TAXON 56 (2) • May 2007: 439–452 Schütz Rodrigues & Tozzi • Taxonomic circumscription of Acosmium M O R PH O LO G Y Morphological analysis and re-examination of the taxonomic circumscription of Acosmium (Leguminosae, Papilionoideae, Sophoreae) Rodrigo Schütz Rodrigues1 & Ana Maria Goulart de Azevedo Tozzi2 1 2 Universidade Federal de Roraima, Centro de Ciências Biológicas e da Saúde, Departamento de Biologia, Campus do Paricarana, Av. Ene Garcez 2413, Boa Vista, RR, 69304-000 Brazil. rodrigo@dbio.ufrr.br (author for correspondence) Universidade Estadual de Campinas, Instituto de Biologia, Departamento de Botânica, CP 6109, Campinas, SP, 13083-970 Brazil Acosmium Schott is a Neotropical genus of ca. 17 species of trees with non-papilionoid, actinomorphic flowers. It has been included in the genistoid clade (Leguminosae, Papilionoideae) in recent phylogenetic analyses. A morphology-based cladistic analysis was performed to test the currently assumed monophyly of Acosmium, assess the validity of the infrageneric classification of Yakovlev, and detect synapomorphies and other diagnostic characters in Acosmium and related taxa. Thirty-four species representing ten genera of subfamily Papilionoideae were included in the analysis: all accepted species of the four sections of Acosmium together with species of Bowdichia, Clathrotropis, Diplotropis, Bolusanthus, Cadia, Poecilanthe, Cyclolobium, and Ormosia; two species of Luetzelburgia were selected as outgroups. The results do not support the monophyly of Acosmium; the species of this genus fall into three distinct, not closely related clades that correspond to the sections of Acosmium established by Yakovlev except for sect. Mesitis that merges into sect. Leptolobium. We propose: (1) recognizing a narrowly circumscribed genus Acosmium; (2) reinstating the generic name Leptolobium Vogel, encompassing sections Leptolobium and Mesitis; and (3) segregating A. praeclarum (Sandwith) Yakovlev into a new genus, Guianodendron. The phylogenetic relevance of some new or neglected characters, especially from bud architecture, seed, and seedling morphology is emphasized. KEYWORDS: Acosmium, genistoid clade, Leguminosae, Papilionoideae, phylogeny, taxonomy INTRODUCTION Acosmium Schott (Leguminosae, Papilionoideae, Sophoreae) is a Neotropical genus comprising ca. 17 species (Pennington & al., 2005). One species ranges from Mexico to northwestern South America; all other species are exclusively South American with the majority being restricted to Brazil (Bridgewater & Stirton, 1997). Most species are small to medium-sized trees but some tropical forest species reach to 40 m in height (Pauwells & al., 1999). Acosmium is characterized by stamens inflexed in bud, bracts at the pedicel base, regular, actinomorphic flowers (with five distinct calyx lobes and five subequal petals), free stamens, an apical or subapical hilum and samaroid fruits (Yakovlev, 1969; Polhill, 1981). Due mainly to its non-papilionoid flowers with free stamens, Acosmium has been considered as a basally branching genus within Papilionoideae, more particularly as a member of the tribe Sophoreae (Polhill, 1981, 1994; Herendeen, 1995). However, phylogenetic studies based on DNA sequence data have indicated that the genus holds an intermediate position within the subfamily (e.g., Doyle & al., 1997, 2000; Kajita & al., 2001), placing it in the genistoid clade (Pennington & al., 2001; Wojciechowski & al., 2004). The genistoid legumes as currently circumscribed (Wojciechowski & al., 2004) comprise the tribes Genisteae, Euchresteae, Thermopsideae, Podalyrieae (including Liparieae), Crotalarieae, Brongniartieae, and some genera of Millettieae and Sophoreae such as Acosmium, Bolusanthus Harms, Bowdichia Kunth, Cadia Forssk., Clathrotropis Harms, Diplotropis Benth., Dicraeopetalum Harms, and probably Ormosia Jacks. (Pennington & al., 2001). Potentially derived characters of the genistoids include the basic chromosome number x = 9 and the presence of quinolizidine alkaloids (Pennington & al., 2001; van Wyk, 2003; Wojciechowski & al., 2004). In the most recent revision of Acosmium, Yakovlev (1969) recognized four sections distinguished by the relative length of calyx lobes to calyx tube, number of stamens, and the curvature of the radicle. Acosmium praeclarum (Sandwith) Yakovlev belongs to the monospecific A. sect. Praeclara Yakovlev, which is characterized by a reduced stamen number of five. The remaining sections have ten stamens; flowers with the calyx lobes shorter than the tube define A. sect. Acosmium while A. sect. Leptolobium 439 TAXON 56 (2) • May 2007: 439–452 Schütz Rodrigues & Tozzi • Taxonomic circumscription of Acosmium (Vogel) Yakovlev and A. sect. Mesitis (Vogel) Yakovlev both have calyx lobes equaling or longer than the tube, the former with a straight radicle and the latter with a curved one (Yakovlev, 1969). Yakovlev (1969) synonymized the African genus Dicraeopetalum Harms under Acosmium, placing D. stipulare Harms in sect. Mesitis. However, a few years later he (Yakovlev, 1977) re-established Dicraeopetalum and included Lovanafia M. Peltier as a synonym. Recent cladistic analyses have confirmed Dicraeopetalum as a genus distinct from Acosmium (Pennington & al., 2001). Only species belonging to Acosmium sect. Leptolobium have been sampled in phylogenetic analyses of Papilionoideae. Therefore, questions about the monophyly of Acosmium as well as the relationships among its sections have not been addressed in prior analyses. In the trnL sequence analyses of Pennington & al. (2000, 2001) two species of Acosmium [A. panamense (Benth.) Yakovlev, A. subelegans (Mohlenbr.) Yakovlev], both from sect. Leptolobium, formed a highly supported clade with Bowdichia. This clade has been confirmed by Wojciechowski & al. (2004), whose matK phylogeny provided strong evidence for a sister relationship between Acosmium + Bowdichia and Diplotropis. Lavin & al. (2005) estimated a 29.5 ± 5.8 Ma age for the clade Diplotropis + Acosmium [sect. Leptolobium] + Bowdichia clade and a 12.8 ± 4.8 Ma age for the Acosmium [sect. Leptolobium] + Bowdichia clade. Within genistoid legumes, relationships among the mainly tropical Sophoreae are still poorly known in comparison with other, mostly temperate tribes (van Wyk, 2003). Neotropical sophoroid genera have not yet been the targets of phylogenetic studies to evaluate infrageneric relationships. With this in mind, we performed a cladistic