Nesom, G.L 2010. Infrageneric classification of l/e/ftdy7a(Verbenaceae). Phytoneuron 2010-11: 1-15. Mailed 13 May 2010.
INFRAGENERIC CLASSIFICATION OF VERBENA (VERBENACEAE)
Guy L. Nesom
2925 Hartwood Drive
Fort Worth, TX 76109, USA
The genus Verbena sensu stricto in the present account includes 70 species (6 currently in the
process of description). The genus is divided into three sections: 1. Sect. VERBENA, type V.
officinalis (including 10 series: ser. Verbena; ser. Haleae Nesom, ser. now, type V. halei; ser.
Plicatae Nesom, ser. nov, type V plicata; ser. Simplices Nesom, ser. nov, type V simplex; ser.
Connaticarpae Nesom, ser. nov., type: V carnea; ser. Leptostachyae Schauer, lectoiype (designated
here) V. urticifolia; ser. Candelabrae Nesom, ser. nov., type V striata; ser. Bracteatae Nesom, ser.
nov., type V bracteata; ser. Californicae Nesom, ser. nov., type V californica; and ser. Tricesimae
Nesom, ser. nov., type V. canescens); 2. Sect. AifPHEPEIROS Nesom, sect, nov., type V. glabrata
(including 2 series: ser. Austrobrasilienses Nesom, ser. nov., type V hirta; and ser. Pacificae
Nesom. ser. nov., type V glabrata); and 3. Sect. VERBENACA Walpers, lectotype (designated here) V
bonariensis (including 2 series: ser. Pachystachyae Schauer, type V. bonariensis; and ser. Litorales
Nesom, ser. nov., type V. litoralis). The three sections are delimited primarily on the basis of
KEY WORDS: Verbena, Verbenaeeae, infrageneric classification, sections, series
The only inclusive, critical study of North American Verbena L. sensu stricto has been
provided by Perry (1933). Moldenke's contributions "toward a monograph of the genus" (1961-
1964) covered all of the taxa. but they were oriented toward nomenclature and literature and did not
provide evaluation of patterns of variation; nor did Moidenke provide a key to species, except in a
few regional floristic accounts. Since a recent overview by Sanders (2001), most of the native South
.American taxa have been examined in revisionary detail (O'Leary et al. 2007; Nesom 2010a); certain
groups of the North American species have been studied in detail (Nesom 2010b, 2010c, 2010f,
2010g). O'Leary et al. (2010) present a revision of the species they consider to represent lineages
apart from the primary ones of South America — included are species native to the USA Mexico,
South America, and Europe. The Flora of North America treatment (Nesom submitted) includes the
native and naturalized species of North America north of Mexico.
Verbena in the account here includes 70 species. Other recent estimates (e.g. Sanders 2001, "40
to 50" species; O'Leary et al. 2007 and 2010, 45 and 44 species, respectively) have been generally
similar, but Atkins (2004) estimated between 200 and 250 species, even though she treated both
Glandularia Gmelin and Junellia Moidenke as segregates of Verbena. The species of Verbena series
Pachystachyae Schauer (sensu O'Leary et al. 2007) are native to South America; five of these are
naturalized elsewhere in the work! Most of the remaining species are North American and Central
American, except for two European species, V. supina L. and V. officinalis L., which apparently are
most closely related to North American natives. Australian segregates of V officinalis have been
recognized (Michael 1997; Munir 2002; comments in Nesom 20 10b), Two species of northwestern
South America also are hypothesized here to be closely related to V officinalis.
Tribe Verbeneae Schauer includes Verbena, Glandularia (ca. 100 species), Junellia (ca. 30
species, including the monoUpic Urbania Phil.), and Mulguraea O'Leary & Peralta (19 species)
(O'Leary et al. 2009). Hierobotana Briq. (1 species, H. inflata (Kunth) Briq.) also has been included
among these (e.g., Atkins 2004), but its status apparently remains unresolved — its disposition was not
mentioned in O'Leary et al. (2009), even under the subheading "Relationship among genera of Tribe
Verbeneae; Verbena, Glandularia, Junellia and Mulguraea.'''' This group is characterized by fruits
that separate into four 1-seeded mericarps, mostly parallel anther thecae often with dilated and
glandular connective, and 2-lobed styles with the anterior lobe stigmatic. Glandularia has its center
of diversity in South America and Junellia and Mulguraea occur only in that area. The largest
number of Verbena species occurs in Mexico and the USA Botta (1989) included Tamonea Aublet
(6 species) as part of this group, but Atkins (2004) and O'Leary et al. (2008) have placed it in tribe
Casselieae. Verbena carnea Medik. has been treated as the monotypic genus Stylodon Raf, based
primarily on its mericarps that are connate at maturity, but in other features, V. carnea is similar to
North American species of Verbena and the connation of mericarps is interpreted here as a derived
feature within the genus. Recent DNA studies of the Verbeneae (Marx et al. in prep., Dick Olmstead
pers. comm.) indicate that both Hierobotana and. Stylodon evolved from within, the evolutionary
matrix of Verbena sensu stricto.
Phylogenetic reconstructions by Yuan and Olmstead (2008a, 2008b) indicate that Glandularia
and Verbena are monophyletic sister groups, together having a sister relationship to Junellia sensu
stricto (O'Leary et al. 2009). Phylogenetically basal to tribe Verbeneae is the newly described
Mulguraea, a genus, like Junellia, primarily of the arid Andean region.
