Taxonomic notes on Leandra (Melastomataceae, Miconieae)

(Taxonomic notes on Leandra (Melastomataceae, Miconieae)). In this paper we propose 11 synonyms and six lectotypes for eastern Brazilian species of Leandra. Leandra urophylla and L. nutans are placed in the synonymy of L. acutiflora; Leandra atropurpurea in the synonymy of L. australis; Ossaea ramboi in the synonymy of L. catharinensis; Leandra pulchra in the synonymy of L. clidemioides; Leandra furfurella in the synonymy of L. cordigera; Leandra macrosepala in the synonymy of L. laevigata; Leandra dusenii in the synonymy of L. microphylla; Leandra dolichodons in the synonymy of L. penduliflora; Leandra dasytricha and L. mosenii in the synonymy of L. variabilis. We also propose lectotypes for L. australis, L. atropurpurea, L. cordigera, L. dusenii, L. laevigata, and L. pulchra.


Introduction
Leandra Raddi is one of the largest genera in the Melastomataceae, with about 250 accepted species (Melastomataceae.net 2007(Melastomataceae.net -2012) ) in tropical and subtropical America.As currently defined, the genus is polyphyletic, with three unrelated clades: two of them are respectively formed by former sections Tschudya Cogn.and Secundiflorae Cogn., while the third clade is mostly composed of species from the five remaining sections, the genus Pleiochiton A.Gray, and some species of Ossaea DC. and Clidemia D.Don (Martin et al. 2008).This last clade (Leandra sensu stricto, following Goldenberg et al. 2008) includes ca.75% of the total Leandra species (including its generotype), and is primarily distributed in the Atlantic Forest region of eastern Brazil.The last complete revision of the genus was published in the 19 th century (Cogniaux 1891), and not even a small part of it has been revised since then.Several arrangements have been adopted for treatments in regional floras (Wurdack 1962, 1973, 1980, Wurdack et al. 1993, Camargo et al. 2009, Souza & Baumgratz 2009), and a lot of revisional work remains to be done.
In this paper, we solve problems related to nomenclature and species limits of eastern Brazilian Leandra based on our own morphological studies, but primarily from discussions by previous works (Wurdack 1962, Camargo et al. 2009) and herbarium notes by John Wurdack.Most of the new synonyms are related to species described for Leandra section Chaetodon Cogn.that have a synonym in one of the other sections.Leandra section Chaetodon is defined by pseudolateral inflorescences (terminal when in bud and flowering and lateral when fruiting).Inflorescence position is one of the two characters traditionally used to circumscribe genera in the tribe Miconieae and great taxonomic importance has historically been placed on this character.Nonetheless, it has been demonstrated to be either prone to miscoding (Judd & Skean 1991) or to be highly homoplastic (Michelangeli et al. 2004, Goldenberg et al. 2008, Martin et al. 2008).

Results and Discussion
1. Leandra acutiflora (Naudin)  Cogniaux (1891) placed L. acutiflora in section Oxymeris, but included both L. nutans and L. urophylla in section Chaetodon.The position of the inflorescence was considered diagnostic for these sections (terminal in Oxymeris and transitioning from terminal to lateral in Chaetodon), but this character is highly variable among some species and not always evident on herbarium sheets lacking either flowering or fruiting material.Phylogenetic analyses showed that these sections are not monophyletic as previously discussed (Martin et al. 2008), confirming that this character is homoplastic.The types of L. nutans and L. urophylla share with L. acutiflora sparse, deciduous, minute dendritic trichomes, and leaves distinctly plinerved bearing white tufted domatia on the axils of the lateral nerves on the abaxial surface.There is some degree of variation in the external calyx teeth, from obscurely tuberculate in the type of L. nutans to ca. 1 mm long in the type of L. urophylla, with intermediate states in the type and also in several specimens currently identified as L. acutiflora.Leandra urophylla has been proposed to be distinguishable by leaves with caudate to acuminate apices, but these features are frequently found within the specimens from the whole complex.The synonymization of L. nutans under L. urophylla was suggested but not formally published by Wurdack (1962)  Cogniaux (1886) placed both L. australis and L. atropurpurea in the section Niangae, among the group with reduced internal calyx lobes.The diagnostic character was supposed to be a difference in leaf venation: 5-7 basal in L. australis versus 5 suprabasal in L. atropurpurea.Despite the fact that the types agree with this distinction, this species is very common in southern Brazil and adjacent areas, and shows a broad variation in leaf size, nerve number and the distance from the lateral nerves to the base (basal versus suprabasal).These variation is not consistently related to other morphological features or geographical range, and do not sustain two distinct species.The synonymization of L. atropurpurea under L. australis was suggested by Wurdack (1962).Brade (1957) did not provide any comment nor compared O. ramboi with any species of Ossaea or Leandra.In a taxonomic review of the Brazilian Ossaea this species was excluded from the treatment and the author suggested it belongs to Leandra, based on inflorescence characters (Souza 1998).Leandra catharinensis was assigned to section Chaetodon by Cogniaux (1891), which is defined by terminal inflorescences (when in bud and flowering) that become lateral (when fruiting).The type specimen of O. ramboi has clearly pseudolateral inflorescences and shares all other morphological features with L. catharinensis.This synonymization was previously suggested by Wurdack (1962) Leandra clidemioides can readily be recognized by stamens bearing a dorsal, erect appendage (Wurdack et al. 1993).Cogniaux (1886) was probably misled in describing L. pulchra because the type specimens bear only fruits and consequently he did not see stamens.Moreover, he mentioned that Leandra (Platycentrum) clidemioides should occur in French Guyana, Trinidad and in an unknown place in Brazil, being apparently unaware that this species also occurs in eastern Brazil.The types of L. pulchra have the same appressed trichomes on the branches, strongly 5-plinerved leaves, inflorescences with accessory branches and large, light-colored fruits of L. clidemioides, indicating that both must be synonymized.

