A Synopsis, New Combinations, and Synonyms in Acanthocladus (Polygalaceae)

Abstract

A partir do estudo das coleções de herbário, uma sinopse de Acanthocladus Klotzsch ex Hassk. (Polygalaceae) é apresentada, incluindo chave de identificação para as oito espécies aceitas. Foram feitas também duas novas sinonimizações e as seguintes novas combinações: A. dukei (Barringer) J. F. B. Pastore & D. B. O. S. Cardoso, A. pulcherrimus (Kuhlm.) J. F. B. Pastore & D. B. O. S. Cardoso e A. santosii (Wurdack) J. F. B. Pastore & D. B. O. S. Cardoso. Além disso, os nomes A. brasiliensis Klotzsch ex Hassk. e A. pulcherrimus foram lectotipificados.

Full text

A Synopsis, New Combinations, and Synonyms in
Acanthocladus (Polygalaceae)
Jose
´
Floriano Bare
ˆ
a Pastore* and Domingos Benı
´
cio Oliveira Silva Cardoso
Laborato
´
rio de Sistema
´
tica Molecular de Plantas, LAMOL, Universidade Estadual de Feira de
Santana, UEFS, Av. Transnordestina s/n, Campus, Feira de Santana, Bahia, CEP 36-900, Brazil.
*Author for correspondence: jfpastore@hotmail.com
Gerardo A. Aymard C.
Programa de Ciencias de Agro y del Mar, Universidad Nacional Experimental de Los Llanos
Occidentales Ezequiel Zamora (UNELLEZ)–Guanare, Herbario Universitario (PORT), 3350
Mesa de Cavacas, Portuguesa, Venezuela
ABSTRACT . A synopsis of the American genus
Acanthocladus Klotzsch ex Hassk. (Polygalaceae),
based primarily on herbarium studies, is presented,
along with an identification key to the currently
accepted eight species. Two new synonyms and the
following new combinations are presented: A. dukei
(Barringer) J. F. B. Pastore & D. B. O. S. Cardoso, A.
pulcherrimus (Kuhlm.) J. F. B. Pastore & D. B. O. S.
Cardoso, and A. santosii (Wurdack) J. F. B. Pastore &
D. B. O. S. Cardoso. The names A. brasiliensis
Klotzsch ex Hassk. and A. pulcherrimus are lectoty-
pified.
R
ESUMO . A partir do estudo das colec¸o
˜
es de
herba
´
rio, uma sinopse de Acanthocladus Klotzsch ex
Hassk. (Polygalaceae) e
´
apresentada, incluindo chave
de identificac¸a
˜
o para as oito espe
´
cies aceitas. Foram
feitas tambe
´
m duas novas sinonimizac¸o
˜
es e as
seguintes novas combinac¸o
˜
es: A. dukei (Barringer) J.
F. B. Pastore & D. B. O. S. Cardoso, A. pulcherrimus
(Kuhlm.) J. F. B. Pastore & D. B. O. S. Cardoso e A.
santosii (Wurdack) J. F. B. Pastore & D. B. O. S.
Cardoso. Ale
´
m disso, os nomes A. brasiliensis Klotzsch
ex Hassk. e A. pulcherrimus foram lectotipificados.
Key words: Acanthocladus, Central America, Po-
lygala, Polygalaceae, South America.
Acanthocladus Klotzsch ex Hassk. (Polygalaceae)
comprises eight species, occurring from seasonally dry
to moist forests in South and Central America. The
first species of the genus, A. brasiliensis Klotzsch ex
Hassk., was originally described (Saint-Hilaire &
Moquin-Tandon, 1828) within the African genus
Mundia Kunth. Klotzsch noted that M. brasiliensis
A. St.-Hil. & Moq. could represent a new genus and
wrote the name Acanthocladus on herbarium sheets,
but never published it. Subsequently, Hasskarl
(1863–1864) validly published this genus, and
Bennett (1874) accepted it and recognized an
additional species. Nevertheless, succeeding taxo-
nomic works treated Acanthocladus either as a section
(Chodat, 1891–1893; Marques, 1984) or subgenus
(Paiva, 1998) within the larger genus Polygala L.
Recent phylogenetic studies based on molecular data
(Persson, 2001; Forest et al., 2007) have shown the
broad polyphyly of Polygala and strongly support the
generic circumscription of Acanthocladus.