The close it-latiutisbip between Verbena and Glandularia is emphasized by the discovery (Yuan
& Olmstead 2008a) that two independent intergeneric chloroplast transfers have occurred, both from
Verbena to Glandularia. "'One is from a diploid North American Verbena species [V. hastata or V.
orcuttiana, as sampled] to a polyploid North American Glandularia species [G. bipinnatifida (Nutt.)
Nutt, as sampled]. The other is more ancient, from the South American Verbena group [sect.
Verbenaca] to the common ancestor of a major Glandularia lineage [including G. canadensis (L.)
Nutt.], which has radiated subsequently in both South and North America."
Most, infrageneric classifications of Verbena have included Glandularia and/or Junellia, and
Verbena species have mostly been grouped in series or unranked groups (Walpers 1845; Schauer
1847; Briquet 1895; Small 1933; Troncoso 1974). Moldenke (1961) simply repeated the system of
Walpers. O'Leary et al. (2007) studied only South American species, placing them all in 2 subseries
within series Pachystachyae Schauer. O'Leary et al. (2010) divided the remaining species (ser.
Verbena) among three unranked groups; Verbena, Hastatae, and Bracteosae. Sanders (2001)
arranged the species of the southeastern USA into five informal groups. Among the few (14) species
of Verbena sensu stricto sampled in a molecular phylogenetic studies by Yuan and Olmstead (2008a,
2008b) and Yuan et al. (2010), essentially two main species groups are evident, corresponding
essentially to South American and North American species. Cladistic positions of the few-sampled
North American species are inconsistent among data sets and types of analyses.
In their classification of Verbena, O'Leary et al. (2007, 2010) have divided the species between
two groups, emphasizing two basic types of stem anatomy: Type A — cortical parenchyma continuous
and discrete along the circumference, not interrupted at the stem angles by columns of sclerenchyma
(their Fig. 2C); and Type B — cortical parenchyma interrupted at the stem angles by thick columns of
sclerenchyma joined to the angular tissue (their Fig. 2D). Type B anatomy is characterized externally
by a sharply 4-angled appearance and more prominent development of the angular nerves. All of the
species except V. rigida of their "subser. Pachystachyae" (= ser. Pachystachyae in the present
arrangement) are characterized by Type B anatomy. All of these are South American. O'Leary et al.
placed. South American species with Type A anatomy (excq^t for V. rigida) within subseries
Pseudoracemosae, a morphologically heterogeneous group dispersed here among ser.
Austrobrasilienses and ser. Verbena. Native North American species have Type A anatomy, fide
In preparation of a taxonomic treatment of" Verbena for the Flora of North America North of
Mexico. I have attempted to delimit natural groups within the genus.
The three sections are recognized within Verbena, primarily based on inflorescence structure.
1. Infloreseen^. paniculate, *\itli spiles ^ohtan ox irregularly arranged, not in definite 3's; spikes not
subtended by prominent foliaceous bracts, all spikes pedunculate; stem anatomy Type A
1. Inflorescence cymose, with spikes in definite 3's; spikes subtended or not by foliaceous bracts,
middle spike sessile or subsessile to pedunculate; stem anatomy Type A or B.
2. Spikes not subtended by foliaceous bracts; stems usually sharply 4-angled or (in ser. Litorales)
some not; leaves indistinctly petiolate through attenuate leaf bases; stem anatomy mostly Type B
2. Each spike subtended by foliaceous bracts; stems not sharply 4-angled; leaves distinctly petiolate
from truncate to cuneate leaf bases; stem anatomy Type A sect. Amphepeiros
A character of fruit morphology appears to be predictive, as inferred from its consistent
correlation with others in the distinction of natural groups. In some species, the developing fruit is
essentially flat at the apex, and the style base is inserted at that level, at the juncture of the four
nutlets. When the nutlets separate at maturity, the commissural faces appear to extend to the very tip
of the nutlets. In other species, the style base is inserted in a depression in the middle of the nutlets,
and when the nutlets separate at maturity, the dorsal side (the outer) of the nutlets is higher than the
ventral side (the inner, with the commissural face), giving the appearance that the commissural face
does not reach the nutlet apex.
Basis of the study
Thirty-two species occur in the FNANM flora area, and I also have studied representatives of
almost all of the rest of the species. The present report summarizes observations based on study of
the entire collections of Verbena sensu stricto (all geographic areas) from the following institutions:
ARIZ (800 collections). BRIT-SMU (ca. 1000), MO (ca. 1800), NLU (ca. 800), and TEX-LL (ca.
1200, the Moldenke Verbenaceae collection). The ability to study additional type specimens through
online images from F, GH, NY, US, and others has been especially useful. In addition to ^hs FNA
treatment (32 species, submitted), documentation is provided for various taxonomic decisions in a
series of collateral papers (Nesom 2010a, 2010b, 2010c, 2010d, 2010e, 2010f, 2010g).
The native geographic range of each species is broadly characterized below as USA, Mexico,
Central America, or South America. If a species occurs in more than one of these areas, the area of
widest distribution is listed first.
VERBENA L., Sp. PI. 1: 18. 1753; Gen. PI. ed. 5, 12. 1754. LECTOTYPE (Jarvis etal., List Linn. Gen.