analysis of Acosmium based on morphological data to (1) test the monophyly of the genus, (2) compare the results with the infrageneric classification of Yakovlev (1969), and (3) detect synapomorphies and other diagnostic characters for Acosmium and related taxa. MATERIALS AND METHODS Sampling and ingroup delimitation. — Thirtyfour taxa representing ten papilionoid genera were morphologically studied. We selected genera in which seedling morphology and pollen data were available for at least one species. All Acosmium taxa accepted by the authors belonging to the four sections sensu Yakovlev (1969), excluding Dicraeopetalum, were included. Species of eight genera assigned to the genistoid clade in previous molecular phylogenetic analyses (Pennington & al., 2001; Wojciechowski, 2003; Wojciechowski & al., 2004) were sampled: (1) from tribe Sophoreae three neotropical genera Bowdichia, Clathrotropis and Diplotropis, and the two 440 African Bolusanthus and Cadia (largely Madagascan), (2) from tribe Brongniartieae the genera Poecilanthe Benth. and Cyclolobium Benth. We also included species of Ormosia (Sophoreae), a pantropical genus whose position within the genistoid clade has been detected in some analyses (e.g., Pennington & al., 2001) but was not confirmed by Wojciechowski & al. (2004). Because relationships between genistoids and other major clades of Papilionoideae remain uncertain (Wojciechowski, 2003; Wojciechowski & al., 2004), we selected as outgroups two species of Luetzelburgia Harms, a genus that has been included in the vataireoid clade (Mansano & al., 2004; Wojciechowski & al., 2004). Characters and data sources. — Morphological data were based on analysis of herbarium specimens (Appendix 1) and on literature. For each terminal taxon 60 characters were scored (Appendix 2, Figs. 1–3). We were able to examine flowers and fruits from specimens of almost all taxa. For Bolusanthus speciosus Harms, Cadia pubescens Boj. ex Baker and C. purpurea (Picc.) Ait. all data were taken from literature (Hutchinson, 1964; van der Maesen, 1970; Polhill, 1981); for Clathrotropis macrocarpa Ducke floral features were obtained from Ducke (1932). Pollen characters were obtained from Ferguson & al. (1994); seedling morphology data from Polhill (1981), Polak (1992), Rodrigues (2005), and Rodrigues & Tozzi (in press a, b). Terminology for fruits and seeds follows Gunn (1981, 1991), Barroso & al. (1999), and Kirkbride & al. (2003); seedling morphology types follow Garwood (1996). Data were entered into a matrix using Nexus Data Editor (Page, 2001). The data matrix is presented in Appendix 3. Phylogenetic analyses. — Parsimony analyses were performed using Winclada 1.00.08 (Nixon, 2002). All characters were unordered and with equal weight to all changes, including uninformative characters (autapomorphies). A heuristic search was performed with the following settings: hold * (holding all trees that memory allows); mult*1000 (search with 1,000 replications); hold/100 (keeping 100 starting trees for each replication) and using, in effect, multiple tree bisection-reconnection (mult*max*). To assess the internal support of the clades we performed 1,000 bootstrap replicates (Felsenstein, 1985), with 30 search replicates (mult*30) and 10 starting trees per replication (hold/10) with tree bisection-reconnection in effect (max*). The changes in the character states were traced using WinClada 1.00.08 (Nixon, 2002). RESULTS The cladistic analysis yielded 578 equally most parsimonious trees of 134 steps (CI = 0.47, RI = 0.78), with 56 informative characters. The bootstrap (BS) strict consen- TAXON 56 (2) • May 2007: 439–452 Schütz Rodrigues & Tozzi • Taxonomic circumscription of Acosmium Fig. 1. Some reproductive characters used in a cladistic analysis of Acosmium. 1–7, A. sect. Acosmium; 1, calyx; 2, floral buds; 3, floral bud at anthesis (calyx removed), with petals not covering the other organs, stamens with slightly inflexed filaments and straight style; 4, standard petal; 5, wing petal; 6, keel petal; 7, flower in longitudinal section showing the subsessile ovary. 8–16, A. sect. Leptolobium plus Mesitis; 8, calyx; 9, floral buds; 10, detail of glands in bract axils; 11, floral bud at anthesis (calyx removed), with petals covering the other organs; 12, the same floral bud (corolla removed), showing the stamens with strongly inflexed filaments and curved style; 13 standard petal; 14, wing petal; 15, keel petal; 16, flower in longitudinal section showing the stipitate ovary; 17–22, A. sect. Praeclara; 17, calyx; 18, floral bud; 19, floral bud at anthesis (calyx, corolla and some stamens removed) showing the stamens with slightly inflexed filaments and curved style; 20, standard petal with inflexed auricles; 21, wing petal; 22, keel petal. 23–31, Bowdichia; 23, calyx; 24, floral bud, showing the curved hypanthium; 25, floral bud at anthesis (calyx, corolla and some stamens removed), showing the stamens with slightly inflexed filaments and curved style; 26, flower in longitudinal section (calyx, corolla and androecium removed), showing the stipitate ovary and the capitate stigma; 27 standard petal; 28, wing petal; 29, keel petal; 30, seed, showing the rim-aril; 31, embryo with a straight radicle. [1, Acosmium cardenasii (I.G. Vargas & al. 3339, NY); 2, 4–6, A. lentiscifolium (Schott s.n., NY); 3, A. diffusissimum (Harley & al. 27123, UEC); 7, A. lentiscifolium (Glaziou 7581, NY); 8, A. bijugum (Mori & al. 11419, NY); 9–10, A. dasycarpum (Schütz Rodrigues & Tozzi 1001, UEC); 11–12, A. subelegans (Schütz Rodrigues & Flores 993, UEC); 13–16, A. bijugum (Harley & Guedes 24108, NY); 17–19, A. praeclarum (Silva & Brazão 60916, MG); 20–22, A. praeclarum (Aitken in For. Dep. 2353, NY); 23–31, Bowdichia nitida (Zarucchi & al. 3063, RB)]. Bars = 1 mm (a), 1.5 mm (b), 2 mm (c), 3 mm (d) or 5 mm (e). Drawn by R.S. Rodrigues and Rogério Lupo (2–7, 9–16 and 20–22). 441 Schütz Rodrigues & Tozzi • Taxonomic circumscription of Acosmium TAXON 56 (2) • May 2007: 439–452 Fig. 2. Some reproductive characters used in a cladistic analysis of Acosmium. 