The species of Acanthocladus may be recognized by
the combination of the following characters: habit
shrubby to arborescent, with usually sharply thorny
branches; leaves mostly coriaceous to subcoriaceous;
flowers papilionaceous and usually congested in
brachyblasts, sometimes fasciculate or rarely in
racemes with a conspicuous rachis as in A. santosii
(Wurdack) J. F. B. Pastore & D. B. O. S. Cardoso;
sepals caducous in fruit; and capsules woody and
dehiscent. Although most of these characters can be
said to be plesiomorphic (Persson, 2001), together
they are useful in distinguishing Acanthocladus from
the remaining genera of Polygalaceae.
During our ongoing revision of the Polygala species
of Bahia State, Brazil, we found it worthwhile to
improve the taxonomy of Acanthocladus, making use
of the results of recent molecular phylogenetic
studies. These works supporting the recognition of
Acanthocladus make it necessary to validate new
combinations for species in the genus. Eriksen et al.
(2000), in their treatment of Polygalaceae in Ecuador,
provided only one new combination and described one
new species of Acanthocladus. Having reevaluated the
circumscription of Acanthocladus, we present here a
synopsis of the genus, including an identification key
to all currently accepted species, new synonyms, and
taxonomic transfers for the remaining species.
doi: 10.3417/2009030 NOVON 20: 317–324. PUBLISHED ON 13 SEPTEMBER 2010.

I. Acanthocladus Klotzsch ex Hassk., Ann. Mus.
Bot. Lugduno-Batavum 1: 184. 1864. Polygala
L. sect. Acanthocladus (Klotzsch ex Hassk.)
Chodat, Me
´
m. Soc. Phys. Gene
`
ve 31(2): 6.
1893. Polygala L. subg. Acanthocladus (Klotzsch
ex Hassk.) Paiva, Fontqueria 50: 146. 1998.
TYPE: Acanthocladus brasiliensis Klotzsch ex
Hassk.
Shrub to tall tree (25 m or taller); branches usually
ending in sharp thorns. Leaves subopposite or alternate,
mostly coriaceous to subcoriaceous (membranous in A.
brasiliensis and A. guayaquilensis B. Eriksen & B.
Sta
˚
hl). Inflorescence usually an axillary, congested
brachyblast, sometimes appearing fasciculate or rarely
a raceme with a conspicuous rachis. Flowers papiliona-
ceous, pedicellate; sepals caducous in fruit, free; petals
usually whitish purple; carina with apex not crested;
stamens 8, the filaments partly joined into a sheath and
adnate to lower part of carina; gynoecium curved.
Capsule oblate, compressed, dehiscent, pericarp woody;
seeds usually 2, puberulent to pubescent, ovoid, with a
conspicuous white, carnose aril.
Etymology. The name Acanthocladus is from the
Greek for ‘‘acantha’’ (spine or thorn) and ‘‘clados’’
(branch), due to the branches ending in thorns, as
commonly found in most species.
IDENTIFICATION KEY FOR ACANTHOCLADUS SPECIES IN CENTRAL AND SOUTH AMERICA
1a. Flowers not in congested racemes, the fertile axis conspicuous, 10–25 mm long .................7.A. santosii
1b. Flowers in very congested racemes, resembling fasciculate umbels, the fertile axis absent to 1 mm long.
2a. Leaves opposite to subopposite.
3a. Tree to 25 m high; leaves ovate; rudimentary petals 2.5–3 mm long, spatulate; Amazon moist forest. . .
...............................................................8. A. scleroxylon
3b. Shrub, treelet, or tree to 15 m high; leaves ovate-elliptic; rudimentary petals 0.5–1.5 mm long, oblong to
narrowly oblong; seasonally dry forest.
4a. Tree to 15 m high; terminal thorns slender to obsolete when mature; leaves rigidly coriaceous,
papillate on abaxial surface; pedicels 4–5 mm long; Colombia ............... 3.A. colombianus
4b. Shrub, treelet, or small tree to 5 m high; terminal thorns stout; leaves subcoriaceous or membranous,
not papillate on abaxial surface; pedicels more than 5 mm long.
5a. Leaves subcoriaceous to coriaceous; racemes 3- to 8-flowered; pedicels 10–15 mm long, glabrous;
enlarged lateral sepals elliptic; lateral petals 4–7 mm long, oblanceolate..........1.A. albicans
5b. Leaves membranous; racemes 2- to 4-flowered; pedicels 5–6 mm long, puberulent; enlarged
lateral sepals broadly oblong to almost circular; lateral petals 1.5–2 mm long, narrowly
oblong . ................................................ 5.A. guayaquilensis
2b. Leaves distinctly alternate.
