This is the first phylogenetic analysis of the Megamexican Bromeliaceae genus Hechtia and includes 82.6 % of the known taxa. We used plastid (ycf1, rpl32-trnL intergenic spacer), and nuclear (PRK) DNA regions, as well as morphological characters. We generated 244 new sequences for a total of 62 taxa (including 12 species of the outgroup). Results of combined data using parsimony and Bayesian inference reveal the monophyly of Hechtia, as well as identify five well supported clades: (1) a clade (H. tillandsioides complex) as the sister group to the rest of Hechtia; (2) a clade including the species of the H. guatemalensis complex, distributed in Southern Megamexico; the remaining taxa of the genus are retained in a clade which consists of three well-supported clades; (3) the H. glomerata complex distributed in the Gulf of Mexico drainage; (4) a clade of two species (H. deceptrix and H. epigyna) that share an inferior ovary and are distributed north of the Tehuantepec Isthmus in the Sierra Madre Oriental; and (5) an internally poorly resolved clade with the remaining species containing several well-supported, geographically restricted clades. At this time it is uncertain what part of Megamexico was first invaded by the ancestor of Hechtia. Regardless, it becomes clear that from the original point of invasion in what is now Megamexico, it radiated into restricted geographical realms with secondary radiations occurring within them, which resulted in some recurrent particular evolutionary trends most likely associated with the invasion of dry, highly seasonal climates, or cooler areas subject to occasional frosts. Lateral inflorescences and flower morphology suggesting pollination syndromes other than melittophily (psychophily/trochilophily) have evolved more than once in Hechtia.

Full plastome sequences for land plants have become readily accessible thanks to the development of Next Generation Sequencing (NGS) techniques and powerful bioinformatic tools. Despite this vast amount of genomic data, some lineages remain understudied. Full plastome sequences from the highly diverse (>1,500 spp.) subfamily Tillandsioideae (Bromeliaceae, Poales) have been published for only three (i.e., Guzmania, Tillandsia, and Vriesea) out of 22 currently recognized genera. Here, we focus on core Tillandsioideae, a clade within subfamily Tillandsioideae, and explore the contribution of individual plastid markers and data categories to inform deep divergences of a plastome phylogeny. We generated 37 high quality plastome assemblies and performed a comparative analysis in terms of plastome structure, size, gene content and order, GC content, as well as number and type of repeat motifs. Using the obtained phylogenetic context, we reconstructed the evolution of these plastome attributes and assessed if significant shifts on the evolutionary traits’ rates have occurred in the evolution of the core Tillandsioideae. Our results agree with previously published phylogenetic hypotheses based on plastid data, providing stronger statistical support for some recalcitrant nodes. However, phylogenetic discordance with previously published nuclear marker-based hypotheses was found. Several plastid markers that have been consistently used to address phylogenetic relationships within Tillandsioideae were highly informative for the retrieved plastome phylogeny and further loci are here identified as promising additional markers for future studies. New lineage-specific plastome rearrangements were found to support recently adopted taxonomic groups, including large inversions, as well as expansions and contractions of the inverted repeats. Evolutionary trait rate shifts associated with changes in size and GC content of the plastome regions were found across the phylogeny of core Tillandsioideae.

1 Coconut is one of the most important tropical crops. It is threatened by Lethal yellowing disease. Production and selection by breeding require pollination, yet little is known of the pollination requirements and breeding system of this palm. 2 This study was carried out from 1999 to 2001 in coconut plantations represented by five coconut ecotypes commonly found in Mexico. It is the first study in the Neotropics on pollination and the breeding system of this palm. 3 Hymenoptera were the most numerous and diverse visitors to coconut flowers.The greatest period of insect abundance occurred during the rainy season (July to October). Insect abundance on the flowers correlated highly and positively with precipitation. 4 The abundance of visitors to pistillate flowers did not vary with season but there were significant differences between palm ecotypes; the most insect-visited flowers were of the Atlantic Tall ecotype. 5 The introduced honeybee (Apis mellifera) had the most appropriate foraging behaviour, visiting both pistillate and staminate flowers. These insects were probably the most efficient pollinators as they carry pollen on their ventral surface. Ants were present on flowers day and night but had no effect on pollination. 6 Pollination experiments indicated a mixed mating strategy: self-pollination by geitenogamy produced almost 19% of the fruit set, but cross-pollination (xenogamy) was the most important contribution (c. 30%). Anemophilous crosspollination only accounted for 10% of fruit set, whereas entomophily became the most important pollination mechanism under Yucatan conditions. 7 As coconut palm grows naturally on the oceanic strand in a wide variety of seasonal conditions of wind and rain, we suggest that they may have evolved pollination, breeding and mating systems that ensure fruit production under a wide variety of conditions, while maximizing the probability of cross-pollination.

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We performed a phylogenetic analysis using maximum parsimony and Bayesian inference of three plastid DNA markers and the external transcribed spacer (ETS) of nuclear ribosomal DNA to assess the species composition of the Tillandsia utriculata complex and their phylogenetic relationships, and to reconstruct patterns of character evolution and biogeography. The results showed that species of the T. utriculata complex are nested in a clade composed mainly of Mexican and Central American species of T. subgenus Tillandsia (Mexican Clade), and are organized in two lineages: the T. utriculata clade and the T. limbata clade. The ancestor of the core Mexican Clade was probably a T. utriculata-like epiphyte (Group II-type remote flowers and flexuous rachises). The T. utriculata clade is defined morphologically by the presence of acute petals. In this clade, there are two lineages: one of high-elevation, saxicolous, grey-leaved plants from the Mexican Plateau; and one which is more widespread and found from the Gulf of Mexico to Venezuela. The T. limbata clade probably arose in western Mesoamerica and is defined by rounded petals. These species are found mainly in tropical dry forests, but one species colonized wet environments of eastern Mesoamerica. Finally, analyses based on the ETS region allowed us to distinguish between T. utriculata and T. pringlei.