1–8, Clathrotropis; 1, calyx; 2, floral bud; 3, floral bud at anthesis (calyx and corolla and some stamens removed), showing the stamens with slightly inflexed filaments and curved style; 4, flower in longitudinal section (calyx and corolla and some stamens removed) showing the subsessile ovary; 5, standard petal; 6, wing petal; 7, keel petal; 8, seed. 9–17, Diplotropis; 9, calyx; 10, floral bud, showing the curved hypanthium; 11, floral bud at anthesis (calyx and corolla removed), showing the stamens with slightly inflexed filaments and curved style; 12, flower in longitudinal section (calyx, corolla and androecium removed), showing the stipitate ovary; 13, standard petal with inflexed auricles; 14, wing petal; 15, keel petal; 16, seed; 17, detail of embryo apex showing a straight radicle. 18–24, Poecilanthe; 18, floral bud; 19, floral bud at anthesis (calyx lobes removed), with petals covering the other organs; 20, the same floral bud (calyx and corolla removed), showing the united stamens with straight filaments and style; 21, standard petal; 22, wing petal; 23, keel petal; 24, seed. 25–27, Cyclolobium; 25, floral bud; 26, floral bud at anthesis (calyx lobes removed), with petals covering the other organs; 27, the same floral bud (calyx and corolla removed), showing the stamens with slightly inflexed filaments and straight style. 28–38, Ormosia; 28, calyx; 29, floral bud; 30, flower; 31, flower (calyx, corolla and androecium removed), showing the gynoecium with lateral stigma; 32, flower in longitudinal section (calyx, corolla, androecium and part of gynoecium removed), showing the subsessile ovary; 33, standard petal; 34, wing petal; 35, keel petal; 36, seed; 37, embryo; 38, embryo. [1–7, Clathrotropis nitida (Ducke s.n., RB 23354); 8, C. nitida (Nelson ► 442 TAXON 56 (2) • May 2007: 439–452 Schütz Rodrigues & Tozzi • Taxonomic circumscription of Acosmium Fig. 3. Some seed and seedling characters of Acosmium. 1–2, A. sect. Acosmium; 1, seed, arrow indicating the lateral hilum with a persistent funicle; 2, embryo, arrow indicating the linear radicle perpendicular to length of the seed. 3–6, A. sect. Leptolobium plus Mesitis; 3, seed, subapical hilum with rim-aril (arrow); 4, embryo, arrow indicating the bulbose radicle parallel to length of the seed; 5, endosperm covering the embryo; 6, detail of a seedling (one cotyledon, part of the other cotyledon and basal region of hypocotyl removed), arrow indicating the intercotyledonary glands. [1–2, Acosmium cardenasii (Damasceno Jr. 3303, UEC); 3–5, A. nitens (Faria & Silva 621, RB); 6. A. brachystachyum (Schütz Rodrigues 1591, UEC)]. Bars = 0.5 mm (a), 1.5 mm (b), 2.5 mm (c) or 3 mm (d). Photographs by R.S. Rodrigues. sus tree, showing the most important synapomorphies for Acosmium and related taxa, is shown in Fig. 4. The morphological analysis did not support the monophyly of Acosmium; species of this genus fall into three distinct, not closely related clades. Species of sect. Acosmium comprise a very well supported clade (98% BS) that is sister to a clade with the two Cadia species included in the analysis. Together they form a well-supported clade (85% BS) sister to Bolusanthus speciosus (52% BS). Members of the remaining sections, on the other hand, are found in a weakly supported clade (53% BS) that also includes species of Bowdichia and Diplotropis. Within a subclade with 60% BS, A. praeclarum (sect. Praeclara) is sister to a clade with three Diplotropis species. The species of sections Leptolobium and Mesitis occur together in a moderately supported clade (83% BS) sister to a clade with two Bowdichia species (although this relationship has only 59% BS). DISCUSSION Our morphological analysis confirms some phylogenetic relationships within the genistoid legumes already recognized by DNA sequence studies, such as those be- tween Acosmium (p.p.), Bowdichia and Diplotropis (Pennington & al., 2000, 2001; Wojciechowski & al., 2004) and between Cyclolobium and Poecilanthe (Crisp & al., 2000; Pennington & al. 2001; Hu & al., 2002). However, the dataset did not permit illumination of some suprageneric relationships within genistoids such as the relative placement of Brongniartieae taxa (Wojciechowski & al., 2004), or clarify the positions of Ormosia and Clathrotropis, which is beyond the scope of this study. With respect to Acosmium, sectional classification has been traditionally based mainly on the relative length between calyx lobes and calyx tube, the curvature of the radicle (Bentham, 1865; Mohlenbrock, 1963 [both under Sweetia Spreng.]), and the number of stamens (Yakovlev, 1969). In this study, we detected three distinct clades in Acosmium that correspond to the sections recognized by Yakovlev (1969), except for sect. Mesitis which merged into sect. Leptolobium. In contrast to previous works which utilized a limited number of characters, the three Acosmium groups recognized here are defined on the basis of several vegetative and reproductive features (Table 1), including some new or neglected ones. Striking differences among sections Acosmium, Leptolobium plus Mesitis, and Praeclara in bud architecture as well as in seed and seedling morphology provided several informa- ► 1255, RB); 9–10, 12–15, Diplotropis purpurea (Gentry & al. 60835, RB); 11, D. racemosa (Ducke s.n., RB 11443); 16–17, D. purpurea (Rosa & al. 4512, RB); 18, Poecilanthe amazonica (Benson & Stubbline s.n., UEC 25140); 19–24, P. parviflora (Schütz Rodrigues & Flores 1582, UEC); 25–27, Cyclolobium brasiliense (Goes & Kirizawa s.n., UEC 93038); 28–35, Ormosia excelsa (Ducke s.n., RB 5095); 36, O. paraensis (Kuhlmann s.n., RB 17115); 37, O. flava (Ducke 1721, RB); 38, O. excelsa (Prance & al. 11558, RB)]. Bars = 0.5 mm (a), 1 mm (b), 2 mm (c), 3 mm (d), 5 mm (e) or 10 mm (f). Drawn by R.S. Rodrigues. 443 Schütz Rodrigues & Tozzi • Taxonomic circumscription of Acosmium TAXON 56 (2) • May 2007: 439–452 Fig. 4. Bootstrap consensus tree of a morphological cladistic analysis of Acosmium. The four sections of Acosmium (sensu Yakovlev, 1969), are highlighted (bold) on the tree. Only bootstrap values > 50% are indicated. The most important synapomorphies for Acosmium and related taxa are indicated on the tree. tive characters. Floral buds at anthesis may be ellipsoidal (Fig. 1.2) or globose to turbinate (Figs. 1.9 and 1.18), and have the petals covering (Fig. 1.11) or not (Fig. 1.3) the other floral organs; they may have a straight (Fig. 1.3) or curved (Fig. 1.12) style, as well as stamens with straight to slightly (Fig. 1.3) or strongly (Fig. 1.12) inflexed filaments. Although mature seeds were not available for Acosmium praeclarum, the seed cross-section, the concealment (Fig. 3.1) and position of the hilum (Figs. 3.1 and 3.3), presence of a rim-aril (Fig. 3.3), radicle shape, and its 444 relative