6a. Shrub 0.8–1.5 m high; leaves 2.2–5
3 1–2.7 cm, papyraceous; flowers 5.5–6.4 mm long. . . . 2. A. brasiliensis
6b. Tree 3–14 m high; leaves more than 8.5
3 3.5 cm, coriaceous; flowers 10–15 mm long (but unknown in A.
dukei).
7a. Leaves 8.5–11.5
3 3.5–6.2 cm, 1.8–2.43 as long as wide, mostly ovate to broadly lanceolate;
peduncle of fruits ca. 0.5 cm long; Panama ................................. 4.A. dukei
7b. Leaves (10–)13–25
3 (3–)4–8 cm, 2.1–3.93 as long as wide, lanceolate to elliptic; peduncle of fruits
1–2.1 cm long; Brazilian Atlantic Forest . ............................. 6.A. pulcherrimus
1. Acanthocladus albicans A. W. Benn., in Eichler
& Urban, Fl. Bras. 13(3): 46. 1874. Polygala
bicolor Vell., Fl. Flumin. Icon. 7: 59. 1831, non
Polygala bicolor Kunth, in HBK, Nov. Gen. Sp.
(quarto ed.) 5: 394, tab. 507. 1823, nom. illeg.
Polygala bennettii Chodat, Me
´
m. Soc. Phys.
Gene
`
ve 30(8): 113. 1889, nom. superfl. Polygala
albicans (A. W. Benn.) Grondona, Darwiniana
8(2–3): 291. 1948. TYPE: Vellozo 7: tab. 59.
1827 (lectotype, designated by Marques [1984:
7]). Figure 1.
Polygala albicans (A. W. Benn.) Grondona var. caracaensis
Glaz. ex Marques, Rodrigue
´
sia 36(60): 7. 1984, as
carac¸aensis, syn. nov. TYPE: Brazil. Minas Gerais:
‘‘Entre Inficionado et Carac¸a,’’ 1885 (fl.), Glaziou
14493 (holotype, B not seen; isotypes, G not seen, G
photo at G, K, P).
Polygala albicans (A. W. Benn.) Grondona var. silvae
Marques, Rodrigue
´
sia 36(60): 7. 1984, syn. nov. TYPE:
Brazil. Goia
´
s: Rio Araguaia, Rio Coco, margem
esquerda, 15 Aug. 1978 (fl.), N. T. Silva 4830
(holotype, MG; isotype, RB).
Distribution and habitat. Acanthocladus albicans
is the most widespread species of the genus. It occurs
mainly in dry forest and shrubby caatinga of north-
eastern Brazil, ranging southward in semideciduous
forests in the states of Minas Gerais and Rio de Janeiro,
southeastern Brazil, and in some enclaves of dry forest
in the state of Goia
´
s and the central Brazilian plateau
(extending to the dry forest within the boundaries of the
Chaco dominium in southeastern Bolivia and north-
eastern Argentina and Paraguay) (Fig. 1).
Discussion. Marques (1984) separated Acantho-
cladus albicans into three varieties. We find that her
318 Novon

characters for distinguishing the varieties overlap. In
addition, these varieties can occur sympatrically
across the species range. Taking into account its
widespread geographical distribution in South Amer-
ica, A. albicans seems to constitute a single species
displaying great variation in its leaf morphology
(Fig. 1). Therefore, we do not accept here the varieties
proposed by Marques (1984). Acanthocladus albicans
closely resembles A. colombianus Aymard & J. F. B.
Pastore and A. guayaquilensis in leaf morphology and
petal size, but can be distinguished by the combina-
tion of leaves subcoriaceous to coriaceous (vs. hardly
Figure 1. Geographical distribution map for the Acanthocladus albicans complex with variation of leaf morphology
throughout their range within the Neotropical seasonally dry tropical forest (SDTF) dominium (light gray): A. albicans (
N
), A.
colombianus (m), and A. guayaquilensis (&). The leaf outlines are from: 1. T. S. Guedes 486; 2. F. B. Ramalho 103; 3. K. B.
Strier 1232; 4. L. C. Giordano et al. 1404; 5. M. G. Bovini et al. 479; 6. M. C. Marques 198; 7. E. Zardini & P. Aquino 34730; 8.
N. T. Silva 4830 (type, Polygala albicans var. silvae); 9. M. L. Fonseca 2973 (A. albicans); 10. X. Cornejo & C. Bonifaz 6028
(type, A. guayaquilensis); 11. B. Maguire & C. K. Maguire 44019 (type, A. colombianus).