Names Types, 98, 1993): Verbena officinalis L,
1. Section Verbena
Stems not sharply 4-angled; leaves broad to narrow, petiolate or basally attenuate, lobed or
unlobed, margins serrate; inflorescence paniculate, with spikes usually not in definite 3's; spikes not
subtended by foliaceous bracts, all spikes usually pedunculate; fruits remote to densely overlapping at
maturity. Stem anatomy Type A
la. Series VERBENA
Verbena [unranked] Schizophyllae Walpers, Repert. Bot. Syst. 4: 23. 1845. LECTOYPE (designated
here): Verbena officinalis L.
Verbena [unranked] Officinales Small, Man. S.E. Fl. 1135. 1933. TYPE: Verbena officinalis L.
Plants taprooted or fibrous-rooted; stems erect at the base, sometimes apparently strongly 4-
angled (perhaps similar to those of sect. Verbenacal); leaves petiolate to subpetiolate, lobed to
unlobed, blades thin, veins not impressed adaxially, margins serrate with acute teeth, not revolute;
spikes solitary to few, with a tendency to occur in pairs, especially at the proximal 1-2 nodes of the
inflorescence, fruits remote or becoming remote proximally; floral bracts usually shorter than the
calyx or equal; rachis glandular oi eglandulai ^.ommj^uijl faces reaching the nutlet tip.
Verbena officinalis L. Europe; 2n = 14, 28, 42, 56
Verbena supina L. Europe; 2n = 14
Verbena gaudichaudii (Briquet) P.W. Michael Australia
Verbena macrostachya F. Mueller Australia
Verbena sororia D. Don Australia/Africa
Verbena grisea Rob. & Greenm. South Anerica (Galapagos Islands)
Verbena demissa Moldenke South America (Ecuador)
Verbena caniuensis Moldenke South America (s Brazil)
Verbena filicauits Schauer South Anerica (Brazil, Sao Paulo)
Verbena gradSeseens (Chamisso) Herter South Anerica (Argentina, Bolivia, Paraguay. Uruguay):
Verbena swiftiana Moldenke South America (Argentina, Misiones; Brazil, Rio Grande do Sul)
Verbena townsendii Svenson South America (Ecuador, Galapagos Islands)
The widely dispersed nativity of ser. Verbena, as constituted here, is unusual compared to other
groups of the genus, which are geographically more coherent, and suggests that the geographical
subsets need to be examined for the possibility of greater evolutionary independence. Significant
differences between V. officinalis and V. supina suggest that even they are not most closely related to
each other. The South American species placed here also constitute a heterogeneous group,
morphologically and geographically.
Munir (2002) treated a group of morphologically and geographically distinct Australian
population systems at varietal rank within Verbena officinalis. Michael (1997) recognized three of
these taxa at specific rank (as above), distinct from naturalized V. officinalis, and the other two
probably should treated similarly (see comments in Nesom 20 10b). One of these Australian entities is
naturalized in Africa (or vice versa); another may be naturalized in Mexico (Chiapas) and Guatemala,
or else the latter plants represent an undescribed species (Nesom 2010b). Reported variability in
ploidy level (diploid, tetraploid, hexaploid, octopioid) gives plausibility to the view that
differentiation within V. officinalis sensu lato may include discrete evolutionary entities appropriately
recognized by formal nomenclature.
O'Leary et al. (2010) have indicated that Verbena sororia D. Don and V. officinalis var.
natalensis Hochst. ex C. Krauss are the correct names at specific and varietal rank for the taxon
treated in recent literature as Verbena africana (R. Fernandes & Verdcourt) P.W. Michael and V.
officinalis var. africana (R. Fernandes & Verdcourt) Munir. O'Leary et al, treat it at varietal rank but
have included other segregates, including the Australian taxa, as synonyms of typical V. officinalis.
Verbena grisea, an endemic of the Galapagos Islands, is distinct in its small, highly dissected
La\L ~\„nk drstnKued along the <tem 'terr^ ind lea 1 e-* mJ s f rprhte~ dinanl u ant' graMsh with
densely hispid-hirsute vestiture, spikes elongate and very slender, and tiny flowers and fruits (corolla
limb ca. 2 mm in diam., calyces 1.8-2 nun long, nutlets 1-1.2 mm long) slightly overlapping in fruit
and relatively compactly arranged. The spikes mostly in pairs are like those of ser. Verbena, as are
the nutlet commissural faces reaching the very tip. Its placement here is provisional but provides a
basis for a hypothesis regarding its occurrence in the Galapagos, especially since it would be
anomalous within any of the South American groups. In addition to images of the holotype and
isotype (GH!), I have examined the following: Galapagos Islands: Duncan Island, rare around 1250 ft,
15 Aug 1905-06, Stewart 3316 (CAS photo-LL!); Pinzon [Isla Pinzon = Duncan Island], near summit,
1200 ft, rare, fls light blue, to 70 cm, Sep 1975, van cler Werfj'2322 (LL!).