position to the length of the seed (Figs. 3.2 and 3.4) differ conspicuously between sect. Acosmium and sect. Leptolobium plus Mesitis; of these seed characters, radicle shape has phylogenetic significance in this study. With respect to seedling morphology, it is possible to assign a species to one of the five seedling types on the basis of three cotyledon traits: emergence, position, and function (Garwood, 1996). Sections Acosmium, Leptolobium, and Mesitis have phanero-epigeal-foliaceous seedlings, while sect. Praeclara has crypto-hypogeal-reserve seedlings; TAXON 56 (2) • May 2007: 439–452 Schütz Rodrigues & Tozzi • Taxonomic circumscription of Acosmium Table 1. Morphological comparison of the sections of Acosmium sensu Yakovlev (1969). Characters A. sect. Acosmium A. sect. Leptolobium/ Mesitis A. sect. Praeclara Seedling morphological type Phanero-epigeal-foliaceous Phanero-epigeal-foliaceous Crypto-hypogeal-reserve Cotyledon nyctinasty presence Present Absent —a Intercotyledonary glands Absent Present — Hypocotyl shape Circular Quadrangular Circular Ratio hypocotyl/epicotyl length 8–20 : 1 1–4 : 1 — Stipule shape Lanceolate Linear to linear-lanceolate Ovate or elliptic, markedly striate Basal symmetry of leaflets Strongly asymmetrical Symmetrical Symmetrical Inflorescence position Exclusively axillary Terminal (axillary) Terminal (axillary) Bract persistence and presence of glands Caducous, without glands at axils Caducous, with glands at axils Persistent, with glands at axils Floral bud shape, petal coverage, filament inflexation, and style curvature at anthesis Elliptic, petals not covering the other organs, with slightly inflexed filaments and straight style Turbinate or globose, petals covering the other organs, with strongly inflexed filaments and curved style Turbinate or globose, petals covering the other organs, with slightly inflexed filaments and curved style Calyx tube and lobe length Subequal lobes, tube > lobes The two upper lobes larger and broader, tube < lobes Subequal lobes, tube < lobes Adaxial petal differentiation and auriculation Not differentiated, not auriculate Slightly differentiated or not, not auriculate Not differentiated, auriculate Stamen number 10 10 5 Ovary stipitation and ovule number Subsessile, 3–6-ovulate Stipitate, 2–6-ovulate Stipitate, 1(–2)-ovulate Seed shape, funicle presence, rim-aril presence, and radicle shape and curvature Flattened, funicle persistent, rim-aril absent, radicle linear, curved Compressed, funicle caducous, rim-aril present, radicle bulbose, straight (rarely curved) NDb a Dashes indicate inapplicable characters. ND indicates data not available. b in addition, the cross-sectional shape of the hypocotyl, presence of intercotyledonary glands (Fig. 3.6), ratio of hypocotyl length to epicotyl length, leaflet number of the eophyll at the first node, and leaflet and cotyledon nyctinasty supported some clades in this analysis. Our study demonstrated that sections Acosmium, Leptolobium plus Mesitis and Praeclara have structurally different flowers. The regular (or almost so) flowers of Acosmium s.l. are not homologous but result from evolution in distinct lineages. Pennington & al. (2000, 2001) proposed that many non-papilionoid flowers might be the product of reversals from papilionoid flowers. Although this is evident in the clade Bolusanthus and A. sect. Acosmium + Cadia, according to the character optimization, we are not able to visualize such reversals in the clade A. sect. Leptolobium and Mesitis + Bowdichia and A. sect. Praeclara + Diplotropis. Nevertheless, it is noteworthy that two groups with radiallly symmetrical flowers (sec- tions Leptolobium plus Mesitis, and Praeclara) formed distinct clades with the papilionoid-flowered Bowdichia and Diplotropis, respectively. More detailed studies examining flower ontogeny are needed to reveal ontogenetic similarities/differences among members of Neotropical genistoids and to compare them with other non-papilionoid taxa (e.g., Tucker 2002, 2003, Mansano & al., 2002). Acosmium sect. Acosmium. — This section is diagnosed by the synapomorphy of a very short epicotyl (ratio of hypocotyl length to epicotyl length 8–20 : 1). Some other seedling characters such as nyctinastic cotyledons and ascendant nyctinasty of leaflets could potentially diagnose this clade, but, due to missing data in some taxa, these characters might be ambiguous. Moreover, leaflets with an asymmetric base, ellipsoidal buds (Fig. 1.2), exclusively axillary inflorescences, absence of glands at bract and bracteole axils, calyx lobes shorter than the tube (Fig. 1.1), subsessile ovary (Fig. 1.7), flattened seeds 445 Schütz Rodrigues & Tozzi • Taxonomic circumscription of Acosmium without aril and with persistent funicle and linear radicle (Figs. 3.1–3.2), although homoplasious, help to distinguish sect. Acosmium from the remaining sections (Table 1). In this analysis, sect. Acosmium and the genus Cadia, both with non-papilionoid flowers (Figs. 1.4–1.6), formed a well-supported clade sister to the papilionoid-flowered Bolusanthus. Cadia and Bolusanthus have been included in the “core genistoids”, a clade that encompasses the majority of genistoid tribes (Crisp & al., 2000); and thus, our results were congruent with the topologies presented by Pennington & al. (2001) and Wojciechowski & al. (2004). Nevertheless, our finding of a relationship between sect. Acosmium and these paleotropical genera is unexpected, but interesting. This relationship has not been observed in any previous study; it might may be an artifact of poor sampling among genistoid taxa. The clade containing sect. Acosmium and Cadia presented the following synapomorphies: eophyll at first node 5-foliolate and linear radicle. Indeed, a linear radicle (Fig. 3.2) and absence of glands at the bract and bracteole axils are found only in sect. Acosmium among neotropical woody genistoids, which usually have short and bulbous radicles (Figs. 1.31, 2.8, 2.16–17, 2.24, 2.37–38 and 3.4) and glands clustered at bract and bracteole axils (Fig. 1.10), resembling colleters in shape and position (Thomas, 1991). In sect. Acosmium, the petals do not cover the stamens and the carpel in buds at anthesis (Fig. 1.3). A similar pattern was found by Tucker (2002, 2003) in Cadia purpurea. Tucker (2003) considered Cadia, as well as those taxa whose flowers appear radial at anthesis, neotenic in that they lack the final events in development that