Volume 20, Number 3 Pastore et al. 319
2010 Synopsis of Acanthocladus (Polygalaceae)

coriaceous in A. colombianus and membranous in A.
guayaquilensis) and not papillate on the abaxial
surface (vs. papillate in A. colombianus), pedicels
10–15 mm long (vs. 4–5 mm long in A. colombianus
and 5–6 mm long in A. guayaquilensis), enlarged
lateral sepals elliptic (vs. oblong in A. colombianus
and broadly oblong to almost circular in A. guaya-
quilensis), and oblanceolate, 4–7 mm long lateral
petals (vs. oblong, 3–4 mm long in A. colombianus and
narrowly oblong, 1.5–2 mm long in A. guayaquilensis).
Although Polygala bicolor Vell. is the oldest name
for Acanthocladus albicans, it is a later homonym of P.
bicolor Kunth. Following Article 53.1 of the Interna-
tional Code of Botanical Nomenclature (ICBN;
McNeill et al., 2006), the name P. bicolor Vell. is
illegitimate and, therefore, its epithet does not have
priority when used in combination with the genus
Acanthocladus (Art. 45.3). Because A. albicans was
published as a substitute for P. bicolor, it must be
based on the same type collection (Art. 7.3). Polygala
bennettii Chodat (1889) was published as a replace-
ment name for A. albicans, although the epithet
albicans was available in Polygala and should have
been adopted (Grondona, 1948), rendering the name
P. bennettii nomenclaturally superfluous under Article
52.1. Marques (1984) designated the plate (Vellozo,
1827: tab. 59) as the lectotype of P. bicolor Vell., and
thus also the type of A. albicans and P. bennettii.
Nevertheless, Bernardi (2000) did not follow this
previous lectotypification and considered Glaziou
5820 as the type for P. albicans.
Additional specimens examined. (An asterisk [*] indi-
cates specimens mapped in Fig. 1.) ARGENTINA. Chaco:
P. Jørgensen 2091 (GH). Corrientes: San Cosme, A.
Krapovickas 13013 (MO); Itatı
´
, bank of Rı
´
o Parana
´
, T. M.
Pedersen 7080 (NY), T. Ibarrola 908 (NY); Corrientes, T.
Meyer 5893 (GH), L. R. Parodi 11939 (GH); Rı
´
o Parana
´
,
Puerto Gonza
´
lez, T. Ibarrola 758 (NY). Formosa: A.
Krapovickas & C. L. Cristo
´
bal 13072 (MO). BOLIVIA. La
Paz: Franz Tamayo, Parque Nac. Madidi, V. M. Torres et al.
208 (MO). Santa Cruz: A. Iba
´
n
˜
ez, Cotoca, Camino a Paurito,
G. Coimbra S. 694 (NY); 7 km SE of Comun. Don Lorenzo, M.
Nee 40190 (NY). BRAZIL. Bahia: Ibipeba, Faz. Sa
˜
o
Vicente, *F. B. Ramalho 103 (RB); Itaju do Colo
ˆ
nia a
Feirinha, T. N. Santos 404 (CEPEC); Utinga, J. E. M. Braza
˜
o
3 (RB). Ceara
´
: Serra do Bezouro, *T. N. Guedes 486 (NY,
RB). Espı
´
rito Santo: Santa Teresa, Va
´
rzea Alegre, V.
Demuner et al. 938 (RB). Goia
´
s: Rio Araguaia, Margem do
Rio Coco, N. T. Silva 4830 (NY, RB); Sa
˜
o Domingos, Gruta
de Terra Ronca, *M. L. Fonseca 2973 (CEN, IBGE, RB).
Minas Gerais: Caratinga, Est. Ecol. de Caratinga, *K. B.
Strier 1232, 1335 (NY); Serra da Carac¸a, Glaziou 14493 (B,
P). Paraı
´
ba: Mature
´
ia, M. F. Agra et al. 4416 (MO).
Pernambuco: Floresta, Reserva Biol. de Serra Negra, M. J.
N. Rodal 683 (RB). Rio de Janeiro: Marica
´
, Ponta do
Funda
˜
o, M. C. L. Ramos 1357 (RB); Parati, Parati-Mirim,
Ilha da Cotia, APA Cairuc¸u, *L. C. Giordano et al. 1404
(RB), *M. G. Bovini et al. 479 (RB); Parati, Praia de
Jabaquara, *M. C. Marques 198 (RB); Praia Grande, Morro
do Cavala
˜
o, Glaziou 5820 (K, MPU, P, US). PARAGUAY.