Verbena demissa is endemic to Andean Ecuador (known from provinces Azuay, Canar, and
Pichincha). It is distinctive in morphology: stems numerous, prostrate and sometimes apparently
rooting at the nodes, radiating from a thick, woody taproot; stems and rachises sparsely strigillose and
sparsely stipitate-glandular; leaves small (6-20 mm), short-petiolate, obovate or elliptic-obovate to
oblanceolate, the margins serrate with 2-3(-5) pairs of coarse teeth or shallow lobes; spikes relatively
short (1-7 cm) and few -flowered, mostly solitary, less commonly with paired proximal spikes, the
fruits becoming remote and somewhat divergent; flowers small (limbs ca. 2 mm in diam.); and fruits
1.6-1.8 mm, with commissural faces reaching the nutlet tips. Verbena demissa is similar to other
species of the group in features of habit, stem anatomy (fide O'Leary et al. 2010) and morphology,
glandular vestiture, the mostly solitary, short and few-flowered spikes, and nutlet morphology.
Verbena caniuensis is distinctive in its creeping habit and inflorescence reduced to a single
spike, habital features shared with the geographically similar V. filicaulis. O'Leary et al. (2007)
further discussed the distinctive inflorescence of V. caniuensis. On the other hand, its ovate-orbicular,
coarsely serrate, narrowly petiolate leaves are unusual in ser. Verbena.
Verbena filicaulis is unusual among species of South American Verbena in its deeply 3-parted or
pinnately 5-parted leaves, especially in combination wdth its apparently rhrzomjtous habit solitary
spikes, and larger flowers and fruits,. O'Leary et al. (2007) allied V. filicaulis with the species placed
here in sect. Amphepeiros ser. Austrobrasilienses.
Verbena swiftiana Moldenke is similar to V filicaulis in its deeply 3-lobed (with narrow
divisions) to coarsely toothed lower' and mid-cauline leaves and short, few-flowered, mostly
unbranched spikes with remote fruits. The stems are glabrous, mostly unbranched, and often
procumbent and rooting at the nodes. The type (isotype: NY digital image!) and the few other known
collections from northeastern Argentina (Misiones), with one collection from immediately adjacent
Brazil (Rio Grande do Sul).
Verbena gracilescens is a common and abundant species of central and southeastern South
America (Argentina, Bolivia, Paraguay, Uruguay). It characteristically produces relatively short
(mostly 5-15 cm), very slender spikes with remote fruits extending to the base or nearly so
(essentially without peduncles). The inflorescence is dichotomously branched, but often irregularly
so. The stems are branching, sometimes decumbent and nodally rooting, and glabrous or very
sparsely strigillose along the angles. Flowers are very small (calyces 1.2-1.5 mm), and the leaves are
sharply serrate and often tripartite, especially the basal to mid-cauline.
In their characteristic morphology, Verbena swiftiana and V. gracilescens are conspicuously-
different, but O'Leary et al. (2010) have treated them as conspecific varieties, apparently emphasizing
several cited specimens (without locality data) that are said to represent "una gradacion continua"
between the two. I have not seen the putative intergrades, but interspecific hybrids are not unsual in
Verbena and such have not been interpreted in other instances as evidence of conspecificity. O'Leary
et al., however, did not include Misiones, Argentina, or any of Brazil in the range of V. gracilescens.
thus its geographic range, apparently allopatric w r ith that of V. swiftiana, would preclude
hybridization. The putative intergrades cited possibly may be populational variants within V.
Moldenke (1968, 1971) recognized Verbena townsendii, V. galapagosensis Moldenke, V.
stewartii Moldenke, and V. glabrata var. tenuispicata Moldenke as native taxa of the Galapagos
Islands. From study in herbarium and field, Van del' Werff (1977) concluded that they all belong to
one single, extremely variable species (by far the most variable in the whole genus, in my
observations of collections at MO and TEX-LL), the oldest name being V. townsendii. According to
Van der Werff, differences in leaf width and lobing apparently result from habitat differences,
position on the stem, and maturation of the plants— juvenile leaves usually are broader. Forms of V.
townsendii are very similar to V. gracilescens.
lb. Series SlMPLICES Nesom, ser,. nov. Type: Verbena simplex Lehm.
Foliis sessilibus angustis nonlobatis, spicis 1 vel paucis fructibus dense superpositis, vestimento
eglanduloso, et nuculis superficiebus commissuralis apices attengentibus distinctus.
Plants taprooted; leaves linear to narrowly lanceolate or narrowly oblong-oblanceolate, sessile,
unlobed, margins few-toothed, not revolute, blades thick with veins not impressed adaxially; spikes
mostly 1 or few from proximal branches, fruits remaining dense and overlapping; floral bracts shorter
than the calyces; rachis eglandular; commissural faces appaix *! w\ten In * c npLtJ' to the nutlet
Verbena simplex Lehman USA; 2n = 14
Verbena simplex has no apparent close relatives, at least in eastern North America. It is similar
to V carnea in its tendency to produce sessile, unlobed leaves and fruits with commissural faces
extending completely to the nutlet tips.
O'Leary et al. (in press) have treated Verbena orcuttiana as conspecific with V simplex. The
two differ in growth habit, vestiture, leaf arrangement, and floral features; they are very different in
ecology and their native geographic ranges at their closest point are disjunct by more than 1100 miles.
Verbena orcuttiana lias many similarities with V. californica and V. abramsii, and those three species
are treated here as ser, Californicae. Given the apparently isolated position of V. simplex in the
eastern USA it would be reasonable, at least as a hypothesis, to consider the possibility that it is
closely related to ser. Californicae.
le. Series CONNATICARPAE Nesom, ser. nov. TYPE: Verbena cornea Medikus
Duratione perenni habitu rhizomato, foiiis sessilibus, spicis plerumque solitariis, floribus relative
amplis distinctus, et nuculis connatis non discedentibus ad maturitatem.