would express zygomorphy. Cadia is closely related to Podalyrieae, as supported by secondary chemistry (van Wyk, 2003) and DNA sequence data (Pennington & al., 2001). These taxa are restricted mainly to Africa, although Cadia and Calpurnia E. Mey. extend into the Arabian Peninsula and India, respectively (van der Maesen, 1970; Schutte & van Wyk, 1998). Despite several morphological differences, the lack of bracteoles in Cadia (van der Maesen, 1970) and most genera of Podalyrieae (Schutte & van Wyk, 1998) might be a significant character linking these taxa. Although sect. Acosmium has bracteoles, they are inconspicuous (0.3–0.5 mm long) and early caducous (Rodrigues, 2005), a fact that has also been verified in some bracteolate genera of Podalyrieae (Schutte & van Wyk, 1998). Moreover, the occurrence of a sessile or subsessile ovary and the predominance of axillary inflorescences in Podalyrieae might be taxonomically significant characters relating this tribe to Cadia and sect. Acosmium. A relationship between the South American Acosmium sect. Acosmium and genus Cadia raise an interesting question about the biogeography of Acosmium. Lavin & al. (2000) discussed several disjunct trans-Atlantic distributions in dalbergioid legumes, generally involving species 446 TAXON 56 (2) • May 2007: 439–452 with adaptations to seasonally dry or xeric vegetation. They (Lavin & al., 2000) inferred that legumes diversifying during the Tertiary in seasonally dry vegetation had the highest probability of subsequent radiation in both Africa and the neotropics, where similar vegetation types are widespread today. Recently, Schrire & al. (2005) presented a detailed discussion on the biogeography of Leguminosae, in which all genera could be assigned to at least one of four global biomes: the Succulent biome, the Grass biome, the Rainforest biome, and the Temperate biome. Acosmium sect. Acosmium and the genus Cadia share similar ecological preferences, occurring mainly in seasonally dry forest areas, corresponding to the Succulent biome of Schrire & al. (2005). It comprises a semi-arid, non-fire-adapted succulent-rich and grass-poor dry tropical forest, thicket and bushland biome, with a relatively small area and a highly fragmented distribution (Lavin & al., 2004; Schrire & al., 2005). The Succulent biome may represent the remnants of a persistent dry vegetation type that was linked, in the Tertiary, from circum-Amazonian South America through Central America, Mexico and Caribbean, along the Tethys Seaway to Africa, Arabia and India (Schrire & al., 2005). The disjunct distribution of A. sect. Acosmium and genus Cadia is compatible with the conclusions of Schrire & al. (2005) in which the Succulent biome is characterized by a predominance of amphiAtlantic disjunct taxa, but a more extensive sampling within genistoids would be desirable to support this geographical pattern. Acosmium sect. Leptolobium and Mesitis. — Our results do not support the separation of sections Leptolobium and Mesitis (sensu Yakovlev, 1969) as they form a moderately supported clade (83% BS). Curvature of the radicle has been used to distinguish sect. Leptolobium (straight radicle; see Fig. 3.4) from sect. Mesitis (curved radicle) after Vogel (1837), Bentham (1865) and Yakovlev (1969). However, Acosmium panamense (sect. Leptolobium) and A. brachystachyum (Benth.) Yakovlev (sect. Mesitis) have both straight and curved (oblique) radicles; this overlap blurs the recognition of two distinct sections. Polhill (1981) observed that inflexed stamens in floral buds were useful for distinguishing Acosmium from related genera in Sophoreae. Nevertheless, our morphological analysis shows that this trait is restricted to species of sections Leptolobium and Mesitis (Fig. 1.12); together with the adaxial petal slightly differentiated in shape and/or size from the other petals (Figs. 1.13–1.15), it constitutes the synapomorphies diagnosing this clade. The mode of organ packing of sections Leptolobium and Mesitis is a good example of “stuffing buds”, a term used by Endress (1994) to describe buds where the organs shape each other by mutual pressure, and thus attain irregular outlines. The slight differentiation of the adaxial petal, although mentioned for some species in early taxonomic works on Acos- TAXON 56 (2) • May 2007: 439–452 Schütz Rodrigues & Tozzi • Taxonomic circumscription of Acosmium mium (e.g., Vogel, 1837; Bentham, 1870; Harms, 1903), has not been discussed in subsequent studies (Mohlenbrock, 1963; Yakovlev, 1969), with the exception of Stirton & Aymard (1999). Acosmium dasycarpum (Vogel) Yakovlev, A. subelegans (sect. Leptolobium), and A. brachystachyum (sect. Mesitis) have adaxial petals more or less similar to the other petals. In contrast, in the remaining species of these two sections, the adaxial petal is different in form and/or size from the other petals. Within genistoids, Dicraeopetalum also presents radial flowers with a somewhat broader adaxial petal (Peltier, 1972). In the analysis of Pennington & al. (2001), Dicraeopetalum formed a clade with Bolusanthus and Platycelyphium Harms. The former two genera present recaulescent bracts that are also found in two other genera that are taxonomically related to Bolusanthus: Sakoanala R. Vig. and Neoharmsia R. Vig. (Polhill, 1981), which were not sampled by Pennington & al. (2001). The clade including Acosmium sect. Leptolobium and sect. Mesitis and genus Bowdichia is characterized by two seedling morphology synapomorphies, a hypocotyl that is quadrangular in cross-section and the presence of intercotyledonary glands (Fig. 3.6). Bowdichia is a South American genus comprising two species (Pennington & al., 2005), both sampled here (B. virgilioides Kunth, B. nitida Spruce ex Benth.). The Bowdichia clade is very well supported (99% BS) and has one synapomorphy from pollen morphology, the psilate tectum (an exine ornamentation, see Ferguson & al., 1994). Floral traits have traditionally been used to justify the close taxonomic relationship between Bowdichia and Diplotropis (e.g., Polhill, 1981) because they have papilionoid flowers with a curved hypanthium and crimped petals (Figs. 1.24, 1.27–29, 2.10 and 2.13–15). Nevertheless, in spite of a contrasting floral morphology between Bowdichia and Acosmium sections Leptolobium and Mesitis, their vegetative, seed and seedling similarities are notable. Moreover, tetracyclic Ormosia-type quinolizidine alkaloids are