Alto Paraguay: L. Molas & V. Vera 1101 (MO). [Amam-
bay:] N. Paraguay, entre Rı
´
o Apa y Rı
´
o Aquidaban, K.
Fiebrig 4771, 5134 (GH). Central: Estero de Yapa
´
, Puerto
Guyrati, Villa Oliva, *E. Zardini & A. Aquino 34730 (RB);
Concepcio
´
n, E. Hassler 7293 (GH, NY). Presidente Hayes:
E. Zardini & L. Guerrero 40510 (MO).
2. Acanthocladus brasiliensis Klotzsch ex Hassk.,
Ann. Mus. Bot. Lugduno-Batavum 1: 184. 1864.
Mundia brasiliensis A. St.-Hil. & Moq., Ann. Soc.
Sci. Orle
´
ans 9: 56. 1828. Polygala klotzschii
Chodat, Me
´
m. Soc. Phys. Gene
`
ve 30(8): 114.
1889, non Polygala brasiliensis L., Mant. Pl. 1:
99. 1767. TYPE: Brazil. Sa
˜
o Paulo: prov. de
Saint-Paul, 1816 (fl.), A. Saint Hilaire C1 1061
(lectotype, designated here, P).
Distribution and habitat. Acanthocladus brasilien-
sis is markedly characterized by the shrubby habit
with very thorny branches, leaves small, alternate, and
papyraceous, and the inflorescences 1- to 3(4)-
flowered. It is found in the Brazilian states of Rio de
Janeiro, Sa
˜
o Paulo, Parana
´
, and Mato Grosso do Sul,
in areas of savannas and of disturbed forests
(Marques, 1984).
Discussion. Chodat (1889) in a broad delimitation
of Polygala, which included two Acanthocladus
species, could not use the epithet brasiliensis to make
a new combination in the genus Polygala because of
the precedence of P. brasiliensis L. We chose A. Saint
Hilaire C1 1061 (P #00647133) as lectotype because
it is undoubtedly part of the original materials used by
Saint-Hilaire and Moquin-Tandon (1828) and consists
of a representative and well-preserved specimen that
matches with the original description and illustration
of the species.
Additional specimens examined. BRAZIL. Mato Grosso
do Sul: Amambaı
´
, Dobereiner & Tokarnia 895 (RB).
Parana
´
: G. Hatschbach et al. 8767 (MBM, MO). Sa
˜
o Paulo:
prov. de Saint-Paul, A. Saint Hilaire C2 1261 (P), A. Saint
Hilaire s.n. (P); Braganc¸a Paulista, R. Mello-Silva et al. 372
(NY, RB, SPF); Campinas, Santa Elisa, H. F. Leita
˜
o F. & N.
Taroda 2613 (NY); Ibiu
´
na, bairro Sorocabuc¸u, ca. 8 km da
SP-250 NO Km 63, T. Yano & O. Yano 49 (RB, SP); Ipero
´
,
Faz. Ipanema, R. R. Rodrigues et al. 94 (RB); Jaguariu
´
na, J.
Mattos 9084 (RB, SP); Jundiaı
´
, 25 Sep. 1949, F. C. Hoehne
s.n. (NY, RB, SP); Limeira, pro
´
x. a Limeira, 25 Sep. 1951, F.
C. Hoehne s.n. (NY, RB, SPF); Monte Alegre-Amparo, M.
Kuhlmann 917 (RB, SP); Pilar do Sul, 5 km N da cidade, J.
Mattos 9215 (RB, SP); Santa Ba
´
rbara do Oeste, E edge of
city, on E side of hwy. just S of railroad, G. Eiten et al. 5712
(RB, SP); Sa
˜
o Paulo, Jardim Bota
ˆ
nico de Sa
˜
o Paulo, L.
Rodrigues 68 (GH, RB, SP); Sarapuı
´
, Rod. Raposo Tavares,
Km
157, Faz. Aterradinho, 10 Sep. 1989, E. S. Petty s.n.
(ESA, RB); Serra do Japı
´
, ca. 10 km SW of Jundiaı
´
, H. F.
Leita
˜
o F. et al. 3180 (NY); Sorocaba, pro
´
x. a Brigadeiro
Tobias, A. S. Grotta s.n. (RB); Teodoro Sampaio, Morro do
Diabo, S. Romaniuc-Neto et al. 1214 (RB, SP); Valinhos,
320 Novon

Serra dos Cocais, R. G. Udulutsch et al. 24 (HUEFS);
Vinhedo, Estac¸a
˜
o de tratamento de a
´
gua, 23 Sep. 1977, H.
