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The diversification of ecological roles and related adaptations in closely related species within a lineage is one of the most important processes linking plant evolution and ecology. Plant architecture offers a robust framework to study these processes as it can highlight how plant structure influences plant diversification and ecological strategies. We investigated a case of gradual evolution of branching architecture in spp. (Rubiaceae), forming a monophyletic group in New Caledonia that has diversified rapidly, predominantly in rainforest understory habitats. We used a transdisciplinary approach to depict architectural variations and revealed multiple evolutionary transitions from a branched (Stone's architectural model) to a monocaulous habit (Corner's architectural model), which involved the functional reduction of branches into inflorescences. We propose an integrative functional index that assesses branching incidence on functional traits influencing both assimilation and exploration functions. We showed that architectural transitions correlate with ecologically important functional traits. Variation in ecologically important traits among closely relatives, as supported by the architectural analysis, is suggestive of intense competition that favored divergence among locally coexisting species. We propose that Pleistocene climatic fluctuations causing expansion and contraction of rainforest could also have offered ecological opportunities for colonizers in addition to the process of divergent evolution.

In this study we investigate the large and diverse Rubiaceae-Gardenieae and closely related tribes Bertiereae, Coffeeae, Cremasporeae, Octotropideae, and Pavetteae. Some of the tribes or groups have been shown to be monophyletic and strongly supported, but the phylogeny of this large complex is still far from being satisfactorily elucidated particularly for Gardenieae, both in terms of intertribal relationships as well as tribal delimitations. We reconstruct the phylogeny of the complex using an extensive sampling of 108 genera and five plastid DNA regions. Phylogenetic relationships demonstrate that Gardenieae sensu Andreasen & Bremer is polyphyletic, asBurchellia, Didymosalpinx, Monosalpinx, andMantalaniaa re closer to Octot ropideae -Cremasporeae. In addition, Pavetteae and the investigated members of Aulacocalyceae are nested in a supported but partially unresolved Gardenieae-Pavetteae clade. Within this clade, several strongly supported groups are resolved: anAidiagroup, anAlibertiagroup, aGardeniagroup, Pavetteae includingPelagodendron, aPorterandiagroup, aRandiagroup, aRothmanniagroup (includingAulacocalyxandHeinsenia), aSherbourniagroup, and the two isolated generaMassulariaandSchumanniophyton. The latter genus presented a high rate of genetic substitutions, which resulted in perturbations of the phylogenetic reconstruction. A revised tribal circumscription is given for Gardenieae, theAlibertiagroup is recognized at tribal level as an emended Cordiereae, and a new tribe, Sherbournieae, is described to accommodate the members of theSherbourniagroup.

We performed molecular phylogenetic analyses of the Randia clade of the tribe Gardenieae using both plastid and nuclear DNA data. In the phylogenetic hypotheses presented, the African genera Calochone, Euclinia, Macrosphyra, Oligocodon, Pleiocoryne, and Preussiodora are resolved as a monophyletic group. Support is also found for a clade of the Neotropical genera Casasia, Randia, Rosenbergiodendron, Sphinctanthus, and Tocoyena. This Neotropical clade is resolved as sister group to the African clade in analyses of combined plastid and nuclear data. The genus Euclinia appears polyphyletic. The species described from Madagascar represent an independent lineage, the position of which is moreover found to be incongruent between datasets. Plastid and ribosomal DNA data support a sister–group relationship to the mainland African clade, whereas the low–copy nuclear gene Xdh supports a closer relationship to the Neotropical genera. The phylogenetic reconstructions also indicate that Casasia and Randia are not monophyletic as presently circumscribed. A taxonomic proposal is made for the recognition of the Malagasy taxon at generic level as Melanoxerus.

Randia brevituba is a new species of the Paranean region of Argentina and Paraguay. It differs from the closest species, R. ferox, which is sympatric, in having short corolla tubes of 4.7–5.4 mm in the pistillate flowers and 2.8–7.9 mm in the staminate flowers, calyx lobes varying in shape and size in the same pistillate flower, and globose fruits 14–17 mm long (versus corolla tubes of 25.0–27.0 and 22.6– 34.0 mm long, respectively, calyx lobes equal in shape and size, and fruit 3–5 cm and ovoid, ellipsoid or subglobose in R. ferox). We also discuss the taxonomic concept and geographic distribution of Randia armata, and conclude that it is markedly different from R. brevituba and the other species in the Southern Cone studied here, and moreover, that it does not occur in the Southern Cone. We provide a taxonomic key to distinguish the new species from other species of Randia in the Southern Cone of America.