found in these taxa (van Wyk, 2003) and could be a phylogenetically relevant trait, although they are also known to occur in Ormosia and three genera of Brongniartieae. Sections Leptolobium and Mesitis and the genus Bowdichia formed a clade sister to Diplotropis and Acosmium sect. Praeclara (see below), supported by two synapomorphies: persistent bracts (sections Leptolobium and Mesitis have caducous bracts, a reversal according to the character optimization) and pollen with a finely reticulate tectum with irregularly shaped lumina (not isodiametric) about 0.5 µm on longest axis (with reversal in Bowdichia). Acosmium sect. Praeclara. — According to Yakovlev (1969), this section consists only of A. praeclarum. The species differs from all other Acosmium species by a set of dissonant characters: ovate to elliptic, markedly striate stipules, persistent bracts, petals with inflexed auricles (Figs. 1.20–22), and reduced stamen and ovule number (Table 1). Acosmium praeclarum formed a clade with Diplotropis, supported by one synapomorphy, the standard petal with carnose and inflexed auricles (Figs. 1.20 and 2.13). In addition, these taxa share crypto-hypogeal-reserve seedlings lacking cataphylls (see Polhill, 1981; Polak, 1992), in contrast to the phanero-epigeal-foliaceous seedlings found in the sections Leptolobium and Mesitis + Bowdichia clade. Moreover, A. praeclarum and the two species of Diplotropis sect. Racemosae H.C. Lima have leaflets with a papillate abaxial epidermis (Metcalfe & Chalk, 1957; Herendeen & Dilcher, 1990; Rodrigues & Tozzi, 2006). In Diplotropis sect. Racemosae (Lima, 1985), the flowers present five stamens and five staminodes (Fig. 2.11), while A. praeclarum has flowers with five stamens without staminodes (an autapomorphy); therefore, the trend in stamen reduction needs to be tested further. Despite sharing several vegetative and reproductive characters with Diplotropis, A. praeclarum does not fit within Diplotropis due mainly to the following traits: radial flowers with five subequal auriculate petals, straight hypanthium, five stamens and one (rarely two) ovule(s) (Rodrigues & Tozzi, 2006). Taxonomic circumscription of Acosmium. — This paper offers the first explicit demonstration that Acosmium does not correspond to a monophyletic group. Comparing the topology obtained from morphological data with those based on molecular data (Pennington & al., 2000, 2001; Wojciechowski, 2003; Wojciechowski & al., 2004) agreements are evident especially regarding relationships between Acosmium sect. Leptolobium plus Mesitis + Bowdichia and Diplotropis. The results presented here indicate that the current generic delimitation of Acosmium (Yakovlev, 1969) needs reconsideration. Hence, we propose: (1) adopting a narrowly circumscribed genus Acosmium, restricting it to sect. Acosmium; (2) reinstating the name Leptolobium Vogel (Rodrigues & Tozzi, unpubl. data), encompassing the species of sections Leptolobium and Mesitis; and (3) segregating A. praeclarum as a new genus, Guianodendron Sch. Rodr. & A.M.G. Azevedo (Rodrigues & Tozzi, 2006), considering that this species does not fit within any known papilionoid genera (sensu Lewis & al., 2005). ACKNOWLEDGMENTS We thank Andréia S. Flores for her encouragement and suggestions, and Rogério Lupo for preparing some illustrations. The curators of the cited herbaria are thanked for the loan of collections. We thank Enrique Forero, Gwilym Lewis, and an anonymous reviewer for many helpful comments and suggestions that improved this paper. The authors thank André 447 Schütz Rodrigues & Tozzi • Taxonomic circumscription of Acosmium Simões, Samantha Koehler, Vidal Mansano and Volker Bittrich for help and valuable advice throughout this work. This paper is a part of the Ph.D. thesis of R.S. Rodrigues prepared in the “Programa de Pós-Graduação em Biologia Vegetal”, Institute of Biology, Unicamp, and supported by a grant from the Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP proc. 00/09429-0). LITERATURE CITED Barroso, G.M., Morim, M.P., Peixoto, A.L. & Ichaso, C.L.F. 1999. Frutos e Sementes: Morfologia Aplicada à Sistemática de Dicotiledôneas. UFV, Viçosa. Bentham, G. 1865. On the Genera Sweetia, Sprengel, and Glycine, Linn., simultaneously published under the name of Leptolobium. J. Linn. Soc., Bot. 8: 259–267. Bentham, G. 1870. Leguminosae: Genera Sophoreis Addenda. Pp. 1–8 in: Martius, C.F.P. & Eichler, A.G. (eds.), Flora Brasiliensis, vol. 15, pt. 2. F. Fleischer, Lipsiae. Bridgewater, S.G.M. & Stirton, C.H. 1997. A morphological and biogeographic study of the Acosmium dasycarpum complex (Leguminosae: Papilionoideae, Sophoreae). Kew Bull. 52: 471–475. Crisp, M.D., Gilmore, S. & van Wyk, B.E. 2000. 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J. Bot. 91: 1846–1862. Yakovlev, G.P. 1969. A review of Sweetia and Acosmium. Notes Roy. Bot. Gard. Edinburgh 29: 347–355. Yakovlev, G.P. 1977. Notes on the taxonomy of the genera Baphiopsis Baker, Spirotropis Tul., Panurea Benth., and Dicraeopetalum Harms—Notulae systematicae. Novosti Sist. Vyssh. Rast. 14: 137–139. Appendix 1. Herbarium specimens of the taxa used in a cladistic analysis of Acosmium. Taxa Locality Voucher (collector with number, locality and herbarium acronyms) Acosmium sect. Acosmium A. lentiscifolium Schott A. lentiscifolium Schott A. lentiscifolium Schott A. diffusissimum (Mohlenbr.) Yakovlev A. diffusissimum (Mohlenbr.) Yakovlev A. diffusissimum (Mohlenbr.) Yakovlev A. cardenasii H.S. Irwin & Arroyo A. cardenasii H.S. Irwin & Arroyo A. cardenasii H.S. Irwin & Arroyo Brazil, Espírito Santo Brazil, Rio de Janeiro Brazil, Rio de Janeiro Brazil, Minas Gerais Brazil, Minas Gerais Brazil, Bahia Bolivia, Santa Cruz Bolivia, Santa Cruz Brazil, Mato Grosso do Sul D.A. Folli 1015 (CVRD) Schott s.n. (NY) M.A. Glaziou 7581 (BR, NY, RB) M. Magalhães 6040 (IAN, RB) R. Schütz Rodrigues & A.S. Flores 1567 (UEC) R.M. Harley & al. 27123 (NY) A. Gentry & al. 73954 (NY) I.G. Vargas & al. 3339 (NY) G. Damasceno Jr. 3303 (UEC) 449 Schütz Rodrigues & Tozzi • Taxonomic circumscription of Acosmium TAXON 56 (2) • May 2007: 439–452 Appendix 1. Continued. A. sect. Leptolobium (Vogel) Yakovlev A. dasycarpum (Vogel) Yakovlev A. dasycarpum (Vogel) Yakovlev A. glaziovianum (Harms) Yakovlev A. glaziovianum (Harms) Yakovlev A. nitens (Vogel) Yakovlev A. nitens (Vogel) Yakovlev A. nitens (Vogel) Yakovlev A. panamense (Benth.) Yakovlev A. panamense (Benth.) Yakovlev A. parvifolium (Harms) Yakovlev A. parvifolium (Harms) Yakovlev A. stirtonii Aymard & V. González A. stirtonii Aymard & V. González A. subelegans (Mohlenbr.) Yakovlev A. subelegans (Mohlenbr.) Yakovlev A. tenuifolium (Vogel) Yakovlev A. tenuifolium (Vogel) Yakovlev A. sect. Mesitis (Vogel) Yakovlev A. bijugum (Vogel) Yakovlev A. bijugum (Vogel) Yakovlev A. bijugum (Vogel) Yakovlev A. brachystachyum (Benth.) Yakovlev A. brachystachyum (Benth.) Yakovlev A. brachystachyum (Benth.) Yakovlev A. sect. Praeclara Yakovlev A. praeclarum (Sandwith) Yakovlev A. praeclarum (Sandwith) Yakovlev A. praeclarum (Sandwith) Yakovlev Bowdichia virgilioides Kunth B. virgilioides Kunth B. nitida Spruce ex Benth. B. nitida Spruce ex Benth. Diplotropis purpurea (Rich.) Amshoff D. purpurea (Rich.) Amshoff D. martiusii Benth. D. martiusii Benth. D. racemosa (Hoehne) Amshoff D. racemosa (Hoehne) Amshoff Clathrotropis macrocarpa Ducke C. macrocarpa Ducke C. nitida (Benth.) Harms C. nitida (Benth.) Harms C. nitida (Benth.) Harms Cyclolobium brasiliense Benth. C. brasiliense Benth. Ormosia excelsa Spruce ex Benth. O. excelsa Spruce ex Benth. O. arborea (Vell.) Harms O. arborea (Vell.) Harms O. flava (Ducke) Rudd O. flava (Ducke) Rudd O. paraensis Ducke O. paraensis Ducke O. stipularis Ducke O. stipularis Ducke Poecilanthe parviflora Benth. P. parviflora Benth. P. amazonica (Ducke) Ducke P. amazonica (Ducke) Ducke Luetzelburgia guaissara Toledo L. guaissara Toledo L. auriculata (Allemão) Ducke 450 Brazil, Minas Gerais Brazil, Minas Gerais Brazil, Distrito Federal Brazil, Minas Gerais Brazil, Amazonas Brazil, Amazonas Brazil, Pará Mexico, Oaxaca Mexico, Oaxaca Brazil, Piauí Brazil, Piauí Venezuela, Bolívar Brazil, Roraima Brazil, São Paulo Brazil, Mato Grosso do Sul Brazil, Bahia Brazil, Espírito Santo R. Schütz Rodrigues & A.M.G.A. Tozzi 1001 (UEC) R. Schütz Rodrigues & A.M.G.A. Tozzi 1015 (UEC) B.A.S. Pereira 458 (IBGE, RB) L. Roth 1856 (RB) J.L. Zarucchi & al. 3215 (NY) G.T. Prance & al. 11505 (MICH, NY) S.M. de Faria & Silva 621 (RB) M. Sousa & al. 5909 (MICH) C.E. Hughes 1308 (NY) R. Schütz Rodrigues & al. 1498 (UEC) E. Ule 7156 (HBG, L) C. Blanco 246 (NY) T.M. Sanaiotti 224 (UB) R. Schütz Rodrigues & A.S. Flores 993 (UEC) R. Schütz Rodrigues & A.S. Flores 1129 (UEC) R.P. Belém 3857 (F) M.S. Menandro 203 (CVRD) Brazil, Bahia Brazil, Bahia Brazil, Espírito Santo Brazil, Minas Gerais Brazil, Minas Gerais Brazil, São Paulo R.M. Harley & M.L. Guedes 24108 (NY) S.A. Mori & al. 11419 (NY) R. Schütz Rodrigues & al. 1600 (CVRD, UEC) H.S. Irwin & al. 22728 (C, NY, MICH, UB) R. Schütz Rodrigues & al. 1293 (UEC) R. Schütz Rodrigues 1591 (UEC) Brazil, Amazonas Guyana, Cuyini-Mazaruni Guyana, Essequibo River Brazil, Mato Grosso do Sul Brazil, Bahia Brazil, Amazonas Brazil, Pará Brazil, Pará Peru, Loreto Brazil, Amazonas Brazil, Amazonas Brazil, Pará Brazil, Pará Brazil, Amazonas Brazil, Roraima Brazil, Amazonas Venezuela, Amazonas Brazil, Amazonas Brazil, São Paulo Brazil, São Paulo Brazil, Amazonas Brazil, Pará Brazil, São Paulo Brazil, São Paulo Brazil, Pará Brazil, Pará Brazil, Mato Grosso Brazil, Mato Grosso Brazil, Pará Brazil, Amazonas Brazil, São Paulo Brazil, São Paulo Brazil, Amazonas Brazil, Amazonas Brazil, São Paulo Brazil, São Paulo Brazil, Piauí N.T. Silva & U. Brazão 60916 (MG, NY) N.Y. Sandwith 1109 (NY, U) Aitken in For. Dept. 2353 (NY) A.S. Flores 522 & R.Schütz Rodrigues (UEC) R. Schütz Rodrigues & al. 1329 (UEC) J.L. Zarucchi & al. 3063 (RB) A. Ducke s.n. (RB 11433) N.A. Rosa & al. 4512 (RB) A. Gentry & al. 60835 (RB) G.T. Prance & al. 3161 (RB) W. Rodrigues 8828 (RB) A. Ducke s.n. (RB 11443) N.T. Silva & C. Rosário 4992 (RB) A. Ducke s.n. (RB 24054) N.A. Rosa & R.L. Loureiro 361 (RB) B.W. Nelson 1255 (RB) B. Maguire & al. 36629 (RB) A. Ducke s.n. (RB 23354) M. Goes & M. Kirizawa s.n. (UEC 93038) D.A. Santin s.n. (UEC 30964) G.T. Prance & al. 11558 (RB) A. Ducke s.n. (RB 5095) F.C. Hoehne s.n. (UEC 84403) N. Figueiredo & R.R. Rodrigues s.n. (UEC 30258) A. Ducke s.n. (RB 17080) A. Ducke 1721 (RB) J.G. Kuhlmann s.n. (RB 17115) J.G. Kuhlmann & S. Jimbo 322 (RB) A. Ducke s.n. (RB 20365) A. Ducke s.n. (RB 23363) R. Schütz Rodrigues & A.S. Flores 1582 (UEC) O. Cesar 813 (HRCB, UEC) W.W. Benson & W.H. Stubbline s.n (UEC 25140) J.L. Zarucchi & al. 2968 (F) M. Kuhlmann 179 (UEC) L.A.F. Matthes 7329 (UEC) A.J. Castro s.n. (UEC 46090) TAXON 56 (2) • May 2007: 439–452 Schütz Rodrigues & Tozzi • Taxonomic circumscription of Acosmium Appendix 2. Morphological characters and character states used in a cladistic analysis of Acosmium. 1. Cotyledon emergence: phanerocotylar (0), cryptocotylar (1) 2. Cotyledon position: epigeal (0), hypogeal (1) 3. Cotyledon function: reserve absorption only (0), effective photosynthetic (foliaceous) (1) 4. Cataphylls at epicotyl: absent (0), present (1) 5. Hypocotyl cross-sectional shape: circular (0), quadrangular (1) 6. Intercotyledonary glands: absent (0), present (1) 7. Phyllotaxis of eophyll at first node: opposite (0), alternate (1) 8. Leaflet nyctinasty: downward nyctinastic movement of leaflets (0), forward-folding nyctinastic movement of leaflets (1) 9. Cotyledon nyctinasty: absent (0), present (1) 10. Leaflet number of the eophyll at first node: 1-foliolate (0), 3-foliolate (1), 5-foliolate (2) 11. Ratio of hypocotyl length to epicotyl length: 1–4 : 1 (0), 8–20: 1 (1) 12. Leaflet number of mature leaves: multifoliolate (0), 1foliolate (1) 13. Base of leaflets: symmetrical (0), asymmetrical (1) 14. Stipule shape: linear to linear-lanceolate (0), ovate, markedly striate (1) 15. Inflorescence position and type: terminal panicle, with some axillary racemes present at some nodes below the terminal inflorescence (0), exclusively axillary raceme (1) 16. Glands clustered at bract and bracteole axils: absent (0), present (1) 17. Position of bracts: at the base of pedicel (0), on pedicel [recaulescent bracts] (1) 18. Persistence of bracts: caducuos (0), generally persistent at fruiting (1) 19. Bract shape: ovate to triangular (0), linear to linear-lanceolate (1) 20. Bracteoles: present (0), absent (1) 21. Shape of floral bud: turbinate or globose, with rounded apex (0), ellipsoidal, with acute apex (1) 22. Petal coverage of floral bud at anthesis: petals cover the stamens and the carpel (0), petals do not cover the stamens and the carpel (1) 23. Style curvature of floral bud at anthesis: straight style (0), curved style (1) 24. Filament inflexation of floral bud at anthesis: stamens with straight or slightly inflexed filaments (0), stamens with strongly inflexed filaments (1) 25. Hypanthium curvature: straight (0), curved (1) 26. Petal color: blue/red (0), white/yellow (1) 27. Flower position: not pendent (0), pendent (1) 28. Adaxial petal (“standard petal”) differentiation: strongly differentiated from the other petals (0), slightly differentiated in shape and/or size from the other petals (1), not differentiated from the other petals (2) 29. Relative size and shape of calyx lobes: unequal lobes, the two upper lobes larger and broader than the others 30. 