Makino s.n. (RB, SP).
3. Acanthocladus colombianus Aymard & J. F. B.
Pastore, Caldasia 31(1): 14. 2009. TYPE:
Colombia. [Cundinamarca:] 16 km below Fusa-
gasuga
´
, semixeric tableland, 1200 m, 19 Aug.
1959 (fl., fr.), B. Maguire & C. K. Maguire 44019
(holotype, NY). Figure 1.
Distribution and habitat. This species is only
known from the type collection gathered in an area of
seasonally dry forest of the inter-Andean valley of
Cundinamarca Department, Colombia (Fig. 1), thus
representing the first record of the genus from the
Andes (Aymard & Pastore, 2009).
Discussion. Acanthocladus colombianus is very
closely related to A. albicans and A. guayaquilensis,
but it can be distinguished from both by an
arborescent habit ca. 15 m high, smaller to obsolete
terminal thorns, leaves that are rigidly coriaceous and
papillate on the abaxial surface, and flowers with
shorter pedicels (4–5 mm long vs. more than 5 mm
long).
4. Acanthocladus dukei (Barringer) J. F. B. Pastore
& D. B. O. S. Cardoso, comb. nov. Basionym:
Polygala dukei Barringer, Ann. Missouri Bot.
Gard. 70: 203. 1983. TYPE: Panama. Darie
´
n: the
Bolimina, s.d. (fr.), J. A. Duke & N. Brista 385
(holotype, US not seen, US photo at US).
Distribution and habitat. Acanthocladus dukei is
only known by the type collection and is the single
species of the genus found in Central America, where
it occurs in the tropical evergreen forest of Darie
´
n
Province.
Discussion. Acanthocladus dukei closely resem-
bles A. pulcherrimus (Kuhlm.) J. F. B. Pastore & D. B.
O. S. Cardoso based mainly on its alternate leaves, as
well as on the arborescent habit, with the branches not
ending in thorns, and a similar fruit size and shape.
Although the flowers of A. dukei are still unknown,
this species can be recognized by its fruits with a very
short, ca. 0.5-cm-long peduncle (vs. the peduncles 1–
2.1 cm long in A. pulcherrimus) and leaves that are
usually smaller, 8.5–11.5
3 3.5–6.2 cm, and ovate to
broadly lanceolate (vs. leaves 13–23
3 4–8 cm,
lanceolate to elliptic in A. pulcherrimus).
5. Acanthocladus guayaquilensis B. Eriksen & B.
Sta
˚
hl, Fl. Ecuador 65: 7. 2000. TYPE: Ecuador.
Loja: Bosque Petrificado Puyango, Quebrada El
Chirimoyo, 03u539S, 80u049W, 17 Feb. 1998
(fl.), X. Cornejo & C. Bonifaz 6028 (holotype,
GUAY not seen; isotypes, GB not seen, MO, NY).
Figure 1.
Discussion. This species can be diagnosed by the
combination of membranous leaves and few-flowered
racemes, these flowers borne on short (5–6 mm long),
puberulent pedicels, with enlarged lateral sepals
broadly oblong to almost circular and the lateral
petals narrowly oblong, 1.5–2 mm long. Acanthocladus
guayaquilensis is part of a species complex that
includes A. albicans and A. colombianus. Although
these species share several morphological characters,
their geographic range does not overlap. Acanthocla-
dus guayaquilensis is endemic to the dry forests of
Pacific coastal Ecuador. The geographic distribution
of this species complex on disjunct areas of dry
vegetation is in accordance with the distribution
pattern of several Neotropical plant species or groups
of closely related species that have been used to
define the Neotropical seasonally dry tropical forest
(SDTF) dominium (Pennington et al., 2000; Prado,
2000) as shown in Figure 1.
Additional specimens examined. ECUADOR. El Oro/
Loja: Bosque petrificado Puyango, Quebrada El Inca, X.
Cornejo & Cornejo 4088 (GB, GUAY, K, MO); Quebrada El
Chirimoyo, X. Cornejo & Cornejo 4103 (GB, GUAY, K, MO).
Guayas: Reserva Ecol. Manglares Churute, quebrada del
Cerro Cimalo
´
n, X. Cornejo & C. Bonifaz 5124 (GB, GUAY,
MO); Cordillera del Naranjo, hills NW of Salanguillo,
Valverde 1703 (MO).