Leandra catharinensis
Nevertheless, the publication provides a good picture of the type, along with drawings of one trichome and flower buds.These show exactly the same small stellate-furfuraceous indument, small, cordate leaves, and acute calyx teeth found in L. cordigera.The author did not compare the species to L. cordigera or to any other species in the genus, and was probably unaware of its existence.The holotype of L. cordigera was destroyed in Berlin, thus the US isotype was chosen here as the lectotype.
6. Leandra laevigata (Triana)   When describing L. macrosepala, Ule (1915) compared it with L. gracilis Cogn.and L. pulchra, mentioning that the long calyx external teeth would be a diagnostic character.The species was not assigned to any section, but the last two belong to Leandra section Oxymeris, while L. laevigata was assigned to Leandra section Chaetodon (Cogniaux 1891).It seems that Ule was misled either by the different sections (see discussion above) or perhaps was unaware of L. laevigata.Both types share the same glabrous and polished leaves and the conspicuous calyx external teeth.This synonymization was previously suggested by J.J. Wurdack on a herbarium note.The holotype of L. laevigata was destroyed in Berlin, thus the US isotype was chosen here as the lectotype.Cogniaux did not mention L. microphylla while describing L. dusenii (Wurdack 1970).He also seemed to be misled by placing these two species in different sections (see discussion under L. acutiflora): L. microphylla was placed in the terminal-flowered section Carassanae, while L. dusenii in the terminal/ lateral-flowered section Chaetodon.The inflorescences in both types and recent collections are terminal and scarcely conspicuous due to its reduced size.Cogniaux (1891Cogniaux ( , 1910) ) described 5-nerved leaves for L. dusenii, and 3-nerved leaves for L. microphylla, but the types of both show leaves with 3 nerves and a faint submarginal pair that stays between both character states previously mentioned.Apart from these features, the descriptions of both species are very similar.Additionally, both types were collected about 80 km from each other on grasslands in the Paraná State.Wurdack (1970) had already discussed the differences between these two species, based on fragments of the specimens in BR.According to him, specimens of L. microphylla should have a sparsely setulose torus, glabrous style and slightly longer stamens, while L. dusenii should have a glabrous torus, sparsely strigulose style and plump anthers.Wurdack (1970) mentioned some intermediate specimens that he hesitate to assign to one of these species, and concluded that he was not sure if these species were distinct.Following the same line, and based on the analysis of several specimens, Camargo et al. (2009)  Cogniaux (1886) placed both species in section Chaetodon and they appear together in the identification key.According to the key, L. penduliflora should have branched shoots, obovate-oblong leaves and external calyx teeth as long as half the hypanthium length, while L. dolichodons should have simple, unbranched shoots, wide obovate leaves and external calyx teeth slightly shorter than the hypanthium length.Despite the fact that the types agree with this distinction, this species shows variation in leaf and external calyx teeth size, the last ranging from 0.9 to 1.5 mm long, which is equivalent to 35 to 85% of the hypanthium length.Moreover, the type localities are both situated in the "Quadrilátero Ferrífero" region of Minas Gerais state.Therefore, L. penduliflora might be identified by its glabrous (sometimes with trichomes restricted to the nerves on abaxial side), coriaceous leaves, with a conspicuous revolute margin, cuneate base, and slightly plinerved veins, the pseudolateral, glabrous inflorescence, and a hypanthium with a torus bearing dense indument.