spp. N SAM endemic genus of N Brazil, Peru, and Bolivia; Tetramerium 9 spp. native to Guatemala, El Salvador, Honduras, Nicaragua, Panama, Venezuela, Colombia, Ecuador, Peru (5 endemics), and Bolivia; Trichanthera 2 spp. neoendemic genus of Panama, Colombia, Venezuela, N Brazil, Guyana, Suriname, French Guiana, Ecuador, and Peru; Trichosanchezia monospecific endemic of Peru; Xantheranthemum monospecific endemic of Peru.

Avicennioideae in the Neotropics

Avicennia 3 spp. native to CAM, Bahamas, Aruba, Turks and Caicos, Antilles, SW Caribbean, Trinidad-Tobago, Colombia, Venezuela, Guyana, Suriname, French Guiana, N, E, and S Brazil, Uruguay, Ecuador, and Peru.

Nelsonioideae in the Neotropics

Aymoreana monospecific narrow endemic of E Brazil; Elytraria 11 spp. native to CAM, Cuba (6 endemics), Haiti (1 endemic), Aruba, Trinidad-Tobago, and tropical SAM S to Ecuador (1 endemic), Peru (1 endemic), NW Argentina, C+SE Brazil, and intro to Galapagos; Nelsonia 1 sp. intro to El Salvador, Honduras, Nicaragua, Panama, Puerto Rico, Colombia, Ecuador, French Guiana, Bolivia, and N+C+E Brazil; Staurogyne 28-30 spp. native from Nicaragua S to Colombia, Venezuela, Guyana, Suriname, French Guiana, Brazil, Bolivia, and Trinidad and Tobago.

Thunbergioideae in the Neotropics

Mendoncia ~74 spp. native to CAM (exc. El Salvador), Trinidad-Tobago, and tropical SAM S to Peru, Bolivia, Paraguay, and S Brazil; Thunbergia several spp. intro to Bahamas, Antilles (exc. Cayman Is., Netherlands Antilles), CAM (exc. Nicaragua), and tropical SAM S to N Argentina (exc. French Guiana, N Chile, and Uruguay).

Patagonia Genera Include:

Acanthoideae in Patagonia

Stenandrium 1 sp. native in Bio Bio in C Chile and also in Buenos Aires, Argentina, just N of Patagonia.

Additional Information and References

• Visit Lyrae’s Dictionary of Botanical Terms to learn the terminology of botanists. Note that if you hover over most of the words in the articles, you can also get definitions from them there.
• Willis, Lyrae (Unpublished). Plant Families of North America. This is where all of the family descriptions come from. Below should be most of my references for this, as well as my own personal observations of species in North America.
• Canadensys: Acadia University, Université de Montréal Biodiversity Centre, University of Toronto Mississauga, University of British Columbia. http://data.canadensys.net/explorer (accessed 2020 – current)
• Delta: Watson, L., and Dallwitz, M.J. (1992+). The Families of Flowering Plants: descriptions, illustrations, identification, and information retrieval. Version: 2nd May 2020. delta-intkey.com. Accessed spring through fall of 2020.
• Flora of North America. (1993+). https://floranorthamerica.org/Main_Page.
• GBIF.org (2020), GBIF Home Page. Available from: https://www.gbif.org
• Naturalista: CONABIO http://www.naturalista.mx (Accessed 2020–current).
• Neotropikey: Milliken, W., Klitgård, B., & Baracat, A. eds. (2009+). Neotropikey: Interactive key and information resources for flowering plants of the Neotropics. www.kew.org/neotropikey.com (accessed 2020 – current).
• Patagonia Wildflowers: Wildflower Identification Site. https://patagoniawildflowers.org/ Accessed throughout the fall of 2020.
• POWO (2019). Plants of the World Online. Facilitated by the Royal Botanic Gardens, Kew. Published on the Internet; http://www.plantsoftheworldonline.org/ Retrieved Winter 2020 – present.
• USDA, NRCS. 2020. The PLANTS Database (http://plants.usda.gov, 2 June 2020). National Plant Data Team, Greensboro, NC, USA; accessed throughout the fall of 2020.
• WFO (2022): World Flora Online. Published on the Internet: http://www.worldfloraonline.org. Accessed Spring 2022 – current

My Current Plant Family Education Fundraiser

I am currently seeking funding to expand my website and SEO capabilities as I keep adding new families, and I am also looking to invest in a new macro lens, as I will soon be adding floral dissections to the families as they become available to me. You can donate to help support native plant education using the GoFundMe link, also at the bottom of the page.

Copyright Information

The information and the photos on this site are free to use for educational purposes, with proper attribution. For other uses, please contact me first.

You can cite this site as follows: Willis, Lyrae (2020+). Lyrae’s Nature Blog – Plant Families of North America. https://lyraenatureblog.com/. Accessed [Enter Date].