6. Acanthocladus pulcherrimus (Kuhlm.) J. F. B.
Pastore & D. B. O. S. Cardoso, comb. nov.
Basionym: Polygala pulcherrima Kuhlm., Arq.
Inst. Biol. Veg. 2(1): 83. 1935. TYPE: Brazil.
Espı
´
rito Santo: Vale do Rio Doce, Lagoa
Juparana, 30 Mar. 1934 (fl.), J. G. Kuhlmann
101 (lectotype, designated here, RB 1685).
Discussion. Although Kuhlmann (1935) properly
typified this species, it is worthwhile to discuss its
complex history. First, Bentham (1837) published
Corytholobium macrophyllum Benth. within Fabaceae,
changing later (1867) its family placement to Poly-
galaceae (Bernardi, 2000). Then, Bennett (1874)
published Securidaca corytholobium Benth. ex A. W.
Bennett as a new name for C. macrophyllum in the
Polygalaceae, providing an illustration based on a
confusion of two different species and genera, and
citing three different specimens, Blanchet 2087,
Burchell 9733, and Poeppig 2826. According to
Article 7.3 of the ICBN (McNeill et al., 2006), S.
corytholobium must have the same type as C.
macrophyllum, i.e., Poeppig 2826. Furthermore, the
Volume 20, Number 3 Pastore et al. 321
2010 Synopsis of Acanthocladus (Polygalaceae)

other species in Bennett’s illustration, representing
the collection Blanchet 2087, was later described as
Polygala pulcherrima by Kuhlmann (1935), who chose
different type collections (Kuhlmann 101 and Velho
s.n.), possibly to avoid even more confusion. We chose
Kuhlmann 101 as lectotype because it is better
preserved and also the first collection cited in the
protologue.
Acanthocladus pulcherrimus together with A. dukei
and A. santosii are the only species of the genus that
do not have thorny branches. Acanthocladus pulcher-
rimus is distinguished by the combination of its
remarkably large leaves, sometimes reaching 25 cm
long (vs. 8.5–11.5 cm long in A. dukei), and its
congested racemes, resembling fasciculate umbels
(vs. flowers in racemes with a well-developed axis in
A. santosii). It occurs in the Atlantic rainforest and
matas de tabuleiro of the states of Bahia, Espı
´
rito
Santo, Minas Gerais, and Rio de Janeiro.
Additional specimens examined. BRAZIL. Bahia: Ad
Ripas, Blanchet 2087 (BR, K); Ilhe
´
us, area do CEPEC, Km
22, rod. Ilhe
´
us–Itabuna, J. L. Hage & T. S. Santos 1766
(CEPEC, HUEFS, RB); Una, Faz. Sa
˜
o Rafael, R. S. Pinheiro
313 (CVRD, NY); Taboquinhas, T. S. Santos 1773 (NY).
Espı
´
rito Santo: Boa Esperanc¸a, L. Kollmann et al. 10204
(MBML); Ibirac¸u, prox. da estrada 101, Linhares, Reserva
Nat. da CVRD, D. A. Folli 4679 (CVRD); Linhares, Bananal,
P. P. P. Velho s.n. (R not seen, RB 19063); Linhares, Km 10
da rod. a Bananal lado N, T. S. Santos 2017 (CEPEC, RB);
Pedro Cana
´
rio, Faz. Sa
˜
o Joaquim, G. Martinelli et al. 11847
(NY, RB); Santa Leopoldina, Santa Lu
´
cia, L. Kollmann et al.
4060 (MBML, RB). Minas Gerais: Itueta, E. Tameira
˜
o-Neto
2464 (HUEFS). Rio de Janeiro: Sa
˜
o Joa
˜
o da Barra,
Guaxindiba, Faz. Sa
˜
o Pedro, H. C. Lima et al. 5222 (RB).
7. Acanthocladus santosii (Wurdack) J. F. B.
Pastore & D. B. O. S. Cardoso, comb. nov.
Basionym: Polygala santosii Wurdack, Bradea 3:
17. 1979. TYPE: Brazil. Bahia: Km 36 da Rod.
BR 101, de Texeira de Freitas a
`
Itamaraju
´
, 16
Aug. 1972 (fl.), T. S. Santos 2392 (holotype,
CEPEC; isotypes, RB, US not seen, US photo at
US). Figure 2.
Distribution and habitat. Acanthocladus santosii
is putatively endemic in southern Bahia and northern
Espı
´
rito Santo, an important region of the Atlantic
forest known for its endemic taxa and deserving
special attention for its conservation (Thomas et al.,
1998).