Plants rhizomatous; leaves sessile, oblong-spatulate, unlobed, margins closely serrate to
irregularly crenate-serrate, revolute, blades thick with veins impressed adaxially; spikes mostly 1 or
few, slender, fruits becoming remote; floral bracts usually shorter than the calyx or equal; rachis
eglandular; nutlets connate, not separating at maturity, commissural faces apparently extending
completely to the nutlet tips.
Verbena carnea Medikus USA
Sanders (2001) hypothesized that Verbena carnea is close to V. stricta (here placed in ser.
Candelabrae), but the rhizomatous habit and the thickened, unlobed leaves with closely serrate
margins are without a close match elsewhere in the genus. The reduced inflorescence and the connate
nutlets are specialized features, suggesting that V. carnea is derived from some North American
group. There is a tendency in a number of North American species for the nutlets to remain adherent
until very late in ontogeny, and the developmental persistence of this feature in V. carnea is hardly a
character that would justify segregation at generic rank.
O'Leary et al. (2010) have adopted Verbena caroliniana Michx. (1803) as the correct name for
this species, as preferred over the earlier V. carnea Medikus (1784). Comments and a neotype
justifying retention of the Medikus name are provided by Nesom (20 lOd).
Id. Series L.EPTOSTACHYAE Schauer in DC, Prodr. 11: 545. 1847. LECTOTYPE (designated here):
Verbena urticifolia L. Troncoso (1974, p. 311) designated Verbena officinalis as the lectotype of
series Leptostachyae, but V officinalis is automatically the type of series Verbena.
Plants taprooted or fibrous-rooted; leaves petiolate, unlobed, margins serrate with acute teeth,
blades thin with veins not impressed adaxially; spikes numerous, often strictly in 3 's at lower nodes,
slender, fruits distantly remote; floral bracts usually shorter than the calyx or equal. laJu* egl.mdulai ,
commissural faces extending to very tip of nutlets.
Verbena Carolina L. Mexico, sw USA, Central America; In = 14
Verbena ehrenbergiana Schauer Mexico; 2n = 14
Verbena scabra Vahl USA. West Indies, Mexico
Verbena urticifolia L. USA 2n = 14
The plants of ser. Leptostachyae are easily recognizable by their eglandular vestiture, numerous,
long, very slender spikes with remote fruits, tiny corollas, and nutlets with commissural faces
^ .kiulinv l<- vu l . Iip^'^v .^..in _'"!"■. i
le. Series CANDELABRAE Nesom, ser. nov. TYPE: Verbena stricta Ventenat
Verbena [unranked] Hastatae Small, Man. S.E. Fl. 1135. 1933. TYPE: Verbena hastata L.
Foiiis latis grosse serrato et spicis numerosis crassiusculis fructibus dense superpositis distinctus.
Plants taprooted or fibrous-rooted; leaves distinctly petiolate to subsessile, unlobed, margins
usually coarsely serrate to incised with acute teeth, blades thickened with veins impressed adaxially;
spikes numerous and clustered from distal nodes, thick, fruits densely overlapping; floral bracts
usually shorter than the calyx or equal; rachis eglandular; commissural faces extending to very tip of
Verbena hastata L. USA; 2n = 14
Verbena macdougalii Heller USA, Mexico; In = 14
Verbena stricta Ventenat USA; 2n = 14
Verbena xutha Lehman USA; 2n = 42
Verbena stricta and V. macdougalii are very similar between themselves and probably related as
sister species. Verbena hastata stands apart in its reduced vestiture and relatively long-petiolate
leaves with serrate margins; a close relationship with ser. Leptostachyae should be investigated.
Verbena xutha is provisionally placed here, emphasizing its eglandular vestiture, spikes arising from
distal branches and often remaining relatively compact, and nutlets with commissural faces extending
to very tip of nutlets. The laeiniate leaves of V. xutha, however, are more similar to some of those of
ser. Plicatae. The polyploid chromosome number of V. xutha at least allows the possibility that it
incorporates more than one genome.
If. Series BRACTEATAE Nesom, ser. nov. TYPE: Verbena bracteata Lag. & Rodr.
Verbena [unranked] Bracteosae Small, Man. S.E. Fl. 1135. 1933. TYPE: Verbena bracteata Lag. &
Rodr. (incl. Verbena bracteosa Michx.)
Foliis latis serrato-incisis, spicis densis bracteis longi-protrusis, et fruetibus ad maturitatem plus
minusve remotis distinctus.
Plants taprooted or fibrous-rooted; leaves petiolate to subsessile, often 3-lobed, margins serrate
to deeply incised with acute teeth, blades relatively thin, veins not impressed adaxially; spikes few,
thick, fruits densely overlapping but sometimes becoming somewhat remote at maturity; floral bracts
becoming much longer than the calyx and coiolla. uchis -glandulai, eommi'-smal faces extending to
very tip of nutlets.
Verbena bracteata Lagasca & Rodr. USA, Mexico; 2n = 14, 28
Speuilizjhun^ of Verbena bracteata \±\ habit (prostrate) and inflorescence (mostly solitary,
elongate spikes with greatly enlarged bracts and relatively large fruits) give the species a distinctive
appearance. The petiolate, incised leaves, eglandular vestiture, and nutlets with commissural faces
extending completely to the tip are similar to those of V. xutha.
lg. Series HALEAE Nesom, ser. nov. TYPE: Verbena halei Small
Foliis crassibus venis adaxialiter impressis marginibus revolutis caulium lobatis et spicis
numerosibus fruetibus late remotis ad maturitatem distinctus.