Como parte de la revisión de Randia para Sudamérica, se discute la identidad de dos especies amazónicas del género. Basanacantha inermis, descripta para Amazonia y conocida solo por el material tipo, es aquí reconocida como parte de la circunscripción de Randia. El uso del epíteto inermis se encuentra bloqueado en este género por uno anterior (Randia inermis Sessé & Moc.), por lo tanto, se provee un nuevo nombre, R. adolphoduckei. Basanacantha wittii, también reconocida hasta el presente solo por el tipo, es aquí considerada como nuevo sinónimo de R. hondensis. Se elige un lectotipo para B. wittii y un neotipo para R. hondensis. Se presentan descripciones completas para Randia adolphoduckei y R. hondensis, incluyendo datos de su biología y distribución. Se provee una ilustración de R. adolphoduckei detallando sus aspectos principales. Se presenta también una clave de las especies que habitan la Amazonia brasileña.

The tribe Posoquerieae was recently described to include the genera Posoqueria Aubl. and Molopanthera Turcz. based on floral morphology, palynology, the presence of the pollen catapult mechanism, and molecular phylogenetic evidence. The floral morphology of these two genera was first recognized as unique in the Rubiaceae by Schumann. Both genera have stamens initially united into an ellipsoidal structure held at an oblique position, with the ventral stamen that springs forward when touched, while the two lateral stamens fold outward. Since their descriptions were published, Posoqueria and Molopanthera have been positioned in several distantly related tribes within the Rubiaceae. The close relationship between the two genera was only recently revealed by molecular phylogenetic studies. The taxonomic history of Posoqueria and Molopanthera is reviewed, and a general morphological comparison (particularly of stamen morphology and pollen catapult mechanism, and observations about pollination biology) of both genera is presented here. The pollen catapult mechanism of Molopanthera is described here in detail for the first time and concluded to be practically identical to that of Posoqueria.

A new species of Sphinctanthus from the Rio Doce Valley, Atlantic forest in the state of Minas Gerais, Brazil, is here described and illustrated. The species is peculiar within the genus by having placentation entirely parietal, while in the other species of Sphinctanthus the placentation is basally axial and distally parietal. In addition, despite its bright orange flowers (being a plant with high potential as an ornamental), it is only known from two collections from nearby localities, indicating that it is a rare and critically endangered species

A description of the defining characteristics of Gardenia (Rubiaceae) and a revision of the Philippine species distinguished mainly by calyx morphology are presented. A key to five species of Gardenia recognised for the Philippines, full descriptions and illustrations, and a list of names which should be excluded from Gardenia are given. Relevant Philippine names for which holotypes were not indicated or have been destroyed are lectotypified. Two new endemic species, Gardenia ornata K.M.Wong and G. vulcanica K.M.Wong, are described. Gardenia elata Ridl. and G. mutabilis Reinw. ex Blume are newly applied to Philippine species previously enumerated under other names. Gardenia pseudopsidium (Blanco) Fern.-Vill. is considered a doubtful name, to which some authors have referred the endemic G. barnesii Merr.

Randia lorenceana (Rubiaceae), una especie nueva del bosque mesófilo de montaña del estado de Guerrero, México, está descrita e ilustrada. La especie nueva es afín a R. matudae, pero difiere de esta por tener estípulas, pedúnculos y lóbulos del cáliz de tamaño mayor y porque los lóbulos de la corola, anteras e hipanto de la flor estaminada son de una talla menor, además de poseer bayas péndulas por el recurvamiento del pedúnculo. Randia lorenceana (Rubiaceae), a new species from the cloud forest in the state of Guerrero, Mexico, is described and illustrated. The new species is related to R. matudae, but it differs from that species in having larger stipules, peduncles and calyx lobes, smaller corolla lobes, anthers, and hypanthium in the staminate flowers, and distinctly pendulous fruits due the of the bending of the peduncles.

The taxonomic history of Porterandia (Rubiaceae) is reviewed. Its plant architecture and other morphological characteristics are compared with those of the related Atractocarpus and Bungarimba. Porterandia species are typically gynodioecious (and sometimes gynomonoecious), with sexual dimorphism in inflorescence form and flowers. Secondary pollen presentation in bisexual flowers is present. In a cladistic analysis using 34 morphological characters, Porterandia, Atractocarpus heterophyllus (type species of Atractocarpus) and Bungarimba were neatly polarised from Aidia, the outgroup. The 20 species of Porterandia in the analysis formed a well-supported monophyletic group, clearly delimited by primary and lower-order branches with terminal cymes in forks, stipules fused into a tube and with hairy inner surfaces, anisophyllous leaf pairs, corollas with stiff bristle-like hairs over the tube outer surface and adaxially hairy lobes. A revision enumerated 22 species of Porterandia, including a new species, P. dinghoui Zahid & K.M.Wong. Borneo, with 19 species, is the centre of diversity; outlying taxa appear to diverge from Bornean taxa in some characters; for example, Porterandia anisophylla and P. scortechinii (Sumatra, Malaya) are the only species with downward-pointing hairs on the corolla tubes (the rest have upward-pointing hairs), and P. celebica (Sulawesi) has atypical hood-like, fused (instead of free) inflorescence bracts. The northwest Borneo region has a significant species diversity and congregation. Extinction of Porterandia populations from heavily disturbed or open sites indicates that habitat conservation and the integrity of large forest patches and tree stands are critical.