Recent debates on the number of plant species in the vast lowland rain forests of the Amazon have been based largely on model estimates, neglecting published checklists based on verified voucher data. Here we collate taxonomically verified checklists to present a list of seed plant species from lowland Amazon rain forests. Our list comprises 14,003 species, of which 6,727 are trees. These figures are similar to estimates derived from nonparametric ecological models, but they contrast strongly with predictions of much higher tree diversity derived from parametric models. Based on the known proportion of tree species in neotropical lowland rain forest communities as measured in complete plot censuses, and on overall estimates of seed plant diversity in Brazil and in the neotropics in general, it is more likely that tree diversity in the Amazon is closer to the lower estimates derived from nonparametric models. Much remains unknown about Amazonian plant diversity, but this taxonomically verified dataset provides a valid starting point for macroecological and evolutionary studies aimed at understanding the origin, evolution, and ecology of the exceptional biodiversity of Amazonian forests.Amazonia | floristics | rain forests | seed plants | species diversity

A phylogenetic analysis based on nuclear ITS and plastid trnK intron sequences confirms that Dahlgrenodendron, Sinopora, Triadodaphne, and Yasunia are members of the Cryptocarya group, as expected from morphology. Dahlgrenodendron from South Africa is sister to Aspidostemon from Madagascar. Triadodaphne inaequitepala is nested within Endiandra (both from Australasia), and Yasunia from South America is nested among South American Beilschmiedia species. Sinopora is a member of the Beilschmiedia clade, but its precise position is still uncertain. Among large genera of the group, Cryptocarya is clearly monophyletic, and Endiandra appears to be as well, if T. inaequitepala is included. Beilschmiedia is paraphyletic with respect to (at least) Potameia and Yasunia. Most wellsupported clades within genera are geographically homogeneous, except a clade including the Chilean Cryptocarya alba and two New Caledonian species. Both Beilschmiedia and Cryptocarya have reached the Americas more than once. Four-locular anthers are plesiomorphic in the Cryptocarya group; two-locular anthers have arisen by fusion of the two pollen sacs of a theca. In the plesiomorphic fruit type, the ovary is completely enclosed in receptacular tissue; a superior fruit, seated free on its pedicel, is a synapomorphy of the Beilschmiedia clade.

No abstract

Cinnamomum is among the largest genera of the Lauraceae, including species from tropical to temperate Asia and from tropical to subtropical America. However, previous studies indicated that Cinnamomum might not be monophyletic in its current circumscription. We therefore re‐investigated the genus and possible relatives with an increased taxon sample, particularly of the Neotropical species. Our results, based on sequences of the nuclear ITS region and the chloroplast spacers psbA‐trnH and trnG‐trnS, show that the Neotropical Cinnamomum species indeed do not form a monophyletic group with the Paleotropical species. Instead, the American species form a clade in which most species of the Neotropical genus Aiouea are nested within several subclades. According to the ITS data the Aiouea/Cinnamomum clade is sister to the likewise predominantly Neotropical Ocoteacomplex, rather than the two Paleotropical Cinnamomum clades. Therefore, Cinnamomum cannot be upheld in its cur‐rent circumscription. As the type C. verum, is from Asia, the Neotropical species need to be placed in a different genus. We decided to transfer them to Aiouea here, because this is the oldest generic name in the Aiouea/Cinnamomum clade, and the only character separating Aiouea from Neotropical Cinnamomum is the number of pollen sacs per anther (di‐ vs. tetrasporangiate), a feature that is known to be variable within several other genera as well. This transfer requires 42 new combinations and two nomina nova. In addition, six species described in the unpublished Ph.D. thesis of one of the authors (FLH) are validated in Aioueahere, and the only species of the genus Mocinnodaphne is transferred to Aiouea as well.

The genus Ocotea (Lauraceae) includes about 450 species, of which about 90% are Neotropical, while the rest is from Macaronesia, Africa and Madagascar. In this study we present the first complete chloroplast genome sequences of seven Ocotea species, six Neotropical and one from Macaronesia. Genome sizes range from 152,630 (O. porosa) to 152,685 bp (O. aciphylla). All seven plastomes contain a total of 131 (114 unique) genes, among which 87 (80 unique) encode proteins. The order of genes (if present) is the same in all Lauraceae examined so far. Two hypervariable loci were found in the LSC region (psbA-trnH, ycf2), three in the SSC region (ycf1, ndhH, trnL(UAG)-ndhF). The pairwise cp genomic alignment between the taxa showed that the LSC and SSC regions are more variable compared to the IR regions. The protein coding regions comprise 25,503–25,520 codons in the Ocotea plastomes examined. The most frequent amino acids encoded in the plastomes were leucine, isoleucine, and serine. SSRs were found to be more frequent in the two dioecious Neotropical Ocotea species than in the four bisexual species and the gynodioecious species examined (87 vs. 75–84 SSRs). A preliminary phylogenetic analysis based on 69 complete plastomes of Lauraceae species shows the seven Ocotea species as sister group to Cinnamomum sensu lato. Sequence divergence among the Ocotea species appears to be much lower than among species of the most closely related, likewise species-rich genera Cinnamomum, Lindera and Litsea.