Plants taprooted; leaves petiolate to subpetiolate, basal lobed to unlobed, cauline lobed, margins
serrate with acute teeth, blades thick veins impressed adaxially; spikes numerous, slender, fruits
becoming remote; floral bracts usually shorter than the calyx or equal; rachis eglandular;
commissural faces ending below the nutlet tips.
Verbena halei Small USA, Mexico; 2n = 14
Verbena halei has been treated as element of V. officinalis, as V. halei subsp. halei (Small) S.
Barber, but the two rarely if ever have the opportunity even to hybridize, much less to intergrade.
The consistent morphological differences and continental disjunction in native range support the
I of V. halei at specific rank.
An individual of Verbena menthifolia from Arizona studied by Yuan and Olmstead (2008b)
was heterozygous at both the PHOT1 and PHOT2 nuclear gene loci, and the gene trees indicated that
the individual was of hybrid origin, with V. halei as one of the putative parental species.
lh. Series PLICATAE Nesom, ser. nov. TYPE: Verbena plicata Greene
Foliis latis plerumque 3-lobatis segmentis inciso-dentatis venis saepe abaxialiter prope margines
albidis el spicis 1 velpaueis di-tinctus
Plants taprooted; leaves usually petiolate, relatively broad (oblong-ovate or obtusely elliptic-
ovate), cauline sometimes subclasping, often 3-parted, margins coarsely serrate to incised-serrate or
pinnately lobed-serrate, blades thick, veins impressed adaxially, often whitish abaxially near the
margins; spikes 1 or few, dense with overlapping fruits to elongate and slender with fruits becoming
remote; floral bracts usually shortei ilru< the .. t ih\ >! equal uJii usujiH "hndu^ai ~omjrussUial
faces ending below the nutlet tips (except in V. xutha).
Verbena cloverae Moldenke USA; In = 14
Verbena plicata Greene USA Mexico; 2n = 14
Verbena runyonii Moldenke USA 2n = 14
Verbena lasiostachys Link (incl. V. robusta Greene, V. prostrata W.T. Ait.) exico; 2n = 14
Among these species, Verbena plicata and V. cloverae share a distinctive feature of the nutlets —
the commissural faces are bullate with low plates densely packed and perhaps connate, forming
essentially an unbroken white surface. The Californian V. lasiostachys appears to belong in ser.
Plicatae but is distinct in geography compared to the others, which are mostly in the south-central
USA. O'Leary et al. (2010) treated V. runyonii as a synonym of V. neomexicana var. hirtella Perry.
li. Series CALIFORNICAE Nesom, ser. nov. TYPE: Verbena californica Moldenke
Foliis plerumque oblanceolatis dentatis, fructibus dense imbricatis vel remotis, rhachidibus
calycibusque glandulosis, etnuculis superficiebus commissuralis apices attengentibus distinctus.
Plants taprooted; leaves elongate, not lobed, without distinct petioles, margins toothed, revolute,
surfaces not glossy, veins impressed adaxially; spikes 1 or 2-5 from medial to distal branches,
relatively thin, fruits not overlapping or densely overlapping but becoming remote proximally; floral
bracts shorter than the calyx or equal; rachises and calyces glandular; commissural faces extending
completely to the nutlet tips
Verbena abramsii Moldenke USA
Verbena californica Moldenke USA
Verbena orcuttiana Pern' Mexico
These three species are very similar in aspect to those of ser. Tricesimae. Their recognition here
as a separate group emphasizes the distinctive nutlet morphology and their Californian geography
(Nesom 2010 f, in manuscript).
Ij. Series TRICESIMAE Nesom, ser. nov. TYPE: Verbena canescens Kunth
Folu 3 eionoatts nmnatiiidus \el pciiiu* daitahs, lamiius incrassatis venis adaxaiiter impressis
marginibus revolutis, spicis 1 vel paucis relative tenuibus fructibus plerumque proxime remotis
Plants taprooted; leaves elongate, pinnatifid to deeply toothed (incised-pinnatifid or incised
dentate, varying to subentire), blades thickened., veins impressed adaxially, margins revolute, surfaces
glossy; spikes 1 or few, relatively thin, fruits becoming remote proximally; floral bracts shorter than
the calyx or equal; rachises glandular or eglandular; commissural faces not reaeliing the nutlet apex.
Verbena canescens Kunth Mexico, USA; 2n = 14
Verbena gracilis Desfontaines Mexico, USA
Verbena hirteila (Perry) Nesom, ined. Mexico, USA; 2n = : 14
Verbena jessicae Nesom & Hinton, ined. Mexico
Verbena johnstonii (Moldenke) Nesom Mexico
Verbena livermorensis Turner & Nesom, ined. USA, Mexico
Verbena moranii Nesom, ined. Mexico
Verbena neomexicana Small Mexico, USA; In = 14
Verbena nitens Nesom, ined. Mexico
Verbena perennis Wooton USA; 2n = 14
Verbena pinetorum Moldenke Mexico, USA
Verbena subuligera Greene Mexico
Verbena xylopoda (Perry) Nesom ined. USA, Mexico
The sectional epithet alludes to the 30th parallel, which most of the species are near. Verbena
canescens and V. gracilis have wide ranges compared to the others, from the southwestern USA to
south-central Mexico. Verbena abramsii, V californica and V. orcuttiana, at the northwestern corner
of this group, stand apart from the other species in their elongate, serrate leaves and commissural
faces of the nutlets extending completely to the nutlet tips — these perhaps represent a distinct group.