Discussion. Wurdack (1979) in his original de-
scription of Polygala santosii noted its morphological
resemblance to P. pulcherrima [5 Acanthocladus
pulcherrimus (Kuhlm.) J. F. B. Pastore & D. B. O. S.
Cardoso], but did not assign P. santosii to any section
of Polygala. In the most recent revision of the
Brazilian Acanthocladus species by Marques (1984),
as well as in Bernardi’s (2000) account of Polygala, A.
santosii was overlooked or perhaps deliberately
excluded from Polygala sect. Acanthocladus due to
its noticeably different inflorescence, which is an
elongate raceme. We here suggest that racemes in A.
santosii do not significantly differ from the inflores-
cences found in the remaining species of the genus,
except for a more conspicuous elongation of the fertile
internodes and axis. The other characters that lead us
to place P. santosii within Acanthocladus without
hesitation include the caducous sepals in fruit and the
morphology of the flower, fruit, and seed. Acantho-
cladus santosii is herein illustrated for the first time
(Fig. 2).
Additional specimens examined. BRAZIL. Bahia: Itagi-
mirim, Faz. Benfica, M. M. Santos & J. C. A. Lima 137 (HRB,
RB); Porto Seguro, Parque Nac. de Monte Pascoal, W. W.
Thomas 11232 (HUEFS, NY), 11351 (CEPEC, HUEFS, NY).
Espı
´
rito Santo: Linhares, Vale do Rio Doce, T. S. Santos
947 (CEPEC, RB); Sooretama, Reserva Flor. de Sooretama,
D. Sucre 5437 (RB).
8. Acanthocladus scleroxylon (Ducke) B. Eriksen
& B. Sta
˚
hl, Fl. Ecuador 65: 6. 2000. Basionym:
Polygala scleroxylon Ducke, Trop. Woods 50: 35.
1937. TYPE: Brazil. Amazonas: Humayta
´
, betw.
Rio Madeira & Lago Paraiso, 26 June 1936 (fl.),
A. Ducke s.n. [315] (holotype, RB 29038;
isotypes, F not seen, F photo at F, GH, K, MG,
MO, NY, P, US not seen, US photo at US).
Discussion. Acanthocladus scleroxylon is the only
species of the genus occurring across the Amazon
Basin (Brazil, Ecuador, and Peru). It is morphologi-
cally close to A. albicans, but differs by the
combination of puberulent pedicels and longer
rudimentary petals, 2.5–3 mm long (vs. pedicels
glabrous and rudimentary petals 0.5–1.5 mm in A.
albicans), as well as the arboreal habit that can reach
25 m in height.
Additional specimens examined. PERU. Loreto: Que-
brada Sucursari, Gentry et al. 54305 (K, MO, NY). Madre de
Dios: Manu
´
, Rı
´
o Manu
´
, Cocha Cashu station, W. R. Foster
9559, 9681 (MO, NY). San Martı
´
n: Alto Rı
´
o Huallaga, Juan
Jui, Klug 3830, 4344 (K, NY).
Acknowledgments. We thank the curators of the
herbaria cited for making their specimens available
and Fabiana Filardi for providing digital images of
type materials housed at RB. We are grateful to Alex
Popovkin for reviewing the English text and to Carla
de Lima for the line drawings. Roy Gereau, Darie
´
n
Prado, and Victoria C. Hollowell are also acknowl-
edged for their helpful suggestions on the manuscript.
Funding was provided by Ph.D. grants from Coorde-
322 Novon

Figure 2. Acanthocladus santosii (Wurdack) J. F. B. Pastore & D. B. O. S. Cardoso. —A. Flowering branch. —B. Bract
dorsal face. —C. Bract ventral face. —D. External inferior sepal. —E. Internal sepal (wing). —F. Carina. —G. Androecium
and lateral petals. —H. Gynoecium. —I. Fruit. —J. Seed. —K. Detail of seed indumentum. Drawn by Carla de Lima from W.
W. Thomas et al. 11232 (HUEFS).
Volume 20, Number 3 Pastore et al. 323
2010 Synopsis of Acanthocladus (Polygalaceae)

nac¸a
˜
o de Aperfeic¸oamento de Pessoal de Nı
´
vel
Superior (CAPES) to J. F. B. Pastore and from
Conselho Nacional de Desenvolvimento Cientı
´
fico e
Tecnolo
´
gico (CNPq) to D. B. O. S. Cardoso (process
143116/2008-8).
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324 Novon