31. 32. 33. 34. 35. 36. 37. 38. 39. 40. 41. 42. 43. 44. 45. 46. 47. 48. 49. 50. 51. 52. 53. 54. 55. 56. 57. 58. 59. 60. (0), subequal lobes, the two upper lobes not larger and broader than the others (1) Ratio of calyx tube length to lobe length: tube > lobes (0), tube < lobes (1) Presence of carnose and inflexed auricles on adaxial petal (“standard petal”): absent (0), present (1) Presence of sculpturing on wings: without a conspicuous sculptured area (0), with a conspicuous sculptured area (1) Differentiation of wing and keel petals: not differentiated (0), differentiated (1) Presence of hood on keel petals: not hooded (0), hooded (1) Keel petals: free (0), connate (1) Presence of petal crimping, especially wing and keel petals: absent (0), present (1) Stamen number and presence of staminodes: 10 (0), 5 [plus 5 staminodes] (1), 5 [without staminodes] (2) Filament connation: filaments united at least to halfway (0), free (1) Presence of anther dimorphism: absent (0), present (1) Ovule number: 1(–2) ovule(s) (0), > 2 ovules (1) Ratio of stipe length to ovary length: 0–0.3 [ovary sessile to subsessile] (0), 0.45–1 [ovary stipitate] (1) Stigma position: terminal (0), lateral, introrse (1) Shape of stigma: punctiform (0), capitate (1) Dehiscence of fruits: indehiscent (0), dehiscent (1) Indehiscent fruit type: samara (0), samaroid legume (1), nut-like legume (2) Seed shape: not reniform (0), reniform (1) Shape of seed transection [ratio of seed width to seed diameter]: terete [1 : 1] to compressed [2 : 1] (0), flattened [> 4 : 1] (1) Pattern of seed coloration: monochrome (0), bicoloured (1) Hilum concealment: concealed by a persistent funicle (0), exposed (1) Hilum position according to seed length: lateral (0), apical or subapical (1) Presence of rim-aril: absent (0), present (1) Position of cotyledons in relation to fruit valves: parallel (0), transverse (1) Radicle position and curvature: oblique or perpendicular to length of the seed [“radicle curved”] (0), parallel to length of cotyledons [“radicle straight”] (1) Radicle shape: bulbose (0), linear (1) Presence of endosperm: absent (0), present (1) Pollen size [polar length]: < 25 µm (0), > 25 µm (1) Exine ornamentation: tectum evenly perforate/microperforate (0), finely reticulate with irregularly shaped lumina (not isodiametric) about 0.5 µm on longest axis (1) Exine ornamentation: tectum perforate (0), tectum psilate (1) Tectum thickness: thinner than infratectum (0), equal to or thicker than infratectum (1) Exine ornamentation: tectum perforate (0), sparsely perforate at least on poles, sometimes foveolate (1). 451 TAXON 56 (2) • May 2007: 439–452 Schütz Rodrigues & Tozzi • Taxonomic circumscription of Acosmium Appendix 3. Data matrix for a cladistic analysis of Acosmium. Characters Taxa 000000000111111111122222222223333333333444444444455555555556 123456789012345678901234567890123456789012345678901234567890 Luetzelburgia guaissara Luetzelburgia auriculata Poecilanthe parvifolia Poecilanthe amazonica Cyclolobium brasiliense Clathrotropis nitida Clathrotropis macrocarpa Ormosia excelsa Ormosia arborea Ormosia flava Ormosia paraensis Ormosia stipularis Bowdichia virgilioides Bowdichia nitida Diplotropis purpurea Diplotropis martiusii Diplotropis racemosa Acosmium lentiscifolium Acosmium diffusissimum Acosmium cardenasii Acosmium bijugum Acosmium brachystachyum Acosmium dasycarpum Acosmium glaziovianum Acosmium nitens Acosmium panamense Acosmium parvifolium Acosmium stirtonii Acosmium subelegans Acosmium tenuifolium Acosmium praeclarum Bolusanthus speciosus Cadia purpurea Cadia pubescens 0000000000000000000000000000000000000000000000000000000????? ???????????0000000000000000000000000000000000000000000000000 11-00010-0-000110000100001000101101000111001-0100100000????? ???????????100110000100000000101111000111001-0100100000????? 0000000000010011000010000000000110000001100010100000100????? ???????????001010000100000000001001001010001-0101010000????? 11-1000?-1-00?010000100000000001001001010001-010101000010000 11-?????-?-00001001000100000010100000101011020001111000????? 11-00000-0-000010010001000000101000001010111-0011111000????? ???????????000010010001001000001000001010111-000111000010011 11-0000?-0-000010010001000000101000001010111-0011111000????? ???????????000010010001000000101000001010111-000111100010011 001011100a000001011000101a0000001001010110101000111010110111 00?011????00000101100010100000001001010110101000111010110111 11-0001?-0-0000101000010100000100001010110001010110010001000 ???????????0000101000010100000100001010110002110110010001000 ???????????00111011000101000001000011101100010101100100????? 0010001111101010001011000102100000000101000010100000011????? 0010001112101010001011000102100000000101000010100000011????? 0010001112101010001011000102100000000101000010100000011????? 0010111000000001001000110101010000000101100010001010001????? 001011100a000001001000110102010000000101100010001110a01????? 0010110-0000000100100011010201000000010110001000111010101000 ???????????00001001000110101010000000101100010001110101????? 001011a00a00000100100011010101000000010110002000111010101000 00101?0?0?000001001000110101010000000101100010001110a0101000 ???????????00001001000110101010000000101100010001110101????? ???????????00001001000110101010000000101100010001110101????? 001011000000000100100011010201000000010110001000111010101000 ???????????00001001000110101010000000101100010001110101????0 11-0000?-1-0010101000010010210100000210010001??????????01000 00100?1??000100010001???00000101011001010011-000101000100000 00100?1??2000010000111000a121100000001010001-000101001100011 ???????????0001000011???00121000000001010001-0001010011????? Note: Characters and character states are listed in Appendix 2. Polymorphisms are indicated by “a” (0 + 1). Dashes indicate inapplicable characters; question marks indicate unknown states. 452