The species of ser. Trices imae are treated in detail in Nesom (2010g, in manuscript) and Nesom and
Hinton (2010, in manuscript; V. jessicae), where the species noted above as "ined." will be formally
described or delimited.
Sanders (2001) hypothesized that Verbena neomexicana is part of the species group that includes
V. menthifolia, and indeed they have similarities in. habit. Verbena menthifolia, however, and its
putatively close relative V. madrensis have thinner leaves with non-revolute margins and veins not
impressed adaxially, and the commissural faces generally extend completely to the nutlet tips.
2. SECTION AMPHEPEIROS Nesom, sect. nov. TYPE: Verbena glabrata Kunth
Inflorescentiis cymosis spicis in. 3s, quoque spica per folia vel bracteas foliaceas subtenta,
et foliis latis distincte petiolatis e basi truncatis vel cuneatis marginibus grosse serratis distinctus.
Stems not sharply 4-angled (Type A anatomy); leaves broad, distinctly petiolate from truncate to
euneate leaf bases, unlobed, margins coarsely serrate; inflorescence cymose, with spikes in definite
3's; each spike subtended by foliaceous bracts, often with the middle spike sessile or subsessile to
short-pedunculate; fruits usually densely overlapping at maturity.
2a. Series PACIFICAE Nesom, ser. nov. TYPE: Verbena glabrata Kunth
Distributione geographica plerumque secus oceanum pacificum distinctus.
Verbena glabrata Kunth South America (Bolivia, Ecuador, Columbia, Peru)
Verbena macrodonta Perry Mexico (Raja California Sur)
Verbena recta Kunth Mexico
Verbena sedisla Moldenke South America (Galapagos Islands)
Species of ser. Pacificae are autochthonous to both the South American and North American
(also see ser. Pachystachyae regarding V. sphaerocarpa; ser. Verbena is the only group
hypothesized here to be more widepread). The separation of ser. Brasilienses and ser. Pacificae,
based on geography, hypothesizes that other distinctions remain to be discovered; a clear
morphological difference is not apparent, but the geographically-based names provide reference to the
groups. Tt also is acknowledged that the separation may be arbitrary.
Verbena macrodonta is one of a number of endemic species of the oak and pine-oak woodlands
of the Sierra de la Laguna of Baja California Sur. Pine-oak forests closest to those of the Sierra de la
Laguna are in the trans -volcanic ranges of southeast and south-central Mexico, the "Serranias
Meridionales" floristic province, tide Rzedowski (1978). Pine-oak forests of northern Baja California
(Sierra Juarez, Sierra San Pedro Martir) are more closely related floristically to the USA.
1 have seen only the holotype (MO!) and isotype (US digital image!) of Verbena macrodonta,
but the distinctive leaf morphology and inflorescence structure, as well as its geography, justify its
placement among these species. The leaves are large, broadly lanceolate to oblong-lanceolate with
coarsely serrate margins and truncate or rounded bases and distinct petioles, and the spikes are dense,
subtended by bracts, and distinctly in 3's. Verbena macrodonta and V. recta both, are unusual in sect.
Amphepeiros because of their pedunculate spikes. O'Leary et al. (2010) have placed V macrodonta
as a synonym of V. officinalis.
Verbena glabrata is native to western South America. O'Leary et al. (2007) identified and cited
far-disjunct collections from Mexico (Michoacan, Puebla, and Veracruz) as V. glabrata, but these
Mexican plants are V. recta. O'Leary et al. (2010) have recognized V. recta as distinct but without
clarifying their earlier equation of it with V. glabrata. I have seen collections of V. recta from the
Mexican states of Distrito Federal, Edo. Mexico, Michoacan, Morelos, Nuevo Leon, Oaxaca, and
Puebla. The populations in Nuevo Leon appear to be disjunct from the others but morphologically
Collections identified as Verbena glabrata from the southernmost portion of its range (Depto.
Arequipa in Peru) are of prominently glandular plants with trilobed and more elongate leaves than
characteristic elsewhere. It is probable that these represent an undescribed species.
2b. Series AUSTRO BRASILIENSES Nesom, ser. nov. TYPE: Verbena hirta Sprengel
Distibutione geographica plerumque in Brasilia auslrali distinctus.
Verbena hirta Sprengel South America (s Brazil, ne Argentina)
(tentatively including var. hirta and var. gracilis Dusen)
Verbena lobata Velloso South America (s Brazil)
(tentatively including var. lobata and var. glabrata Moldenke)
Verbena subpetiolata N. O'Leary 7 South America (s Brazil)
All three species of ser. Austrobrasilienses are centered in southernmost states of Brazil, Parana,
and Rio Grande do Sul, hence the series epithet. This is a morphologically heterogeneous assemblage
needing further study.
3. SECTION Verbenaca Walpers, Repert. Bot. Syst. 4: 14. 1845. LECTOTYPE (designated here):
Verbena bonariensis L. Sect. Verbenaca of Walpers included Verbena, Glandularia, and
Junellia. The lectotype is chosen here to represent to restrict the section to Verbena sensu stricto.
Schauer (1847) followed Walpers in his broad concept of sect. Verbenaca, placing V officinalis
within sect. Verbenaca series Lepiosiachyae.
Stems usuall} sharply 4-angled (Type B anatomy); leaves broad to narrow, indistinctly petioiate
thiouglt aienuaL Lii biSw unlobui irsiiin.n^ w srsely serrate to subentire; inflorescence cymose,
with spikes in definite 3's; spikes not subtended by fbiiaceous bracts, often with the middle spike
sessile or subsessile to pedunculate; fruite densely overlapping or becoming remote at maturity.
3a. Series PACHYSTACHYAE Schauer in DC, Prodr. 11: 539. 1847. LECTOTYPE (Troncoso 1974, p.
311): Verbena bonariensis L. O'Leary et al. (2007, p. 580) cited "serie Pachystachyae subserie
Pachystachyae Schauer," perhaps supposing that the subseries was automatically established.
"Subseries Pachystachyae" is not a legitimate name.
Verbena [unrankedj Foliosae Walpers, Repert. Bot. Syst. 4: 18. 1845. LECTOYPE (designated here):
Verbena bonariensis L.
Verbena [unranked] Micranthae Walpers, Repert. Bot. Syst. 4: 18. 1845. LECTOYPE (designated
here): Verbena bonariensis L.
Verbena [unranked] Holophyllae Walpers, Repert. Bot. Syst. 4: 18. 1845. LECTOYPE (designated
here): Verbena bonariensis L.
Verbena [unranked] Bonarienses Small, Man. S.E. Fl, 1135. 1933. TYPE: Verbena bonariensis L.
Verbena [unranked] Venosae Small, Man. S.E, Fl. 1 135. 1933 TYPE: Verbena rigida Spreng.
Fruiting spikes relatively short and thick, the central sessile to subsessile, with fruits usually
densely overlapping at maturity. Leaves unlobed.
Verbena alata Otto ex Sweet South America
Verbena bangiana Moldenke South America
Verbena bonariensis L. South America; 'In = 14, 28
Verbena brasiliensis Velloso (incl. V intercedens Briquet) South America
Verbena ephedroides Chamisso South America
Verbena goyazensis Moldenke South America
Verbena hispida Ruiz & Pavon South America; 2n = 14
Verbena incompta P.W. Michael South America
Verbena intermedia Gillies & Hooker ex Hooker South America; 2n = 28, 35, 56
Verbena lindbergii Moldenke South America
Verbena ovata Chamisso South America; In =- 72
Verbena rigida Sprengei South America; 'In = 42
Verbena sagittalis Chamisso South America
Verbena sphaerocarpa Perry Mexico (Socorro Island)
Verbena valerianoides Kunth South America
Verbena rigida was observed by O'Leary et al. (2007) to have Type B stem morphology, unlike
the rest of the section. It also is unusual in it rhizomatous habit, but in features of the inflorescence it
is similar to the species placed here in ser. Verbenacae.
Verbena sphaerocarpa is tentatively recognized at specific rank (Nesom 2010a). It is endemic
to Socorro Island (about 600 kilometers west of the coast of Colima, Mexico) but is very similar to V.
brasiliensis and probably derived from it.
Verbena valerianoides is a distinctive species apparently endemic to montane Colombia (the
type from Bogota, P fiche!) It produces sessile, non-clasping, narrowly lanceolate to oblong-
lanceolate, entire leaAes and short thiJ i r> ss the cen'i s] cne ^hL O'Leary et al. (2007)
considered this a "doubtful taxon" but I have seen recent collections from the departments of Boyaca,
Cundinamarca, and Narino.
Verbena bangiana was treated by O'Leary et al. (2007) as V. hispida var. obovata (Moldenke)
O'Leary, who noted that they 7 did not consider differences in vestiture and floral dimensions between
the two taxa as "sufficiently important in Verbena'' to sq?arate them as distinct species. Collections
of each are numerous and intermediates appear to be rare, suggesting that the two are reproductively
Verbena goyazensis (Bull. Torrey Bot. Club 77: 404. 1950. TYPE: Brazil. Goias. Rio do Peixe,
8 Jul 1949, G. Hashimoto 663 [holotype: SP, fragment-NY digital image!]) has broad, sessile, serrate
leaves and very short, congested spikes in 3's — it appears to be remarkably distinct in its leaves with
deeply reticulate-excavate abaxial surfaces. It has been included by O'Leary et al. (2010) as a
3b. Series LlTORALES Nesom, ser. nov. TYPE: Verbena litoralis Kunth
Spicis fructiferis relative elongatis gracilibusque fructibus proximalibus remotis ad maturitatem
etfoliis nonlobatis distinctus.
Fruiting spikes elongate and slender, the central pedunculate, with fruits becoming remote at
maturity, at least proximally; leaves unlobed.
Verbena litoralis Kunth South America (western); 2n = 28, 42, 56
Verbena montevidensis Sprengel South America (southeastern); 2n = 21, 42
Both of these species, as currently identified, appear to be polymorphic. Potential correlations
between ploidy level and morphology apparently have not been investigated.
This study was done in conjunction with preparation of the FNA treatment of Verbena and
supported by the Flora of North America Association. I am grateful to Nataly O'Leary for providing
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